There is something about rocks that begs us to play with them. Have you ever considered
creating a rock garden?
Rock gardens, also known as rockeries or alpine gardens, consist of aesthetically placed rocks with plants growing in the gaps. This particular garden design is well suited to drought-prone areas and alpine regions. Rock gardens tend to require very little care, once they are established. If you look closely, however, you will see that rock gardens are busy places.
A world in miniature
Rock gardens create a microhabitat for a wide variety of beneficial insects and animals. All those nooks and crannies create wonderful hiding places for native ground nesting bees, predaceous ground beetles, lizards, soldier beetle larvae, spiders, frogs and toads. Rocks also provide great sunning spots for a wide variety of amphibians and reptiles. These creatures are in need of all the help we can offer. In exchange for providing them with some real estate, many of these visitors will consume a lion’s share of the pests that damage and carry disease to your garden.
Types of rock gardens
Your rock garden can be designed to look like a dry stream bed, a natural stone outcropping, a Japanese Zen garden, or something else entirely. Stones of different sizes can be used to create pathways or visual appeal. Amphibians are particularly fond of rock gardens with water features. Your rock garden can be very formal or it can simply be a bunch of rocks positioned in ways that you like. There are no rules.
Types of rocks
Most first rock garden designs are built with rocks and stones that are already present on the property. You can also collect rocks and stones from friends and neighbors, or buy specific rocks, stones, and even boulders. Sometimes, you can get free rocks from construction sites, just be sure to ask permission first.
When selecting rocks for your rockery, more porous rocks are better suited than harder rocks. Harder rocks take longer to look natural. Softer rocks look weathered and like they have been there forever much faster. Also, moss grows on it more readily.
You can encourage the growth of moss on your rockery by collecting mosses that you like and putting them in a blender, along with some yogurt or sour milk. Puree this strange concoction into a thick slurry, which is then poured over the rocks. Sooner or later, moss will start to grow.
Once you have selected a site for your rock garden, remove all of the existing vegetation. Many of these plants may become too large for your rockery. Next, loosen the soil enough for the largest rocks to be somewhat sunk into the ground. This will make it look more natural and prevent the whole thing from toppling or rolling around. For the best results, create a shape with the largest stones and fill that area with high quality planting soil. Mud in that soil in to reduce large air pockets before adding medium-sized rocks. Repeat the soil addition and mudding in until all of your stones have been placed. Now you can start adding plants.
Plants used in rock gardens
Rock garden plants need to stay small or your rock garden will disappear. Limited by the lack of deep soil and all those rocks, rockery plants are chosen for their ability to thrive, albeit slowly, in well-drained soil. Plants that can survive in dry environments are called xerophytes.
Some of the more common rock garden plants include:
*Lichens are not actually plants. Lichens are shared living arrangements. Algae or bacteria living within fungal filaments in a symbiotic relationship are what we see as lichen.
Much like stumperies, rockeries use natural materials to create spaces that are both beautiful and beneficial. Once your rock garden is in place, make a point of examining it closely for signs of life. Your rockery will end up creating a tiny world all its own.
Pollinator gardens attract insects that pollinate your crops. They also tend to look lovely.
Similar to butterfly gardens, pollinator gardens use flowers and other plants to attract and provide for pollinators.
What are pollinators?
Pollinators are mostly insects, such as bees and butterflies, that carry pollen from one flower to another, resulting in fertilization and fruit production. Bats, birds, lizards, and even people can be pollinators, as well. Most pollinator gardens use insectary plants to attract these garden helpers.
What are insectary plants?
Insectary plants are those that provide food, shelter, and/or egg-laying sites for beneficial insects at various life stages. Those beneficials may be predators, pest parasites, or pollinators. The flowers that provide this service are usually globe-shaped, such as chives and onions, umbrella-shaped or flat-topped umbellifers, as in seen in carrot and cilantro plants that have been allowed to go to seed. Depending on your region’s pollinator species, the insectary plants suited to your area may be tall or short or both, but most are brightly colored.
As convenient as generic pollinator plants lists are, you will have a more effective pollinator garden if you take the time to identify pollinators native to your area. You can do this by searching online for “pollinators in [my town/state]”, and by contacting your local native plants society, Master Gardeners, and universities. Here, in California, the following native plants attract and provide for pollinators:
*Those marked with an asterisk are recommended by the Xerces Society for Invertebrate Conservation. In addition to adding pollinator plants to your landscape, there are other actions you can take to create a more successful pollinator garden.
While you generally want to keep salt as far away from your garden as possible, there are exceptions. Using a damp salt lick to provide minerals and moisture for bees and butterflies is one of those exceptions. If you have an area that stays damp, simply add salt or wood ashes to the mud. Otherwise, you can put out a dish of slightly salty water. Sea salt contains more important micronutrients than table salt, but table salt is better than nothing. Just remember that salt will damage nearby plants.
Plant for variety
Pollinators are active, in most regions, from early spring through late fall. Ensuring that your landscape includes a variety of insectary plants during that time frame will go a long way toward attracting and supporting valuable pollinators. That variety includes clumps of native plants, suited to your microclimate, and some night-blooming plants that provide for moths and bats.
I use a spreadsheet that lists months across the top and a rainbow of colors down the side to document what is blooming, throughout the year, in my landscape. I add to it as I notice or add new plants. This way, I can see when there are gaps in flower production. Since those flowers provide pollen and nectar, the more I have, the better off my pollinators will be. [The file is too large to share here, but you can email me if you would like a copy.]
Evolution is a relatively slow process. Many of our modern hybrids, especially those with ‘doubled’ flowers, have had their fragrance, nectar and pollen bred right out of them. They may look nice, but that’s all they have to offer.
Quit the chemical habit
Broad-spectrum herbicides, insecticides, fungicides, and pesticides have no place in your pollinator garden. Even those advertised as “safe” can disrupt the breeding, feeding, and existence of beneficial insects. They are probably not very good for us, either. Instead of chemicals, practice least damage Integrated Pest Management (IPM). If you absolutely must use chemicals, apply them at night, when most pollinators are not active.
Dead limbs can be good
Dead branches and dead trees provide nesting sites for native bees. Stumperies also create habitat and food for a variety of birds and other insects. Just make sure your dead tree does not create a safety issue. Trees are extremely heavy.
Your hummingbird feeder provides nectar for far more than just hummingbirds. Chickadees, wrens, and orioles may also enjoy a sweet sip every now and then. And so will many pollinators. The 1:4 sugar to water ratio used in hummingbird feeders is fine for many beneficial insects, too. Just be sure to wash your hummingbird feeder with hot, soapy water once or twice a week to avoid mold and the spread of disease.
Setting aside just a little space in your landscape for a pollinator garden can profoundly increase the number of butterflies, native bees, and other beneficials you see each year. And they could really use our help these days.
You can instill a love of gardening in your child with a children’s garden.
I learned my love of gardening as a child. It all started with a clear plastic cup, a black sponge, and four hard, dry corn seeds. It was an educational toy which had a child insert the sponge into the cup and then push the corn seeds between the cup and the sponge. Each seed was positioned so that it pointed in a different direction. Water was added and the magic of germination began.
I was impressed by the fact that the first roots (radicles) always knew to go down, while the first shoots (plumules) always found a way to move upward, even if it took some twisting and turning. The whole process still amazes me and you can let your child in on some of that magic with a garden designed with them in mind.
Make it child-sized
Adult-sized shovels and trowels can take all the fun out of gardening for a child. So can cheaply made tools that tend to break. Start your children’s garden off right by investing in a well-made child-sized trowel, shovel, hoe, and rake. A small bucket and watering can will be handy, too.
Create a space
You may not want your child(ren) digging around your prized rhubarb or roses, so set aside space just for them and their garden. You can make the space a fun shape, too, such as a triangle, a butterfly, or a series of small circles. This will help create ownership, which will carry your child through some of the more difficult tasks, such as waiting for plants to germinate or flower.
Ask them what they want to grow
Do they want to grow their own pumpkin for Halloween? Or, maybe a sunflower fort, a pizza garden, a Three Sisters garden, a butterfly garden, or a pole bean teepee. The possibilities are practically limitless. Head to the library with your child and explore the gardening books section. Check out several and be sure to grab one or two grown-up gardening books geared towards your region or microclimate while you are at it. That way, as plants are selected, you can research the best way to help them thrive. [See, you don't have to know how to garden to help your child create a garden of their own!]
Grab a pad of paper and a snack and start exploring all the garden design possibilities with your child. Including them in the planning process is important. As you look through photos and drawings together, have your child create a list of plants they want in their garden (if they are old enough). And you will be there to instill some basic gardening principles and to rule out plants not suited to your area. As much as your child may want their own banana tree, it wouldn’t be a good choice for a beginner. In the beginning, you should keep explanations simple. You can always delve deeper into the information for yourself once they go to bed.
Popular children’s garden plants
You can’t go wrong with radishes. They grow so fast that things start happening before your child loses interest. Soaring giants, such as corn and sunflowers, are nearly always a good choice. Plants with large seeds, such as beans, melons, and squashes are easy to work with and the edible harvest is a bonus. Climbing plants, such as pole beans or dramatic red noodle beans, can be used to create hanging walls or secret hideaways. Mounding miniature lettuces and spiky shallots look nice and are always welcome in the kitchen. Cherry tomato plants are prolific and they provide healthy snacks as your child works and plays in the yard. Marigolds, snapdragons, and zinnias add color with little effort.
Include scents and textures
Children are very tactile. They like to touch, taste, and smell whatever is around them. This makes many herbs good choices for a children’s garden. Chives, dill, mint, and sage add delicious aromas and an edible harvest. Fuzzy lambs’ ears and ornamental grasses are fun to touch, while English thyme can make a fragrant ground cover. Edible flowers, such as nasturtiums, pansies, and violets are also good choices. Just be sure to educate your child about how not all flowers are edible.
Plants to avoid
Most edible plants a re a sage bet, but some plants are toxic and should be avoided when designing a young child’s garden. [Especially those marked with an asterisk.] These plants include:
As your child gets older, the risk of toxic plants becomes less of a problem.
Birdfeeders, pinwheels, crawl-throughs, and other special touches can help make your child’s garden even more engaging and fun. Yard sales are a great place to find a child-sized garden bench and unique garden art without spending a lot of money. You may also want to include a fruit cocktail tree. These trees have been grafted to provide more than one type of fruit on the same tree.
If your child is so inclined, encourage them to document their garden. They can create a book of bug drawings, a chart of plant growth, or a photo album of their garden over the seasons.
At the end of the day, after you have both washed up and eaten supper, you may want to curl up with a good gardening bedtime story, such as Frances Hodgson Burnett’s The Secret Garden. It sure worked for me!
How many butterflies did you see in the past year? Not very many, right? You can attract a surprising variety of butterflies to your landscape with a butterfly garden.
Back in my hitchhiking days (the 1970s), I saw millions of butterflies along the Interstate. They would litter the side of the freeway and create colorful clouds in the air. In my own insect-friendly yard, however, I saw no more than a dozen butterflies last year. What happened?
Threats to butterflies
Butterflies have been around for 56 million years, but times are hard. Habitat loss, pollution, pesticide use, invasive species, rising temperatures, and interruptions in their food web all make life difficult for butterflies. Butterflies are particularly hard hit because many of them rely on a single plant species as hosts for their eggs and offspring.
Here, in San Jose, California, we have 144 species of native butterflies. Sadly, we also have the highest density of endangered butterfly species in the nation. Some of the most threatened California butterflies and their host plants include:
Imagine what would happen if everyone added just one butterfly-friendly plant to their landscape.
Most of the plants used in butterfly gardens are insectary plants. Insectary plants are those with the color, shape, and height that appeal to butterflies and other beneficial insects. Common insectary plants include the following:
Members of the sunflower family (Asteraceae) also make good insectary plants. The problem with these generic lists is that many of these plants are non-natives, which can cause problems. Even though these plants provide nectar and pollen for adults, they can actually devastate local butterfly populations because the adults see food for themselves and lay eggs nearby. When those eggs hatch, the larvae have nothing to eat. Put simply, these might or might not be the plants your butterflies need. Or they might be perfect.
I cannot tell you which plants, specifically, to include in your butterfly garden. This is because each region has its own indigenous butterfly population. To find out what is native to your area, conduct an online search for “butterflies native to [your town]. The results may surprise you.
Once you have a list of indigenous butterflies, you can track down their host plants. Host plants are those that will provide the pollen and nectar needed by adult butterflies and the leaves needed for egg-laying and caterpillar feeding. Armed with this information, you are ready to design your butterfly garden.
Planning your butterfly garden
Your butterfly garden doesn’t need to be big or formal to be effective. You can scatter host plants throughout your landscape, if you like. Or you can create an elegant parterre. It’s up to you. Butterflies do use sunlight to warm themselves, so south-facing areas are preferable, as are areas protected from wind. A water feature, such as a bird bath or fountain, can help your butterflies stay hydrated. Rocks, for basking, are always appreciated.
There is also nothing saying you have to install plants specifically for endangered species, although it would be nice. The important thing is to get the correct plants in the ground and helping them to thrive.
Adding a butterfly garden to your landscape does not take a lot of effort on your part, but it can make a huge difference for the butterflies. It will also increase the biodiversity in your garden, making it a healthier environment. Other beneficial insects will also be attracted to these plants. These beneficial insects might be pollinators, predators, or they may parasitize insect pests.
And the flowering plants look lovely.
Did you know that some adult butterflies also eat carrion, rotting fruit, and tree sap, while the larvae of some butterfly species eat ants and other insect pests? I didn’t either.
Now we know.
Rather than rushing to a crowded grocery store at the last minute for holiday meal ingredients, wouldn’t it be nicer to simply walk outside and collect the freshest ingredients possible? You can, with just a little planning.
Creating a holiday dinners garden is a form of planting backwards. You know ahead of time what you will need, so you estimate which ingredients should be planted and when. That way they will become harvestable as they are needed. And your holiday dinners garden is not limited to edibles. Seasonal decorations, such as flowers and greenery, can be found in your yard just as easily.
This planning process may feel overwhelming, at first. Instead of taking on more than is fun, you might want to select one holiday at a time and build on that over time. Either way, it all starts with a calendar.
Create a calendar
Calendars are handy tools, especially for gardeners. You can use printing paper or an inexpensive paper calendar to design your holiday dinners garden. Start by identifying all the holidays you celebrate each year with special meals. In my family, these holidays are New Years’ Day, Easter, 4th of July, Thanksgiving, and Christmas. Mark your family’s holidays clearly on your calendar.
We all have favorite dishes for each of our holiday dinners. In my house, New Years’ Day would never feel right without hoppin’ john and Easter wouldn’t feel like Easter without a ham surrounded by baby beets and carrots.
Whatever your traditional meals include, create generic menus for each holiday dinner. For example:
I do not raise pigs or turkeys in my suburban yard, but including as many of the dishes as I can think of helps me work out the details when figuring out what to plant.
Make a list and check it twice
Using each of the dishes you want to include in your holiday meals, create a shopping list of ingredients that could come from your garden. Be sure to include the date when the ingredients will be needed. Spreadsheets are very handy for this step because this list can get a little unwieldy. You may want to use a separate page for each holiday. Using my menu for the 4th of July, I would start with this:
As you can see, there is some overlap between dishes. [My son, the cook, recently told me that most people have a flavor profile. Apparently, my profile features potatoes, thyme, onions, and garlic!] My avocado tree is not old enough to produce fruit, so I will not include it in my plan just yet.
Nearly all dishes use herbs of one sort or another, so these mostly perennial standbys can be used to create the framework for your holiday dinner garden. The nice thing about perennials is that they are either actively present, or they have been around long enough for you to have canned or frozen some of their harvest.
Common perennial herbs for a holiday dinner might include rosemary, tarragon, and thyme. To make your holiday dinners garden look more attractive and to prevent these frequent members of the mint family from taking over completely, you may want to grow them in containers, placed artfully throughout the garden. Some herbs, such as cilantro, dill, and parsley are not perennials, but they will self-seed once they become established. Others, such as oregano and sage, are perennial in some Hardiness Zones and annuals in others. Once the perennials are in place, you can plan for the annuals.
I love spreadsheets. To me, they make it easy to keep track of a lot of information. You may or may not feel the same way, but they are very handy for this step in the garden design process. You can start with just one holiday or go whole hog with all of them. For this example, I am only using my 4th of July BBQ, but I am including the date for when I add other holiday dinners.
In the first column, list each of your ingredients. In the second column, add the date you want each ingredient to mature. The third column is for a note about whether each ingredient is a perennial, already preserved, or how many days it takes from planting seeds to harvest. Keep in mind that days to maturity found online and on seed packets may be different for your region of microclimate. These numbers are simply averages, but they are still useful.
For each ingredient, count backwards from the holiday the number of days to maturity for a planting date. In the example above, my apples ripen long before July 4th, so I freeze or can them. Then, I see that basil takes 50 to 75 days from planting to harvest, so I count back 75 days from July 4th for a planting date of April 21st. Now, my family loves basil and I plant a lot of it, starting long before April 21st, but I add a reminder in my calendar to plant basil on that date so I know I will have plenty when I need it for that holiday.
If your planting date occurs before it is actually warm enough to plant a specific species, you may need to start it indoors, or buy seedlings at a later date.
In some cases, like celery, I could plant it but I choose not to. For me, celery is fiddly to grow and is so inexpensive at the store that it is not worth the garden real estate. You might feel the same way about onions or garlic. A lot of this will depend on where you live and how much time and space you have. Even if you only select 2 or 3 ingredients for each holiday meal, you’ll be glad you did.
Simply go down the list, counting backwards for each ingredient that needs to be planted. You can add these annual reminders to the calendar in your computer and add alerts in your phone. If you set them to repeat every year, the planning process is done. Before you know it, you will have all the information you need to plant your holiday dinners garden!
Your soil is filled with positively and negatively charged bits of plant food. The percentage of that food being held by soil particles is called its base saturation.
Of course, it’s not that simple. The chemical reactions going on in soil are enough to make a chemist’s head spin. But we are here to simplify and understand, so let’s get started!
Electrified plant food
Plants use electrically charged mineral bits, called ions, as food. The negatively charged bits (anions) are usually found floating around in water. The positively charged bits (cations) attach themselves to soil particles, which are negative charged. Those soil particles have a certain number of electrical charges that can attract minerals. That number is referred to as its cation exchange capacity. The number of those attachments being used is its base saturation.
Playing the percentages
There is some crazy math and lab work involved with calculating base saturation, but we can leave that to the experts. Most soil test results will list separate base saturation percentages for calcium, magnesium, and potassium. Don’t be confused by the fact that these numbers do not add up to 100%. Hydrogen and sodium have been omitted. But what do these percentages tell you?
When the charges of soil nutrients are out of balance, plants cannot absorb what they need to thrive. It doesn’t matter if a nutrient is present if the net electrical charges are wrong. If most of the nutrients in your soil are negatively charged, all of the positively charged bits will be able to connect, leaving many negative bits hanging in isolation. Those leftover minerals impact soil pH.
Base saturation and soil pH
Base saturation measures the number of non-acidic, positively charged bits in a soil sample. That’s why it is called “base” saturation. There are also acidic positively charged bits. Soils with a high base saturation have lots of those acidic, positively charged bits lying around unattached. The more loose acidic bits laying around in the soil, the lower the soil pH.
Using base saturation numbers
Soil test results will tell you how much of each plant nutrient is present and base saturation percentages. One thing you might see is an excessive amount of a nutrient but a normal base saturation percentage. How is this possible? Again, it goes back to electrical charges. Say you have a ton of calcium, a positively charged mineral, but the calcium base saturation is normal. This happens because other charged particles are also present. They can block the excess bits from connecting with anything. Or, there may not be enough negatively charged soil particles available. You need to use both the actual mineral levels and the base saturation percentages when deciding on whether or not to add fertilizer.
This post is an oversimplification of an extremely complex topic, but it is accurate enough to help you get the most out of your soil test results. Soil tests cost around $25 and are worth every penny.
Your soil has a characteristic known as bulk density.
Put simply, if you take a scoop of soil, it will weigh something. If you take a scoop of different soil, it will have a different weight. Those weights are a measure of the material held in that space. No surprise, right?
Also known as scoop density, this measurement tells you how tightly your soil is crammed into a space. It also tells you a lot about your soil’s permeability (ability to drain), infiltration (rate of drainage), porosity (the number of macropores and micropores), soil texture (sand, silt, and clay), and soil structure. This is important information for plant roots.
Another non-surprise: soil is heavy. The weight of the top soil pushes down on the soil below it. That layer pushes down on the layer below that, and so on. This means that soil becomes more and more dense, the deeper you go. This is one reason why so many plants keep their roots near the soil surface.
Bulk density is measured in grams per cubic centimeter (g/cc). Bulk density generally ranges from 1.0 to 1.25 g/cc. Sandy soil tends to have high bulk densities (1.3-1.7 g/cc), while clays and silts normally have moderate densities (1.1-1.6 g/cc). Soils that contain more organic matter tend to have lower bulk density values. Lower bulk densities allow for proper drainage, reducing the chance of fungal disease and helping plants overcome the negative effects of mud and drought.
Too much stuff
If a soil’s bulk density is higher than 1.6 g/cc, your plants are going to have a hard time. Compacted soil restricts the free movement of roots, air, and water. High bulk densities can also prevent germinating seeds from making it to the surface with enough energy to thrive.
What is your soil’s bulk density?
The USDA provides instructions for a DIY bulk density test, but I have to warn you, your kitchen will stink after you bake or microwave a soil sample. A far easier and more pleasant method is to send a sample to a lab. For the price of a bag of fertilizer, your can learn a lot of good stuff about your soil. Soil tests tell you about nutrient levels, the cation exchange capacity, pH, and base saturation numbers, along with bulk density.
Case in point
In 2015, my soil’s bulk density was 1.18 g/cc. By 2019, it had changed to 0.95 g/cc. What happened?
In 2015, my soil test indicated an extreme overabundance of every nutrient, except iron, and compacted clay. [The overfertilizing was done by the previous owner.] To counteract the compaction and the lack of iron (a nutrient needed by plants to help them consume other nutrients), I applied foliar sprays of chelated iron and mulched the heck out of every soil surface with aged compost and chicken bedding.
The iron sprays allowed my plants to make use of and extract the abundant nutrients, bringing them closer to normal, balanced levels. The composted manure and other organic materials created more spaces between soil particles, making it easier for roots, gases, and water to move around. Four years later, all of my plants are growing better and my soil organic matter (SOM) levels went from 3.5% to 7.6%.
If your soil is too dense, your plants can’t thrive. If you know your soil’s bulk density, you can take action to improve it.
Have you ever noticed how the larger bits come to the surface when you shake a container of soil?
This is called the Brazil nut effect. I have no idea why.
Vines - we know what they are, but what makes a vine a vine, and how are they unique?
In some places, the word “vine” is only used to refer to grapevines. But kiwifruit grows on vines. Pumpkins, watermelons, cucumbers, peas, and pole beans also grow on vines. Or do they?
Types of vines
Climbing plants use a variety of methods to reach the sun. They can be climbing or trailing woody-stemmed or herbaceous plants. In general, we call them all vines. Stems tend to be very long and often lack the supportive tissue needed for upright growth. This allows plants to grow upward without the same investment of energy and resources used by trees and other self-supporting plants.
To the purists, grapes grow on vines, all other woody climbers are lianas, and our pole beans, peas, and cucurbits are herbaceous vines.
Now you know.
What does ammonium bicarbonate have to offer your garden?
In the garden, bicarbonates are touted as cure-all treatments of powdery mildew, grey mold, septoria leaf spot, and other fungal diseases, particularly sodium bicarbonate (baking soda) and potassium bicarbonate. The truth is, baking soda is a type of salt and always a bad idea in the garden. Potassium bicarbonate, on the other hand, is an effective organic fungicide.
But what about ammonium bicarbonate? What are bicarbonates, anyway?
In chemistry, the word ‘bicarbonate’ is inaccurate and outdated. It was first coined in 1814 by a chemist who observed that there is twice as much carbon as sodium in sodium bicarbonate. After different types of bicarbonates were identified, with different ratios, the observation became irrelevant, but the habit lives on.
Bicarbonates are the main form of dissolved inorganic carbon in the ocean. In freshwater plants, bicarbonates are released into the water as part of photosynthesis. This can shift the water’s pH to toxic alkaline levels. This continues until nightfall, when photosynthesis stops and respiration releases carbon dioxide, causing pH to return to normal. Bicarbonates commonly act as pH buffers in the human body [plop, plop, fizz, fizz] and in soil.
Bicarbonates are lumped together, incorrectly, as antifungal treatments because they are alkaline. Most fungi prefer a slightly acidic environment. Baking soda and other bicarbonates will raise pH temporarily, but the effect is fleeting and fungi take up where they left off as soon as the baking soda is washed or blown off. Applying enough baking soda to kill powdery mildew would end up adding toxic levels of salt to your soil. Baking soda should be kept out of the garden. Potassium bicarbonate, on the other hand, is an effective organic fungicide.
Salt of Hartshorn
Ammonium bicarbonate used to be the leavening agent of choice, before baking powder hit store shelves. Still used today in flatbreads, German Lebkuchen, Danish Christmas cookies, and Swedish "drömmar" biscuits, ammonium bicarbonate is often referred to in older cookbooks as salt of hartshorn or hornsalt. This form of ammonium bicarbonate used to be made by dry-distilling horns, hooves, leather, and hair.
Ammonium bicarbonate fertilizer
In the plant world, ammonia means nitrogen. This makes ammonia bicarbonate sound like a good idea as a fertilizer, right? In China, ammonium bicarbonate is used as an inexpensive fertilizer. But, because of its instability, it is being phased out in favor of urea. Also, ammonium bicarbonate is an eye, skin, and lung irritant. If you were to use it (against my advice) be sure to wear protective clothing and a respirator.
High soil bicarbonate levels commonly occur when soil or irrigation water have a pH of 7.5 or higher. Alkaline soil and irrigation water tend to have lots of bicarbonate and carbonate ions floating around. These ions tend to attach themselves to and transform calcium and magnesium into less soluble forms that are difficult for plants to use. Also, as these minerals are altered, they leave salt behind in your soil. Not good. When these conditions occur, chelated fertilizers should be avoided. The level of bicarbonates in your soil also determines how much acid is needed to acidify the soil.
If powdery mildew or other fungal diseases are causing problems in your garden, forget the baking soda and ammonium bicarbonate, Instead, space and prune plants for better air flow and apply potassium bicarbonate, Bordeaux mixture, sulfur, fixed copper, or milk. You may also want to apply insecticidal soap (not dish soap) to reduce the spread of disease by ants.
“Give your plants one inch of water each week in summer.”
“Almond orchards use an average of 4 acre feet of water every year.”
But what are water inches and acre feet? Let’s find out!
How much should I water my plants?
Sorry, but there is no single answer. Every situation is different. There are simply too many variables: soil structure, water holding capacity, sun exposure, plant species, age, size, and developmental stage, wind, rain… the list goes on. You can, however, generally keep your plants healthy by providing them with one inch of water each week in summer.
The term water inches is traditionally used in hydraulic mining and it refers to specific tube diameters, vertical surfaces, and pressure levels. We are not discussing those water inches, but there is some math involved.
Since irrigating plants often means the water is being absorbed into the soil as we water, it is practically impossible to know how much water your plants are getting without measuring it at the hose bib end. You can get a general idea of how much water is coming out of your garden hose by turning the spigot on to a set point and timing how long it takes a one-gallon bucket to fill up. If you counted to 15 while your bucket was filling up, you know that your hose puts out 4 gallons a minute, since 4x15 is 60.
Generally speaking, in the world of gardening, the phrase “one inch of water” refers to how much water it takes to cover one square foot of space with one inch of water. Since there are 12” in a foot, you can multiply 12”x12” for your “one square foot” to get 144. This means 144 square inches of water are needed per square foot of garden space. Of course, none of us have measuring cups or watering cans that are marked in square inches, so there is a little more math to do. Don’t worry, though. Once you get used to the numbers, as they apply to your garden space, you won’t have to repeat the calculations.
One gallon equals 231 cubic inches. If you divide your 144 sq. in. by 231, you get 0.6 or a little over half a gallon per square foot.
What about irrigating raised beds?
If you have heavily planted areas or raised beds, you can simply take the length and width measurements and multiply them, using the same steps. For example, say you have a 4’ x 6’ raised bed.
First convert feet to inches:
(4x12) x (6x12) = 48 x 72
Then calculate the area:
48 x 72 = 3456
Since we now know one gallon equals 231 cubic inches, we divide 3456 by 231:
3456 ÷ 231 = 14.9 gallons
This means that your 4’ x 6’ raised bed should be given an average of 15 gallons of water each week in summer.
What about watering container plants?
The math gets a little trickier with containers. Remember the joke about “pie are squared - pie are not squared, pie are round”? Well, this is where you actually get to use that equation. For those of you who need a little geometry refresher:
For example, let’s say that you have a 10” planter pot. Since diameter is twice the length of the radius, we would create this formula:
That may sound like a lot, but it ends up that 78.5 square inches of water equals a little over one-third of a gallon. [78.5 ÷ 231 = 0.34]
If all this math hasn’t made you crazy, let me just tell you that an acre foot equals the amount of water it would take to cover one acre of land with one foot of water. Without going through all the numbers, one U.S. acre foot equals 325,850 gallons of water. In 2018, it was predicted that the average acre of almond orchard would produce 2,150 pounds of almonds. That works out to over 150 gallons of water per pound of almonds.
Watering your plants properly can make or break your garden. Getting a more accurate idea of how much water you are giving your plants can improve their health and reduce water waste. And remember, the “weekly water inch” is just a recommended average for summer. You should always monitor your plants for overall health. If they start wilting and the soil is dry, water them. If they start wilting and the soil is moist, do not add water. Instead, check for root feeding grubs, gopher holes, and hardpan.
Did you know that the amount of water in an Olympic-sized swimming pool weighs over 5.5 million pounds? I didn’t either.
Your chewing gum is made from trees. Well, it used to be.
Tree gums have been used as a chewable treat for over 9,000 years. Mayans and Aztecs used gum from the chicle tree. Ancients Greeks used gum from the mastic tree. Native Americans used gum from spruce trees. It was the Americans, however, who make chewing gum famous to the point that there were not enough trees to produce the gum needed to make gum. It is estimated that over 100,000 tons of chewing gum are consumed each year. Most modern chewing gum is made with natural and/or synthetic rubber and not botanical gums.
But gum isn’t the only goo produced by plants.
Plants ooze several different substances. Gum is only one of them. Plants also produce fats and oils, latex, mucilage, resin, and waxes. The fats and oils produced by plants are more commonly known as essential oils. Essential oils can be responsible for a plant’s unique smell or flavor. Latex is the milky white emulsion of defensive chemicals seen oozing from broken dandelion stems. Mucilage is used to store food and water, thicken membranes, and in seed germination. Succulents and flax seeds have particularly high mucilage contents. Resin is a viscous mixture of antibacterial, antimicrobial acids commonly seen in conifers. Resin dries to a hard, crystalline structure. And then there is plain old sap.
Sap has different components, depending upon where it is found. Xylem sap carries water, hormones, and minerals from the roots to the leaves. Phloem sap conducts sugars, hormones, and minerals from leaves, where carbohydrates are produced through photosynthesis. Sap generally stays fluid. Gums are a specialized type of sap produced by woody plants.
[Plum gum? Sorry, I couldn't resist.]
How do plants use gums?
Gums are produced in a process called gummosis. Gumming refers to the way some plants can break down internal tissues, particularly cellulose, to create a high-sugar sap, or gum, used to seal off wounds and surround invading insects. Gums are commonly found in conifers, such as pine and spruce. Some plants, such as Western poison oak, use gums as protective, gummy seed coatings that delay germination.
How do we use botanical gums?
Botanical gums are water-soluble sugars that are commonly used in the food industry as emulsifiers, thickening agents, and stabilizers. They are also used as adhesives, in printing, candy-making, paper-making, and to make chewing gum.
If you look at ingredient lists on packaged food (and I urge you to do so), you may see some of these botanical gums:
Gums are frequently collected by tapping or otherwise wounding trees with incisions or by peeling back sections of bark. The trees respond to these wounds by gumming.
Tapping is the method used to collect the sap from sugar maple trees to make maple syrup. A tap consists of a metal tube with a downward-pointing lip and a notch or hook from which to hang a bucket. The tube end is hammered into a tree to reach the xylem and a bucket hung from the lip. Sap from the xylem flows (very, very slowly) through the tube, down the lip, and into the bucket. From there, the sap is cooked down to reduce the water content. More modern set-ups use plastic tubing. My students and I once made a delicious syrup/caramel from silver maple trees.
Some of these gums stay soft, while others harden into “tears” which are broken off for processing. If you see gums oozing from your trees, take a closer look.
The soil under your feet and in your garden is [or should be] teeming with life. Worms, roots, microorganisms, and insects call the soil home. The insects are called arthropods and they play a major role in soil health and plant vitality.
In a single square yard of topsoil, there may be 500 to 200,000 individual arthropods.
What are arthropods?
Arthropods get their name because they have paired, jointed (arthros) legs (podos). Arthropods are invertebrates, which means they do not have a backbone. Instead, they have a hard outer covering, known as an exoskeleton or cuticle, made from chitlin. Arthropods range in size from microscopic to a few inches long. As they outgrow their exoskeleton, it is shed by molting.
Soil arthropod species
There are four types of arthropods with many familiar members:
Arthropods are commonly grouped according to their feeding habits. There are fungal-feeders, herbivores, predators, and shredders.
Arthropods that feed on fungi and bacteria include silverfish and springtails, and a few mite species. As they feed, they scrape the fungi and bacteria from the surface of plant roots. As these microbes graze and poop, they make many mineralized nutrients available to plants. Fungal feeding arthropods and the fungi they feed on tend to keep each others' populations in check.
Cicadas, mole crickets, root maggots (anthomyiid flies), rootworms, and symphylans (garden centipedes), feed on plant roots and can become major pests.
Predatory arthropods can be generalists or specialists, eating many types of prey, or only one. Ants, centipedes, ground beetles, pseudoscorpions, rove beetles, scorpions, skunk spiders, spiders, and some mites can be predators, feeding on nematodes, springtails, other mites, and insect larvae.
Shredders tend to be larger and may be seen on the soil surface. They feed on decomposing plant material and the fungi and bacteria growing on those dead plants. As they feed, they shred the plant material, increasing its surface area and speeding its decomposition. This group includes millipedes, roaches, sowbugs, termites, and some mite species. When dead plant material is not available, shredders can become pesky root-eaters.
As arthropods feed and burrow, they provide many benefits to soil health. Moving through the soil, they aerate and gently churn it, improving porosity, water infiltration rates, and bulk density. As they feed, they shred organic matter, speeding decomposition. And when they excrete waste products, they release mineralized plant nutrients and enhance soil aggregation because their waste is coated with mucus. Their feeding also curbs the populations of other soil organisms and opens the way for a wider variety of other, smaller decomposers.
Arthropods often carry around beneficial microbes, in a method known as phoresy, on their exoskeletons and in their gut. These microbes end up helping decompose far more organic matter than they might have, left to their only very tiny devices.
You can help beneficial soil arthropods in your garden by avoiding the use of broad-spectrum pesticides, employing no-dig gardening methods, and installing a wide variety of plant species. Since most soil arthropods live in the top 3” of the soil, the use of stepping stones, stumperies, rain gardens, and water features will all help provide the food, shelter, moisture, and biodiversity needed for healthy arthropod populations.
Let’s us know what you find in the Comments!
Crusting is a type of soil compaction.
When we say soil is compacted, we are referring to all of it. When compaction occurs below the soil surface, it is called hardpan. When the problem is at the surface, we call it crusting.
Healthy soil is lumpy. These lumps are called soil aggregates. Soil aggregates are made up of different sized minerals, bits of organic matter, and spaces, called macropores and micropores. Those spaces are critical to soil and plant health, as they provide pathways for air, water, and roots.
When surface aggregates are broken into smaller and smaller bits, the soil particles shift around, dry out, and realign into a smooth, plate-like structure, called a crust. As that crust dries out even further, cracks commonly appear. These cracks are nearly always at 120° or 90° angles.
Types of crusting
Soil crusting can be classified as chemical, biological, or physical. Chemical crusts are the result of salt or other mineral deposits on the surface that commonly occur in arid regions. Biological crusts are generally caused by algal deposits left behind from slow-draining ponds and they tend to be lumpier than other soil crusts.
Physical crusts may be structural or depositional. Depositional crusts are the result of fine soil particles carried in runoff being deposited over an area. Structural physical crusts are more likely to occur in the home garden. Crusting is particularly common in clay soils because the particles are already so tiny. Flat clay particles average less than 2 μm and are attracted to one another by electrostatic forces. Silt is boxier and 2 to 50 μm, while sand particles are larger than 50 μm. Neither silt or sand particles are attracted to one another electrically. If your clay soil contains high levels of magnesium and/or sodium, the odds of soil crusting are even higher. [What does your soil test say?]
What causes structural crusting?
Rototilling and rain are the two most common causes of crusting. Frequent digging or rototilling disrupts microorganism populations and breaks up soil aggregates. Those aggregates are needed to allow air and water to move through the soil. Soil microorganisms are partly responsible for maintaining those soil aggregates and for feeding many of your plants.
As heavy rain (or sprinkler water) falls, each drop hits the topsoil and breaks up soil aggregates into smaller and smaller particles. These smaller particles are more prone to compaction and surface crusting.
Problems with crusting
Compacted soil makes it difficult for water, air, and roots to move through. It also slows soil gas exchanges and drainage. Crusty soil slows water infiltration and makes life very difficult for germinating seeds and young seedlings. In fact, crusting can stop germinating seeds from getting to sunlight altogether. Crusting also increases the chances of runoff and urban drool. If the soil below has reached its watering holding capacity, crusting can prevent evaporation, causing roots, worms, insects, and microbes to drown.
Soil crusts are rather fragile. As they are damaged, they tend to break apart, allowing the soil to erode very quickly. [My Burner readers know what I mean. Pre-event, the Black Rock Desert crust is firm and dust levels are relatively low. As traffic picks up, the surface crust is damaged and dust storms can become rather impressive. For you non-Burners, just think of the Dust Bowl of the 1930s.]
Correcting crusty soil
Patches of crusting can be corrected by lightly breaking up the soil surface and planting cover crops, green manure crops, or cereal grains. You can also top dress the area with aged compost or manure, or reduce damage by mulching.
How to prevent crusting
Rather than rototilling or digging, use mulch to encourage worms and soil microorganisms to do the work for you. Also, after harvesting an area, cover it with straw, mulch, or a fast-growing cover crop to absorb rain droplets and prevent erosion and compaction.
Why do some fruits continue ripening after being harvested, while others do not? It all depends on whether or not they are climacteric.
Ripening is a highly complex developmental process. It is largely dictated by plant genetics and partially affected by climate. As fruits ripen, distasteful flavors are broken down, sugar levels and other pleasant flavors increase, pectins soften, acid and carbohydrate levels change, colors change, and a lovely aroma is released. One of the most important players in the ripening process is ethylene gas.
Ethylene gas is a plant hormone produced by nearly all fruits. It is used in response to injury and to ripen some fruits. Climacteric fruits have very sensitive ethylene gas receptors. It doesn’t matter whose ethylene gas it is. Once these receptors are triggered, a domino effect of ripening is activated: respiration and ethylene gas production spike, whether or not they are still attached to the parent plant. Increased respiration and ethylene gas drive the ripening process in climacteric fruits.
Ethylene gas is the reason why bananas or apples stored near other climacteric fruits will cause them to ripen faster. It is also why bananas are now sold with plastic or wax over the stem ends - to reduce ethylene gas emissions.
Non-climacteric fruits also produce ethylene gas, but at much smaller rates. These fruits rely on other methods of ripening. This is a new area of study and very little is known at this time except that auxins and abscisic acid are believed to play critical roles.
Which fruits are climacteric?
Apples, apricots, avocados, bananas, blueberries, cantaloupes, figs, kiwifruit, mangos, nectarines, papayas, peaches, pears, pineapple guava, plums, tomatoes, and some hot peppers are climacteric. This means they can be removed from their parent plant and will continue to ripen.
Bramble fruits, such as blackberries and raspberries, cherries, citrus, cucumbers, eggplants, grapes, melons, peppers, pineapples, pomegranates, pumpkins, squashes, strawberries, and watermelons are not climacteric and must be left where they are until they have ripened fully. If these fruits are harvested before they are ripe, put them in the compost pile or feed them to your chickens because they will never ripen. There are some non-climacteric apricots and melons, while some varieties of grapes and strawberries, while not climacteric, do have active ethylene gas receptors.
Whether a fruit is climacteric or not, leaving it on the parent plant for as long as possible is the only way to get the best flavor and nutritional value.
After the climacteric stage has been reached, plant respiration returns to normal or below normal and fruits become far more susceptible to fungal infections. In other words, after climacteric (and non- climacteric) fruits have reached their peak of flavor and sweetness, they start to rot.
Now you know.
Cedar chests repel moths. Adding pencil shavings to potted plants repels or kills insect pests, such as ants, carpet beetles, cockroaches, fleas, mosquitos, moths, spiders, and termites. At least, that’s what they say.
Can we really use cedar as an insect repellent? It sounds (and smells) so nice…
Let’s start by learning a little more about what we mean when we use the word cedar.
Cedar is a conifer. The word ‘cedar’ refers to any of five Cedrus trees, all of which produce oils said to repel moths whose larvae eat fabrics, such as wool. These are ‘true cedars’, none of which are native to North America. Other trees lumped together with Cedrus are the Thuja, or cypress trees, three of which are native, and a few juniper trees. Cedar, cypress, and some junipers do contain chemicals, known as terpenoids, which are used to protect themselves against insect pests. The terpenoids used by cedar and cypress are not the same, however. Cedars use terpenoids called sesquiterpene hydrocarbons, while cypress and juniper use something called thujone. Thujone is also found in common sage, some mint species, mugwort, oregano, tansy, and wormwood. In both cases, some insects are repelled while others are not.
Insects and cedarwood oil
Your grandmother was right about her cedarwood hope chest - it really does repel clothes-eating moths. It does nothing, however, against fleas, mosquitos, spiders, and most ants. In its defense, if you have ordorous or Argentine ants, cedarwood oil will help keep them away. It will also repel or kill carpet beetles, cockroaches, and termites, none of which are a threat to your plants.
Dangers of cedarwood
Before you jump on the cedarwood oil bandwagon, however, you need to know that there is a downside. Research has shown that, while exposure to cedar wood oils can interrupt the reproductive and developmental cycles of peanut trash bugs, Indian meal moths, and forage mites, prolonged exposure to these oils increases your chances of getting cancer.
Strangely enough, European turnip moth larvae love eating cedar. Isn’t life weird?
Soil organic matter (SOM) is a category found in soil test results and it is critical for good soil health.
Soil organic matter levels can range from practically nothing to as much as 90%. Deserts are at the low end of the scale, while low lying, wet areas (think peat bogs) are at the high end. Most topsoils range from 1% to 6% soil organic matter. Soils containing 12% to 18% organic matter are called histosols. Histosols tend to be acidic, low in nutrients, and have poor drainage.
Components of soil organic matter
Soil is made up of minerals (45-49%), water (25%), air (25%), and things that were or are alive. These lifeforms can be insects, plants or animals, in various stages of living or decomposing, microbes, and any substances created by those living things. These lifeforms, both alive and dead, and their secretions and exudates, are what make up soil organic matter.
Soil organic matter is approximately 5% living things, 10% fresh residue, 33-55% stabilized organic matter, and 33-50% decomposing organic material.
Organic matter and soil health
Maintaining healthy soil is a big part of the Integrated Pest Management (IPM) practices that allow us to grow plants with a minimum of chemical interventions. Healthy levels of soil organic matter provide biological, physical, and chemical benefits to your soil. Sufficient soil organic matter improves soil structure and water retention and infiltration. It also increases soil aggregation, or clumping, which increases the number of macropores and micropores through which water, air and roots can move. Organic matter improves soil biodiversity, and the absorption and retention of pollutants, while reducing soil compaction, crusting, and urban drool. Organic matter also creates a buffer against changes in soil pH.
Organic matter and plant health
As plants, animals, and insects decompose, a variety of compounds become available to plants, increasing soil fertility and nutrient cycling and storage. These compounds include carbohydrates (sugars and starches), fats, lignin, proteins, and charcoal. As these compounds are broken down further, or mineralized, they increase your soil’s cation exchange capacity. This means plants are better able to absorb atoms and molecules of plant food through root hairs. Insufficient soil organic matter can cause mottling and other signs of nutrient deficiency.
Soil organic matter also acts as a carbon sink, reducing the amount of carbon in our atmosphere. As a major player in the carbon cycle, soil organic matter is believed to hold 58% of the Earth’s carbon. We can help keep it there (and out of our air) with no-dig gardening and cover crops.
How to increase soil organic matter
Before increasing anything in your soil, send a sample to a lab for testing. There is no other way of knowing what, exactly, is present without a soil test. It would be rare for most soils to have a problem with increasing organic matter levels, but it’s better to be safe than sorry. Plus, then you’ll have all that other great information!
You can increase organic matter levels in your soil with these tips:
Remember, soil organics matter!
Very often, you can propagate new plants from old ones by taking a piece of the parent plant and giving it a warm, moist place to grow. This works because plants have undifferentiated cells that can become any part of the plant. Given the right conditions, meristem tissue that was going to become stem or leaf can develop into roots instead. Vegetative propagation can take several forms.
Many houseplants are propagated by cutting off a stem and sticking it in water until roots appear. Succulents are particularly well suited to propagation by cuttings. Simply break off a leaf and stick it into some soil. Cuttings can be taken from leaves, stems, and roots and coaxed into producing new plants with varying degrees of success. Some plants root faster and more easily than others. Generally speaking, woody stems are more difficult to propagate with cuttings than soft-stemmed plants.
Many bulbs and perennial plants benefit from being divided every few years. This happens because the root system can become overcrowded. Artichokes, chrysanthemum, germander, saffron crocus, and yarrow often benefit from being divided. If you dig up one of these plants, you can pull or cut them into smaller portions and replant elsewhere. Division is normally done in autumn, unless it is an autumn-blooming plant, such as saffron crocus, in which case division is performed in spring. Autumn temperatures give plants time to recover and develop new root systems.
Strawberry runners are an example of layering. Layering is a method in which portions of a plant are bent to the ground and covered with soil while still attached to the parent plant. The parent plant provides water and nutrients needed by the daughter plant until roots emerge from the soil-covered nodes. Once the clone is established, it can be separated from the parent plant. In many cases of layering, the section of the plant touching the soil is purposely wounded to stimulate rooting. There are six types of layering: air, simple, compound, tip, and trench methods.
Scions are young twigs cut from parent plants, usually trees, which are then grafted onto other trees. The meristem tissue found within the scion dictates what sort of blossoms and fruit will be produced. Scions are what make “fruit cocktail” trees possible. These are trees that produce a variety of fruits. You can have a single citrus tree that produces Valencia and Navel oranges, kumquats, grapefruits, and tangerines, or you can have a stone fruit tree that produces peaches, nectarines, apricots, and almonds.
Suckers and root sprouts
Suckers are shoots that occur at the base of a tree or shrub. Root sprouts come up from the root system, usually at a distance from the parent plant. Suckers, also known as basal shoots, and root sprouts can be removed from mature plants and encouraged to take root elsewhere. To do this, you will need to carefully remove them from the parent plant and place them in moist soil.
What about GMOs?
Propagation generally refers to breeding or reproducing plants by natural processes from parent stock. How you define natural processes may alter how you feel about genetic modification. Before digging in your heels, you need to know that plants, bacteria, and fungi have been modifying genetic material [their own and that of other living things] long before we got started in the lab. For better or worse, genetic modification has a role in modern plant propagation. For one thing, without genetic modification, there would be no seedless watermelons. Seedless watermelons happen because plant breeders do two things:
The resulting offspring have 33 chromosome and are highly unlikely to have viable seeds. That’s why you still get an occasional seed in your seedless watermelon.
Rather than going to the store to buy new plants, you can often propagate your own for free using these methods.
Your tree may house a tiny, fungi-farming beetle called the polyphagous shot hole borer, but I hope not.
Native to southeast Asia, these invasive beetles are threatening trees in Israel and California with Fusarium dieback. Fusarium dieback is a fungal disease that blocks the flow of water and nutrients through a tree’s vascular system. And polyphagous shot hole beetles actively farm those particular fungi. We will get to that in a minute.
Polyphagous shot hole borer identification
Polyphagous shot hole borers (Euwallacea fornicatus) are smaller than a sesame seed. You could fit 6-10 females, end-to-end, across a dime. Females are black and males are brown and wingless, but you will probably never see a male. Sightings are rare and no wonder. Males stay in the galleries and you could fit 12-18 of them across the face of a dime.
Polyphagous shot hole borers look identical to another invasive borer called the Kuroshio shot hole borer, or tea shot hole borer (Euwallacea fornicatus). The tea shot hole borer prefers tea plants in Sri Lanka, while the polyphagous shot hole borer appears to have a voracious appetite for over 110 tree species. [The word polyphagous means eats many things.]
Host trees and signs of infestation
Traditionally, polyphagous shot hole borers tended to only infest dead or dying trees. Having been accidentally introduced to new regions, these pests have developed a taste for healthy trees. Once trees are infected, they can die. Host trees include:
External symptoms of infestation often look innocuous. Slightly weepy, small damaged areas of the bark, the presence of white frass, maybe a little sawdust or sugar volcano action is all you can see from the outside. If you look very closely, you may see several exit holes, about the size of the tip of a ballpoint pen. The inside of an affected tree is something else entirely.
Polyphagous shot hole borers chew holes that penetrate 1/2” to 1-1/2” into the wood. Then they start burrowing, creating galleries. Black flecks and tunnels can be seen throughout an infested tree. These black areas indicate where Fusarium fungi are being farmed.
Polyphagous shot hole borer as farmers
Polyphagous shot hole borers are a type of ambrosia beetle. Rather than feeding on bark or wood or sap, ambrosia beetles eat fungi that they grow for themselves. Polyphagous shot hole borers have tiny pockets on their exoskeleton. In these pockets, they carry spores of the Fusarium euwallaceae fungi. After burrowing into a tree, the borer starts growing these fungi along the walls of the burrowed galleries. The fungi provide adult and larval forms of polyphagous shot hole borers with food in a protected environment and the borers carry the fungi to new trees. It's a win-win situation for them. The problem is, this fungi causes Fusarium dieback. Fusarium dieback causes branch dieback, canopy loss, and it can kill trees.
Polyphagous shot hole borer management
Yellow sticky cards, purple prism traps, and multiple funnel traps have been used with some success. Because polyphagous shot hole borers have no natural enemies here in California, and because they live inside the tree, safe from insecticides, prevention is worth the effort.
Polyphagous shot hole borers are most commonly spread on firewood. If infested trees are chipped into mulch, the borers can catch a ride to your trees, so always inspect wood chips before accepting them. Wood chips cut into pieces smaller than 1” are generally considered safe because the borers get chopped up too. Personally, if I saw black galleries, I would refuse delivery just in case.
If you suspect polyphagous shot hole borers have found your trees, please contact your local County Extension Office right away.
Conks are woody, shelf-like structures produced by some fungi. These fruiting bodies are often seen on trees and they can indicate fungal diseases, such as canker rot.
Conks are the reproductive form of a large group of fungi known as polypores. Polypores are mostly found in the bark, trunks, and branches of trees, though some are found in the soil. Polypores play major roles in the decomposition of wood, so their presence often indicates decay. Polypores are also important in nutrient cycling, so they aren’t all bad. This is a large, diverse group but they all have conks in common.
The conk clan
This group is defined, not by genetics, but by growth behavior, so it is very diverse. The most common types of conks include:
Also known as bracket fungi, or shelf fungi, this group (Basidiomycota) produces circular, shelf-shaped fruiting bodies that can appear in rows, columns, or singly. Basidiomycetes are the only fungi known to break down lignin. Lignin is what makes trees rigid and hard. The disease that accomplishes this feat is known as white rot.
Some conks are annuals while others are perennials, some of which can live for 80 years or more. In either case, they tend to be tough, leathery, sturdy growths. These growths produce spores, called basidiospore, in pores found on the underside of the conk.
Conks appear to grow directly out of the wood on which the fungi feed. If you were to cut one open and look at it closely, you would see two layers: a tube layer and a supporting layer. The tubes are honeycomb-like structures lined with a spore-forming surface, called the hymenium, and the supporting structure creates the shelf and its attachment to the tree.
The problem with conks is that their presence indicates that some sort of fungi has taken up residence in your tree. If your tree has conks, the first step is to identify the type. Some fungi are worse than others.
Preventing fungal conks
The fungi that produce conks generally enter trees through mechanical wounds, damaged roots, broken or rubbing branches, frost cracks, sunburn damaged bark, and improper pruning. Fungal spores travel on the wind, rain, and on birds and insects, so keeping your tree’s protective outer layer intact is the best prevention. This means you should:
If you have a tree with conks, you should probably contact a certified arborist. They can inspect the tree for structural integrity and to determine the extent of the infection.
Conks may look cool, but you don’t want them on your trees.
Can you see a crack in the trunk or branches of your tree? It may be canker rot.
Canker rot is a collection of fungal diseases that eat away at the interior of tree trunks and branches, weakening the tree and setting the stage for other pests and diseases. Canker rots can also girdle your tree and kill it. While most commonly seen in ornamental trees, canker rot can occur in apple and other fruit and nut trees. Trees with canker rot can be extremely dangerous and should be dealt with right away.
Canker rot identification
Cankers are open wounds, or lesions. Cankers can be a few inches long and wide, or several feet long, depending on the fungal species. The bark next to these cankers dies, becoming discolored, often lighter or orangish, and it is tightly bonded to the canker. After a year or so, the dead inner bark turns black and stringy. This looks a lot like sooty bark canker, but canker rot can also have lenticular (lens-shaped) lighter areas in the bark. Unlike other canker diseases, canker rot affects both bark and inner tissue.
Canker rots can also cause swelling, sunken areas, gnarled bark, and conks. Conks are shelf-shaped fungal fruiting bodies. After spores are released, the conk will dry out and darken. It may remain on the tree or fall off.
If you were to see inside your tree, you would see that the heartwood and sapwood have become discolored. Instead of the warm, rich yellowish-browns of healthy wood, you would see gray, orange, or even pink-tinged wood, often extending 3 or more feet beyond the canker.
Canker rot lifecycle
The fungi responsible for canker rot usually enter trees through pruning cuts and wounds. Fungi attach to the wood and then move to the cambium to access the water and nutrients flowing through the vascular bundle. This is what causes the canker. The fungi also move to the bark, where they eject spores, which are then carried on wind to nearby trees.
How to control canker rot
As always, healthy trees are better able to protect themselves. This means selecting species suitable to your microclimate, planting them at the proper depth, irrigating and fertilizing your trees properly, and monitoring for signs of problems. Other actions you can take to reduce the chance to canker rot occurring in your trees include:
Canker rot can make your tree dangerous. If it is a large tree and the canker is directly facing or opposite the prevailing wind, your tree can be blown over. Large trees weigh several tons and can be extremely dangerous. If you suspect canker rot, call a licensed arborist right away.
You can grow a surprising amount of food in your own yard. Ask me how!