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.
Root sprouts appear to be random baby trees or shrubs that keep popping up in your landscape. Getting rid of them can be difficult.
Many plants pass on their genetic information through seeds. Seeds are spread by birds, the wind, people, and herbivores. Plants can also propagate themselves vegetatively using suckers, adventitious shoots and root sprouts. These growths emerge from adventitious buds, which occur close to the vascular bundle, where they will have easy access to water and nutrients. The different names refer to where they occur. Suckers, also known as basal shoots, occur at the base of a tree or shrub. Adventitious shoots can form on stem internodes, leaves, roots, or callus. Root sprouts emerge from the root system.
Root sprout growth
Root sprouts often grow out of adventitious buds found on a tree’s extensive root system. Root sprouts are clones of the parent plant.They can be found a significant distance from the parent tree. Root sprouts can also grow from the roots of a tree that has fallen or been cut down. Apple, cherry, and guava are especially prone to root sprouts.
If a plant produces root sprouts, it is said to be surculose.
Root sprouts can be used to propagate new plants. They also use up a plant’s energy stores and can make a mess of your lawn or landscape. They are also responsible for one of the world’s biggest and oldest life forms.
The world’s largest life form
Tree roots spread. Then they can send up new root sprouts, which then create more roots and more root shoots. Given enough time and space, this process can create something really HUGE! In fact, root shoots are responsible for one of the world’s largest and probably oldest life forms: the singular root system of a grove of male quaking aspen found in Utah. Known as Pando, this root system covers 106 acres, weighs approximately 13 million tons, and is believed to be 80,000 years old. Sadly, Pando, is dying. Pando’s decline is believed to be a combined result of drought, grazing, and fire suppression. The U.S. Forest Service and private groups are trying to save it, but repeatedly killing off the root shoots with grazing (or hand pruners) does take its toll.
Why do trees produce root sprouts?
Some trees are more likely than others to produce root sprouts. In some cases, it is simply the tree’s normal method of propagation. Root sprouts can also be a sign that a tree or shrub is stressed. That stress can take many forms:
What can you do about root sprouts?
First, keep your tree as healthy as possible. Water it, feed it, protect it from lawn competition, weedwackers, and car doors. Mulch around but not touching the tree. Do a little research to find out what type of tree you are dealing with and what its needs are, and provide for those needs. This will reduce the tree’s drive to reproduce in this way.
If you spray herbicides on a root sprout, you will be poisoning the parent plant as well. Instead, you can kill the individual buds by tearing the new growth off, as close to the root as possible. Of course, this may require some soil removal. If you can tear the root sprout off of the root, you are likely to damage or kill that particular bud. If there is a section of root that continually puts out unwanted root sprouts, you can dig up the offending root and severe it from the tree or shrub. If all of that sounds like more work than it is worth, simply snip them off at soil level each time you see them.
There are also products available that you can spray on root sprouts, but I do not use them. Reviews appear to be highly mixed and applying just a little bit too much can seriously damage the tree or shrub those root sprouts came from. Other people swear by them. It's your call.
If you are really sick of all the root sprouts in your lawn, contact a licensed arborist. They can safely apply a growth inhibitor.
Prune limb borers can damage stone fruit trees, such as almond, apricot, cherry, nectarine, and peach, as well as oak. Gumming and reddish orange frass are common signs of prune limb borer infestation.
Prune limb borers (Bondia comonana) are not as common as American plum borers, but it is a good idea to know what to look for, just in case.
Prune limb borer description
Prune limb borer moths are not very large. They have a 3/4” wingspan. The forewings are grey with black and brown markings. Like many grubs, prune limb borer larvae are dull white or pinkish with a large, dark head. They are usually 1” long.
Prune limb borer lifecycle
Prune limb borer larvae overwinter inside your trees in cocoons. In spring, adult moths emerge and mate. Female prune limb borers lay their eggs on callus tissue, where narrow crotches between branches create wrinkled bark, near graft unions, and on crown galls. Eggs are also laid in wounds from pruning, tree supports, or poorly aimed weedwackers. There can be as many as four generations each year.
Prune limb borer damage
It is prune limb borer larvae that do all the damage. As soon as eggs hatch, larvae begin burrowing into the host tree. Erratic tunnels between the bark and cambium layer interrupt the flow of water and nutrients and weaken the tree structurally. Heavy infestations can weaken scaffold branches, making them likely to break off in strong winds and when supporting heavy crop loads.
Prune limb borer management
Mature, healthy trees can often withstand a prune limb borer or two, but young trees can be killed by heavy infestations. Like other borers, these pests are easier to prevent than control. Inside the tree, they are safe from predators and pesticides. Use these tips to prevent prune limb borers from taking up residence in your trees:
Over-the-counter pesticides and insecticides are not effective against prune borers. If you have a badly infested tree, it may be worthwhile to hire a professional to apply a residual, contact insecticide.
We all know what tree branches are, but what are scaffold branches and why are they important?
What are scaffold branches?
Trees have an underground root system, a trunk, primary branches, secondary branches, and so on. Both above and below ground, the fractal splitting of growth creates ever-smaller and more delicate parts. Twigs emerge from lateral branches and lateral branches grow out of primary scaffold branches. Scaffold branches are the heaviest limbs which create the structure of a tree’s canopy, or silhouette.
Scaffold branches and pruning
Pruning and tree training are the best way to ensure your trees are healthy, safe, and productive. Before putting your tree saw to work, you need to know about scaffold branches.
Mature scaffold branches are rarely pruned or removed, unless they are severely damaged or diseased, as they provide the overall structure of a tree’s shape. Young trees, however, must be trained into forms that allow for proper sun exposure and air flow while maintaining branches that are less likely to break once burdened with lateral branches, twigs, leaves, and heavy fruit crops.
The angle at which branches attach to one another, known as the angle of attachment or the branch axil, determines the strength of that connection. Angles of attachment that are too narrow become areas of weakness later on. These V-shaped crotches also provide overwintering sites for American plum borers, prune limb borers, and many other pests. Branch axils of 30° or more generally result in sturdy attachments that can withstand strong winds and heavy fruit or nut crops. Downward hanging branches are highly prone to breakage. The best branch axils are 45° to 60° angles.
Selecting scaffold branches
When training young trees, you want scaffold branches that are appropriate to the species, spaced properly, and at good angles. You should avoid having more than two scaffold branches at the same distance from the ground. Scaffold branches should be at least 8” to 16” apart, vertically. Also, select scaffold branches that are positioned radially around the trunk so that they are not growing directly above or below each other.
As you train your tree, remember to avoid cutting the branch collar and do not use sealants. Sealants often trap moisture against the wound and create the perfect environment for rot. Your tree knows how to heal itself and will form callus tissue over and around the wound.
Take a look at the scaffold branches on your trees. Are they strong and healthy or do you need to do some re-training this dormant season?
Vein clearing is nearly always a sign of viral disease. It can also indicate herbicide poisoning, bacterial disease, or fungal disease.
Normal, healthy leaf veins are green or white, and opaque. In the case of disease or overspray, those veins may become lighter than normal to the point of becoming translucent, clear, or pale yellow. This is a form of chlorosis.
Viral diseases and vein clearing
Viral diseases, such as cucumber vein yellowing, papaya ringspot, and turnip vein clearing, often appear initially as lighter colored veins. Many mosaic viruses, such as cucumber green mottle, pea seed-borne mosaic, and squash mosaic start with similar symptoms.
Other diseases and vein clearing
Fungal diseases, such as Fusarium wilt, occasionally cause vein clearing. Bacterial wilts, such as Verticillium wilt, may also exhibit vein clearing during the initial stages of infection. In bacterial wilts, the xylem walls either dissolve or rupture, releasing fluids into nearby cells and leaving the veins looking translucent.
Vein clearing and overspray
Vein clearing can also be seen when overspray occurs. Overspray describes the way herbicides and other chemicals can drift on a breeze to unintended plants. After landing on a plant, the herbicide is absorbed and transported throughout the plant in the xylem. Older leaves generally exhibit damage to margins (edges) and interveinal (between vein) areas. Younger leaves respond differently, showing chlorosis of the veins, especially the midrib.
Vein clearing can also be a phytotoxic symptom. Phytotoxic means “poisonous to plants”. In some cases, we apply insecticides, oils, or other treatments with the best of intentions. Whether due to extreme sunlight or temperatures or something else entirely, these treatments can go awry, causing symptoms such as vein clearing, along with wilting, leaf loss, or flower drop. In other cases, these symptoms may appear for no obvious reason at all!
Cherry vein clearing, for example, is believed to be a genetic mutation that is spread by grafting affected scions onto unaffected wood. Some researchers believe this mutation is caused by a boron deficiency in the soil, but no one is sure just yet.
In some cases, vein clearing is a short-lived symptom. As the disease or toxicity progresses, vein clearing may resolve itself and show up as completely different symptoms, depending on the initial cause. These symptoms may include dwarfing, puckered leaves, variegated yellow and green on leaves, and vein banding. Vein banding is similar to vein clearing except that bands of translucent and opaque green, yellow, or white are seen.
If you see vein clearing, take a closer look, note any other symptoms and send me pictures!
You can grow a surprising amount of food in your own yard. Ask me how!