Fir bark mulch is made from the chopped or shredded bark of conifers, such as redwood, pine, and fir.


Fir bark mulch is just one of several different types of mulch you can use to reduce erosion, crusting, and soil compaction. Mulch also helps retain moisture, reduce weeds, and it stabilizes soil temperature. As it breaks down, it even adds nutrients to the soil. Mulch can be straw, grass clippings, compost, wood chips, or fir bark. Fir bark and wood chips last a lot longer than the other mulches. 


Which is better for your landscape: wood chips or fir bark?

Fir bark v. wood chips


Wood chips come from the interior of a tree. They can be hardwood, softwood, or a combination of the two. Generally speaking, large wood chip mulches will need to be replaced every 5 to 7 years, while smaller chip mulches need to be replaced every 2 to 3 years. Fir bark, because it is made from plant material that has evolved to provide protection against the elements, lasts 7 to 10 years. Besides durability, there are other factors to consider:

• Cost - you can usually get wood chips for free from tree trimmers, while fir bark is usually purchased in bagged form
• Stability - fir bark is lighter and more likely to blow or wash away than wood chips
• Ease of installation - wood chips can be shoveled easily, but they are heavy; fir bark is much lighter, but it has sharp fibers that can result in many splinters
• Slope - finely shredded fir bark is more likely to stay in place on a slope; wood chips tend to slide downhill
• Appearance - many people prefer the look of fir bark over wood chips; chips are chunkier, which looks more rustic, while bark is shredded, so it has a softer appearance

Grades of fir bark mulch

Fir bark mulch comes in a variety of sizes, or grades: 

• finely shredded, often called gorilla hair
• mini bark - 1/4” to 1/2” pieces
• small bark - 1/2” to 1-1/2” pieces
• medium bark - 1” to 2” pieces

The larger the pieces are, the bigger the spaces between them will be. These spaces allow air and water to flow through. Tiny pieces of mulch will hold more water in the soil, but allow for less gas exchange. Yes, it is a balancing act. The biggest thing to consider with fir bark mulch is the likelihood of flowing water in the area. Fir bark has a waxy coating that prevents it from absorbing water, plus it is very light, so it will simply float away. Wood chips, on the other hand, will absorb the water and are more likely to stay where they are.


Calculating coverage

To determine the cost of using fir bark, you will first need to calculate the area to be covered, and then deicide the depth of coverage needed. Generally speaking, mulch should be 2” to 4” thick. Newly developed areas should be given 3” to 4” of mulch, while established areas can often do with less. One cubic yard (27 cubic feet) of medium sized fir bark will cover an area of 324 square feet to a depth of 1 inch. Let me say it again:

As an example, let's say you have two areas that are 40 feet long and 3 feet wide, and one area that is 30 feet long and 2 feet wide. Here are the initial calculations:

    = [2 (areas) x 40 (feet long) x 3 (feet wide)] + [1 (area) x 30 (feet long) x 2 (feet wide)]
    = [2 x 40 x 3] + [30 x 2]
    = [80 x 3] + [30 x 2]
    = 240 + 60
    = 300 square feet


In our example, one cubic yard of medium fir bark would give us a little more than one inch covered, since we only need 300 square feet and cubic yard provides 324 square feet. If we decide to use a 2 inch layer, we would need a little less than two cubic yards of fir bark. If you are a number nerd, like me, you could calculate the exact amount needed for a 2 inch depth (1.85 cubic yards), but that really isn’t necessary because a little extra is fine, or you can use it to top off your container plants.


Cost of fir bark mulch

Currently, in the Bay Area, prices for fir bark mulch average $67 per cubic yard, plus an average delivery fee of $77. A few suppliers will offer free delivery if you buy more than 7 cubic yards, but that is more than most of us will ever use. Some suppliers will also let you pick up fir bark in bags or trucks, so you can save money that way. Of course, it also means you will be picking up all that mulch One More Time. (After moving a full dump truck load of wood chips from my driveway to the back yard using a wheelbarrow, back and forth over 100 times, I can tell you that it feels like an ordeal after a while!)


Nitrogen loss (and gain)

If you use freshly chipped wood mulch of either type, keep in mind that it will, for the first 6 to 8 weeks, pull nitrogen from the soil as is begins to break down. You may need to add a little extra nitrogen during this time. In the long term, as the wood continues to break down, it will add nitrogen to the soil.


Fir bark provides an attractive, durable, and protective covering for your soil.

Every drop of rain that falls on your landscape ends up somewhere. Where that water falls and where it ends up is called a watershed.


Rainwater may be absorbed by plants, sipped by local wildlife, or it may evaporate back into the atmosphere. Rainwater can also wash away valuable topsoil, carrying fertilizers and pollutants into our groundwater supplies, rivers, lakes, and oceans. In fact, the California Native Plant Society tells us that urban drool is the #1 source of ocean pollution. To prevent water waste, pollution, and runoff, a new approach to landscape design was created to protect our precious watersheds.


Watershed approach to landscape design

The watershed approach to landscaping uses garden design, installation, and maintenance methods that take advantage of natural processes to create spaces that are water efficient, while providing abundant plant growth, good habitat, and an enjoyable place to be. The watershed approach captures, cleans, and collects rainwater to slow, spread, and redirect its flow in ways that reduce the need for other irrigation. The benefits of using a watershed approach include:
​

• improved habitat
• increased biodiversity
• pollution reduction
• flood control
• reduced nutrient leaching
• carbon trapping
• water conservation

How much rainfall do you get?

Every yard is different, but your average 2700 sq. ft. roof in the Bay Area can collect more than 25,000 gallons of water each year! You can use the USGS rainfall calculator to determine how much rain water falls on your roof in any given storm, simply by entering your home’s footprint dimensions (length x width) and the amount of rainfall measured by you* or reported by your local news station. During a storm that drops one inch of rain onto a half-acre lot turns out to be nearly 14,000 gallons of water! Rain barrels, ponds, swales, and filtration tanks are all different ways you can collect rainwater.

Where does that water go?

All too often, rain water falls on buildings, roads, and concrete, where it collects pollutants and debris, and carries them to our groundwater. Our garden plants never have the opportunity to soak it up. On the other end of the spectrum, rain water either floods an area, carrying away valuable topsoil, or it gets stuck in one place, where soil, plants, and organisms begin to rot. Using the watershed approach removes those problems by studying where water comes from, where it goes, and taking actions that redirect water flow to be more efficient and environmentally sound.


First flush and absorption areas

First flush refers to the first 3/4 to 1 inch of rain that falls after a dry period. This rain water contains higher levels of pollutants and debris than the rain that follows. Can you filter those pollutants out or redirect this water to less vulnerable areas? After that water is dealt with, how much permeable soil is needed to absorb your expected rainfall? First, you will need to know how deeply your soil absorbs water. You can determine this by going outside after a few days of rain and digging in with your shovel. How far down did the rain actually go? This number can help you determine how big of an absorption area you will need for the expected rain.


Example: You live in a 1,000 square foot house in San Jose, CA, where you receive an average of 15 inches of rain each year. Using the USGS rainfall calculator, you would discover that your house can collect 9,351 gallons of water in a year. To absorb all that water, you would need to divide the volume of water by 7.48 for a per foot absorption area. (There are 7.48 gallons of water in a one cubic foot of space.) This gives you 1250 square feet needed to absorb all that water, assuming that your soil absorbed water down to a depth of one foot. If it only went down 6 inches, the 1250 sq. ft. figure would have to be doubled. If you don’t have that much space, how can you prevent runoff? What if that’s not enough water?


What are other sources of irrigation water?

Be sure to check with your local municipality for laws regarding water collection (there have been countless wars started over water rights). You can collect water from your bath or shower, as it heats up, in a bucket. You may be able to redirect the outflow from your washing machine to irrigate ornamentals. Even the water left over from cooking pasta and vegetables makes useful water for the garden.


How much water do you really need?

There is no excuse for wastefulness when it comes to water. You might be surprised at how little water you and your garden actually need. Our household has reduced water consumption to only one-fourth of what it was three years ago and we get more production from the garden! This is possible by:

• reusing water
• inspecting and repairing leaky sprinklers (we stopped using them altogether)
• installing native and other plants that are more suitable to your microclimate
• improving soil structure with compost
• reducing evaporation with mulch
• collecting water from the roof with rain barrels
• getting rid of unused lawns (out front)
• providing plants with only as much water as they will actually use, when and where they need it
• sheet mulching to reduce competition from weeds
• watering early in the morning at ground level with drip lines and soaker hoses
• identifying areas with poor drainage and redirecting water toward areas that need the water

Other factors to consider when using the watershed approach:

• Where does water go when your soil is saturated?
• How much area is covered with impervious materials, such as concrete, and where does that water go?
• Are their slopes on your property that can cause faster runoff? Can they be terraced?
• Does your landscape have chronic problem spots?
• Are there any migratory birds, insects, or animals that you would like to provide for? (Monarch butterflies are one example.)

Start using the watershed approach in your yard by asking yourself these questions:

1. Where does rainwater currently go when it rains on your yard or garden?
2. Can you collect rainwater from downspouts in rain barrels or other containers?
3. Can you redirect rainwater to areas that can make better use of it?
4. Does flowing rainwater move topsoil when it rains and how can this be altered?
5. Have you installed plants that thrive in your microclimate?

What’s really nice about the watershed approach is that it takes advantage of natural processes that have evolved over thousands of years to work without any help on our part. Native plants and those suited to your microclimate require less care, which translates into less work, less expense, and a healthier environment.


Activity: Inventory your landscape’s water needs
​

1. Start by capturing a Google maps satellite image of your property. (You may want to print out a few copies - and color coding the information makes it easier to use)
2. Label as many plants as you can and learn more about their water needs. You may want to sort plants by water use: red for high, orange for medium, or yellow for low)
3. Label rain gutter downspouts and the route taken by rain water from those downspouts.
4. Label sprinklers, drip lines, soaker hoses, and other forms of irrigation.
5. Identify areas with poor drainage.
6. Use this information to find areas where water can be collected, slowed down, or redirected to reduce water waste and runoff.

Every drop of water that you are able to use more efficiently protects the environment and your bank account.

Vectors of infection

Bean mosaic is spread by aphids, mealybugs, and leafhoppers. While it sounds convenient, research has shown that using insecticides is not practical because it kills the beneficial insects who would normally feed on the pests. Once a plant is infected, it becomes a vector for disease, as well, and should be completely removed from the site. Infected plants should not be added to the compost pile.


Controlling bean mosaic

Prevention is the best protection when it comes to bean mosaic. Use these handy tips to reduce the likelihood of future generations of beans becoming infected:

• Remove nearby broadleaf weeds. The weeds may provide habitat for the virus and for the vector insects that carry it to your plants.
• Installing reflective mulch may repel insects. You can buy rolls of silver polyethylene from a garden store, or paint some cardboard with silver paint, or lay aluminum foil around your plants for the same results. Just be sure to remove reflective mulch before temperatures get hot or it can cook your plants!
• Buy disease-free seeds from reputable suppliers
• Buy resistant varieties (heirlooms are less likely to be resistant)
• Do not plant beans near clover, alfalfa, rye, or other legumes
• Rotate bean crops each year
• Start plants early enough that they reach flowering stage before aphids become a problem
• Treat heavy aphid infestations with neem oil or insecticidal soap

Bean mosaic is one of the most powerful arguments against using dried beans from the grocery store to plant in your garden. While they are perfectly safe to eat, there is no guarantee that they are safe to sow. Invest in high quality, guaranteed clean seeds from a reputable seller and then save the best seeds from your crop for replanting.

Beans are easy to grow. They improve soil structure, provide excellent food crops, and can look lovely in a landscape, as long as they are kept healthy.

Pumpkin pie, pumpkin pudding, pumpkin bread, and the ever-popular Halloween jack-o-lantern are all autumn favorites. But, did you know that most canned pumpkin puree is actually squash?


Being members of the squash family (Cucurbita), pumpkins and other winter squash share enough characteristics as to be indistinguishable according to the FDA. Huh. How about that? So much for truth in advertising. No matter. Growing pumpkins is rewarding and not nearly as difficult as you may think.


The story of pumpkins​

Pumpkins are native to North America. Early Native Americans grew pumpkins along with maize and beans in the Three Sisters Method. This sustainable gardening method combines the nitrogen-fixing ability of beans with the climbable maize (or corn), and the soil protecting, weed preventing shade provided by broad squash leaves. Ripened pumpkins were roasted over fires, baked in dirt ovens, parched, and boiled. They dried pumpkin flesh and used it as flour, and dried the outer shells to be used as containers. Pumpkin blossoms were added to soups and stews, and any seeds that were not saved for the next year’s crop were roasted for as tasty snack. I don’t see any reason why we shouldn’t be using this durable and attractive plant in the same ways in our own gardens.


How to grow pumpkins
Pumpkins are now grown everywhere except Antarctica, as human and livestock food, and for use as autumn decorations. Now, I love seeing those round orange signs of a good harvest on porches and patios, but it kills me to see them tossed to the curb, many of them never even opened. What a waste! Unopened pumpkins can always be donated to local food banks, if nothing else. Personally, I put my pumpkins to work for my own family. The easiest way possible, is to simply let nature take its course. You can leave a pumpkin in a suitable location to go through all the natural cycles and just leave it alone.

If you prefer a more focused effort, you will need seeds. It can start with a store bought packet, seeds from a friend’s pumpkin, or your own current pumpkin. Jack-o-lantern or not, I will eventually cut into my pumpkins. I can put this off for quite a while because pumpkins and other winter squashes, such as butternut, have one heck of a shelf life, if they are cured correctly. We’ll get to that in a minute.


Cutting open the pumpkin, you will find a treasure trove of seeds inside. I remove the seeds and separate them from the stringy threads that nourished them (my chickens love that stringy stuff!). I choose the fattest, firmest seeds for next year’s crop, placing them inside a folded towel to allow for air flow without sun exposure, until they dry. The rest are soaked in a brine and roasted for a family favorite. 


After temperatures have reached a steady 70ºF, those saved seeds are planted in hills, or mounds, of loose soil amended with aged compost or manure. The hills improve drainage and the soil warms more quickly. Pumpkins are very heavy feeders and their seeds are temperature sensitive. Each pumpkin plant can take up to 50-100 square feet, given the opportunity. You can also redirect vines along walkways, lawns, or fences. Plant 4 or 5 seeds 1” deep in each hill. If you have room for multiple hills, they should be spaced 4 to 8 feet apart. After your seedlings are 2 or 3 inches tall, select the best 2 or 3 for each hill and snip the rejects off at soil level. This causes the least amount of disturbance to young roots and important soil microorganisms. If you are growing pumpkins in rows, rather than hills, seeds should be planted 6 to 12 inches apart in rows that are 6 to 10 feet apart, thinning seedlings to one plant every 18 to 36 inches.


Caring for pumpkin plants​

It takes a lot of water to make a pumpkin. During fruit set, each pumpkin plant should receive approximately one inch of water per week. (One inch of water is equal to 0.623 gallons per square foot.) When watering, try to avoid getting the leaves wet, as this can promote fungal diseases. Mulching around pumpkin plants will help conserve water, stabilize temperatures, and reduce competition with weeds. Since pumpkins are shallow-rooted, it is not a good idea to disturb the soil. If you only have a small space, pumpkins can be trained up a trellis. Depending on the size of the fruit, you may need to provide hammocks as support. 


How to hand pollinate pumpkins
One common problem with pumpkins is insufficient pollination. You can pollinate your pumpkins by hand for a bigger crop. To hand pollinate, you must first learn the difference between male and female flowers. It’s not hard. Male flowers tend to open earlier in the growing season and they feature a stalk that emerges from the center of the flower called the anther. If you touch the anther and your finger comes away dusted in yellow, it is ready to use for hand pollinating. Simply cut the male flower off and remove the petals to create a “paintbrush of pollen”. Female flowers contain an ovary, which looks like a small ball at the base, outside of the petals. Male flowers do not have this structure. Once female flowers begin to open, simply use the anther paintbrushes to apply pollen to the nubby bits (stigmas) in the center of the female flower. If pollination is successful, the ovary and the base of the flower will begin to swell, ultimately becoming a mature pumpkin.

Pumpkin pests & diseases

The most common problem I have had with pumpkins are powdery and downy mildews, with an occasional bout of blossom end rot. Weeks will go by and the leaves will stay bright green and healthy and then, it seems suddenly, the leaves are covered with fuzzy white and gray areas, top and bottom, and production slows to a near halt. Pumpkins are susceptible to other fungal diseases, such as Verticillium wilt, root rot, damping off, and curly top, but I have not experienced any of those in my garden. Many insect pests also enjoy pumpkins. Crickets, earwigs, several types of beetles, stinkbugs, wireworms, whiteflies, thrips, nematodes, armyworms, spider mites, aphids, and, of, course, slugs and snails. Looking at this list, it’s a wonder that pumpkins grow at all, but grow they do!


Pumpkins are ready to harvest when the shell is firm and the stem is shriveled. After removing the fruit from the vine, allow it to dry, or cure, for a couple of weeks in a location with plenty of airflow and cool temperatures. Garages work nicely. After your pumpkin has cured, it will remain edible for several months.


Give pumpkins a try in your garden!

Poise and grace may carry us through difficult situations, but sometimes things just need to fall apart. Much like social disasters, there is far more going on in the garden than meets the eye when decomposition takes place.

Decomposition describes the way complex organic structures are broken down into simpler structures. When plants and animals die, all the processes that held them together and kept them functioning stop working and they become humus. The study of how things decompose is called taphonomy, from the Greek word for tomb.


Most of the mineral food enjoyed by your plants comes from humus, the plants and animals that have died. You probably already knew that, but did you know that the living things that speed decomposition actually reduce the amount of nitrogen in your soil as they feed?


Basically, there are two ways decomposition occurs: with the help of other living things (biotic decomposition) or through physical or chemical processes (abiotic decomposition). Now, you may think that this doesn’t apply to you as a gardener, but what about your compost pile? What is all that mulch actually doing to your soil as it breaks down? It’s really pretty amazing, so read on!


There are three basic stages of decomposition:

1. First, water either evaporates, causing dehydration, or, if there’s enough water in the environment, rot will set in. Rotting is the breakdown of complex structures by bacteria and fungi.
2. Next, local microbes and invertebrates, such as worms, snails, and sowbugs, start chewing on soft plant tissue, breaking it into smaller bits and transforming it into frass. In some cases, it is birds, voles, and even ourselves that breakdown plant material as we eat it.
3. Eventually, chemical changes begin to occur in the plant’s tougher, structural parts as other microbes start feeding.

This is why your compost pile works faster when you chop it up and flip it periodically. The cut edges provide points of entry for all those microscopic workers and the air helps the microbes breath. Warmer temperatures also speed up the process. Like us, those little helpers don’t move nearly as fast in winter! But, as they feed, they take the chemical elements that made up the plant and break them down into nutrients that are available to living plants. 


So what happens when I put straw mulch around my fruit trees?

Air, sunlight, and water will add their two cents to the decomposition process, but straw is pretty tough, so it will take some time to decompose. Local birds may grab a few bits and the sowbugs are sure to start feeding, but it is the microbes who will do the lion’s share of the work. 


The plants and microorganisms that feed on dead or decaying plant matter are called saprophytes. As the saprophytes feed, they poop out simple minerals that plants use and gummy substances that hold bits of soil together into aggregates. These aggregates improve soil structure by creating plenty of macropores and micropores. This means that water and nutrients will move through the soil more easily. These soil aggregates also improve aeration, drainage, water-holding capacity, and water infiltration rates.


As decomposition takes place, carbon dioxide is also released. This CO2 can end up in the atmosphere, or it may combine with water to form carbonic acid. Carbonic acid (H2CO3) works with other chemicals to break down rocks and pebbles in the soil, making those nutrients available to nearby plants.


What about the net loss of nitrogen?

It ends up that there is a delicate balance between the amount of nitrogen available to plants and the needs of the saprophytic bacteria and fungi that make those nutrients available. If you add a bunch of carbon (straw, leaves, kitchen scraps) to an area, the microbes will begin feeding and breeding like crazy. The only thing is, they also need nitrogen to live, so they will pull it from the soil, creating an initial nitrogen loss. Of course, over time, all of those nutrients will end up back in balance, supporting your garden, but that may take time that your seedlings simply do not have. This balancing act is called the carbon-to-nitrogen ratio. 


Ideally, you will want a 10:1 to 12:1 ratio of carbon to nitrogen. This means adding one pound of nitrogen for every ten pounds of carbon. If you are going to add a large amount of carbon to an area, it is a good idea to also add nitrogen. This keeps all the inputs for your soil microbes in balance as they improve your soil. Personally, I sprinkle blood meal (a good source of nitrogen) over an area, top that with aged compost (a good slow-release of many different nutrients), and then mulch with straw. The mulch keeps down weeds, stabilizes soil temperature, and, combined with the compost and blood meal, provides excellent nutrients and improved soil structure. It’s my way of tucking in my plants for our mild winters or when plants are stressed by too much California sun.


If you have access to a microscope, check out the various stages of decomposition to see what’s really going on down there!

Often yanked out as a weed, purslane is decidedly edible.

Common purslane (Portulaca oleracea) requires little or no care in our California gardens and landscape. Also known as pigweed, pursley, and fatweed, this prostrate spreading succulent is an excellent addition to salads and sandwiches, plus it makes for a refreshing snack as you work in the garden! The leaves and young stems are crisp, moist, and lemony, something akin to spinach and watercress. Common purslane is not to be confused with Winter purslane (Claytonia perfoliata), also known as Miner’s lettuce. The two plants are very different, aside from both being edible.


Purslane is filled with lots of good nutrients. It has especially high levels of omega-3 fatty acids. According to Mother Earth News, purslane contains, “six times more vitamin E than spinach and seven times more beta carotene than carrots.“ Purslane provides high levels of antioxidants and vitamins A and C, along with potassium, iron, and magnesium.


Purslane also contains pectin, which allows it to be used in cooking as a thickener (and helps reduce cholesterol). When overcooked, it may become slimy, like okra, so crushing the leaves is a good idea when adding it to soups and stews. If cooked lightly, purslane can also be used in stir fry dishes. That being said, oxalates are also present, so purslane should not be eaten by people prone to kidney stones.


While purslane is an annual, it is well equipped to reproduce without human intervention. According to Sonoma Master Gardener Stephanie Wrightson, a single purslane plant can produce “240,000 seeds, which may germinate after 5 to 40 years” so it is a good idea to monitor the plants for seed production if you want to get rid of purslane and you’re in luck if you don’t! Purslane seeds love freshly turned soil, as it brings them closer to moisture and sunlight.


While common purslane grows in a horizontal mat, you can also buy seeds for garden purslane (Portulaca oleracea) or golden purslane (Portulaca sativa). These plants are more upright in their growth (up to 18 inches tall) and the leaves are larger and more tender.


To grow purslane seeds, plant them 4 to 6 inches apart, only about 1/4 inch deep. Keep them moist until they have germinated and put out some mature growth. Once established, the leaves and stems can be harvested at any time. Purslane can also be grown in containers, indoors or out, and it makes an attractive windowsill garden addition. Frost will kill the current generation.


While I have never seen any pests or diseases affecting the purslane in my yard, there is a weevil, (Hypurus bertrandi), also known as portulaca leafminer that is known to attack purslane in California. There is also a purslane sawfly (Schizocerella pilicornis) that is found in California.


An interesting note: purslane harvested in the morning is crisper, while the same plant harvested in the afternoon is sweeter. Purslane can handle dry and irrigated locations. Personally, I encourage it under my fruit trees. The plants cover the ground, protecting it from erosion, other weeds, and water loss, while the shallow roots do not seem to interfere with the trees. This living mulch serves me well in the garden and in the kitchen!

Do you have purslane in your garden? Have a nibble and let us know what you think in the comments!

Mulch can be anything placed on top of soil to cover and protect it.


​Naked soil is vulnerable to erosion, weed seeds, compaction, and water waste. Mulching provides many benefits:

• Reduced water waste
• Temperature stabilization
• Reduced weed populations
• Reduced erosion and topsoil loss
• Improved soil structure and fertility

So, what makes a good mulch? 

A good mulch allows air and water to pass through easily, while blocking the sunlight needed by weed seeds for germination. Obviously, gravel fits that description, but do you really want to pick out all those rocks at planting time? Or, what about black plastic landscape cloth - doesn’t that do the same thing, without all the work? No, it doesn’t. Ultimately, the plastic will break down, allowing weeds easy access and adding chemicals to the soil. Instead, take advantage of natural processes and use plant-based mulches. They add nutrients and improve soil structure as they break down and they can often be found for free!

Straw/Hay - Local feed stores will occasionally offer free hay or straw that has gotten wet, making it unsellable. It still makes a great mulch, so long as it is spread while still wet. Wet hay bales have been known to smolder and burn, or even explode. Believe me, I speak from experience.

Compost - Compost that is placed on top of the soil becomes a highly effective, nutrient rich mulch.

Grass clippings - Grass clippings are a nitrogen-rich mulch, which may lead to temporary nutrient fluctuations. Don’t leave them in piles, however, as they will stink to high heaven and may spontaneously combust!

Leaves - Rather then sending deciduous leaves to the land fill every autumn, they can be used as an excellent mulch or added to the compost pile.

Pine needles - If you have a friend with a pine tree, they would probably be very happy to get rid of the needles. Pine needles are excellent mulch because they break down very slowly. Unfortunately, despite popular opinion, green pine needles only slightly alter soil pH and dried needles do not change it at all.

Chipped and shredded tree trimmings - Most tree trimming companies are happy to give away full or partial truckloads of perfectly good mulch. Just be sure to inspect the material for pests or disease before it gets dumped on your driveway! Coarse wood chips make an ideal mulch. They break down slowly, improving soil structure and feeding the soil microorganisms that make plant life possible.


How to apply mulch

​Mulch should be applied 2-6” thick, depending on particle size. Smaller pieces fit together more closely, so you don’t need as much as for larger bits. If weeds are a serious problem, or you are eliminating a lawn, it is a good idea to use a really thick layer of wood chips. Be sure to keep mulch several inches away from trunks and stems. If mulch is in constant contact, problems such as crown rot can occur.


As worms, beetles, weather and microorganisms breakdown the mulch, improving the soil, more mulch will need to be added.

Composting is the natural process by which organic materials are broken down, making them available to plants and microorganisms. It is a major component of pedogenesis, or soil creation. Without healthy soil, we begin to lose our food, water and air. Yeah, it’s kind of important.


More benefits of composting:

• Less biodegradable materials end up in landfills
• Improves soil structure
• Reduces water consumption
• Reduces compaction and the need for aeration
• Improves permeability
• Reduces the use of carbon fuels
• Promotes soil fertility
• Stimulates healthy root development
• Reduces erosion
• Reduces the need for chemical fertilizers

One of the nicest things about composting is that bacteria and fungi do most of the work for you! Other organisms, such as worms and insects, also pitch in to help. Now, it is possible to simply dump everything in a pile and wait for nature to takes its course. Eventually, there would probably be a nutrient rich soil amendment, but it might take years. It might also turn into a stinky, rotten mess. Follow these tips for successful composting in a reasonable amount of time.


Selecting a site for composting

• Place it close enough to be convenient, but not bothersome.
• Avoid locations that are next to a house or fence.
• Bins, drums or piles?
  • Some gardeners buy a bin or drum, but I think it’s a waste of money.
  • There are many DIY compost bin instructions available online.
  • Piles work for me just fine.
• The location can be on dirt or cement,  in shade or sun (If the compost pile is on dirt, that spot is going to provide some excellent growing in the future!)
• The ideal size is 3’ x 3’ x 3’ to 5’ x 5’ x 5’ (Smaller, and it won’t get warm enough; Larger, and it can’t breath)

Understand the process: Organic matter + air + water = compost

Organic matter* consists of yard and kitchen waste that has been cut into 2” or smaller sized pieces. Smaller pieces compost faster because there is more surface area for decomposers to reach. Organic matter is considered either “green” or “brown”. Green matter includes cut grass, pulled weeds, kitchen scraps and manure, and it is rich in nitrogen. Brown matter is rich in carbon and includes dried leaves, straw, and shredded newspaper. The ratio of green to brown is a major factor in how long it takes a compost pile to breakdown. “Hot” piles work fastest and use a 30:1 carbon-to-nitrogen ratio, while slower piles can have a 2:1 carbon-to-nitrogen ratio. If material is continually added to a single pile, it will slow the process. A better choice is to have 2 or 3 piles, at various stages of decomposition.


Decomposition is an aerobic process, which means it needs air. Air helps breakdown organic matter and those tiny workers need it, too! Air enters a compost pile by turning it every few days. [Read: good exercise]


Water is needed for the same reasons as air: it aids in decomposition and it keeps microorganisms and other decomposers alive. Keep the compost as damp as a wrung out sponge and avoid simply watering the top, as this tends to cause runoff. Watering as the piles are turned works the best. If the pile gets too wet, spread it out and let it dry, or it will rot


Temperature is another composting factor. As materials break down, especially the green ones, energy is released in the form of heat. If you’ve ever watched a big pile of freshly cut grass, you know exactly what I mean. Under the right conditions, a pile of grass clippings can burst into flames! (And it stinks to high heaven). Ideally, the right conditions will generate temperatures between 122 - 131 degrees Fahrenheit. If temperatures remain above 140 for at least 10 days, weed seeds and pathogens will be killed. If temperatures stay above 160, however, decomposers will die and the process will stop. Some people take their composting very seriously and monitor temperature. I don’t.


Because temperature is a factor, do not expect much out of a compost pile in winter. Material can still be added, or another pile started. In spring, the whole process will begin again. Also, if a area is especially hot or wet, cover the compost pile to maintain desirable moisture levels.


Compost is called “finished” when it is ready to use. Finished compost takes up 25-40% of the original occupied space, depending on its ingredients. Compost can be dug into beds before planting, a 2” layer can be applied over lawns as an amendment, or it can be used as mulch. Personally, I also add compost to the bottom of potted plants before adding high quality potting soil and my plants seem to like it a lot.


For those who do not have space for a compost pile, bin, or drum, try composting with worms! This is called vermiculture. Worm bins can compost an amazing amount of yard and kitchen scraps pretty quickly. Worms can eat their body weight in scraps every single day! Learn how to build worm bins and compost with worms at the UC Agriculture and Natural Resources page about worms.


Remember, composting is easy and it provides a powerful boost to the garden. Start composting today!



*Most recommendations warn against using meat, dairy, and grease in compost piles. Other people have no problems with it. Personally, I use the majority of my kitchen “waste” to make soup stock. The solids are then fed to my chickens. Whatever they don’t eat (along with what they did eat) ends up in the compost pile, bones and all. I have had no problems and my plants seem to appreciate the calcium.

Fertilizer is one of those things that falls under the, “Too much of a good thing is a bad thing” category. All too often, at the first sign of unhealthy plants, people grab a bag of fertilizer before checking for inhospitable soil conditions, unhealthy roots, irrigation problems, nutrient toxicities, and pest or disease infestation. ​

N, P & K

Most gardeners are familiar with the three numbers displayed on bags and boxes of fertilizer, but we’ll do a quick review, just to be sure. Those three numbers represent the percentage by weight of nitrogen (N), phosphorus (P) and potassium (K). Think about this for a moment. A 10-pound bag of 10-20-10 fertilizer contains 1 pound nitrogen, 2 pounds phosphorus, 1 pound potassium, and 6 pounds of filler. Yes, filler. If all your plants need is nitrogen, blood meal may be a better choice.

Plant nutrients

Plants use 16 chemical elements as food. Those elements include oxygen, carbon, and hydrogen, along with 13 mineral nutrients. Those mineral nutrients are broken down this way:
    Macronutrients
        Nitrogen (N) - leaf growth
        Phosphorus (P) - root, fruit and flower growth
        Potassium (K) - stem and cell growth
    Secondary Macronutrients
        Calcium (Ca)
        Magnesium (Mg)
        Sulphur (S)    
    Micronutrients
        Copper (Cu)
        Iron (Fe)
        Manganese (Mn)
        Molybdenum (Mo)
        Zinc (Zn)
        Boron (B)

Soil tests

Before applying fertilizer, invest in a good soil test. It’s worth it. And it’s a fascinating snapshot of what is really going on in the garden. Now, I don’t mean one of those over-the-counter test tube kits. Those are a waste of money, in my humble opinion. When searching for a soil lab, it is best to pick one near you. The east and west coasts have very different soils (ours is alkaline; theirs is acidic, for one thing). This means that different types of tests are used to analyze soil samples. 


I learned some surprising facts about my soil when I sent in a sample. Most important, I learned that my soil already has a ton of everything, except iron. Without iron, the plants weren’t able to absorb the abundance of available nutrients. Adding fertilizer would have been a complete waste of time and money. Instead, because I had the knowledge, I was able to apply a foliar (leaf) spray of iron and my garden plants had access to everything they needed! So, get your soil tested before adding anything.


Types of fertilizer

If you are like me and prefer a more natural approach, use compost instead of fertilizer. Since I raise chickens, composting is even more effective. Chicken poop is high in nitrogen, and practically anyone can raise hens or build compost. Yard and kitchen scraps that would normally end up in landfills can be transformed into nutrient rich compost that that also improves soil structure.


If you decide fertilizer really is necessary: READ THE BAG. Seriously. Federal law requires that specific instructions and useful information are printed on the container and for good reason. Follow directions carefully and wash your hands when you’re done. Technically, there is no chemical difference between nitrogen from compost and nitrogen formulated in a lab. Nitrogen is nitrogen. The difference lies in everything else. What are the fillers? What else is in the compost that plants need? Honestly, there’s a lot we don’t yet understand about how living things interact. I prefer to err on the natural side, just in case.


​For a hysterical read about the effects of too much fertilizer, check out Don Mitchell’s Moving/Living/Growing Up Country series.

If we say something is sustainable, we mean that it can keep going. Since agriculture and gardening are critical to our food supply, being sustainable is pretty darned important.


Until the 1980’s, food production was focused on the industrial production of single species (mono crops), using chemical fertilizers and pesticides, until the soil was exhausted. You can only do that for so long, before you run our of places to grow food. In 2002, at the International Society of Horticultural Science’s First International Symposium on Sustainability, it was agreed that sustainable agriculture and gardening were critical for the “well being of human societies”. ​

Sustainable gardening incorporates practices that reduce water, energy, time and chemical consumption, while producing food year-round and protecting the environment. These practices take the following issues into account:

• water availability and quality
• soil degradation
• energy consumption
• landfills and garbage disposal
• fire prevention
• wildlife habitat protection
• invasive plant and animal species

Design for sustainability

Whether you already have a garden or are just starting out, you can design a garden or landscape for sustainability. Native plants are always your best bet because they put millions of years of evolution to work for you, conserving water, reducing the need for chemicals, and freeing up your time. Lawns are notorious water wasters and, quite honestly, most of us are not British aristocracy. Other plants, such as oregano, yarrow, or clover, make excellent, low-growing ground covers that use less water and rarely, if ever, need mowing. 


These tips can help you create your own sustainable garden:

• Use plants that are suitable to your climate
• Get your soil tested before applying fertilizers
• Place plants with their mature size in mind, to reduce the need for pruning (and remember that mature trees can significantly cool your house in summer!)
• Use low-volume irrigation (drip systems, rain barrels, micro sprinklers)
• Ask your local water district for a free efficiency inspection
• Transform kitchen and yard waste into compost
• Install free mulch from local tree trimming companies
• Plant species, such as CA buckwheat or common yarrow, to attract and provide for beneficial insects
• Install porous hardscapes that allow water and gases to maintain soil health
• Pull weeds before they go to seed
• Identify pests before applying treatments and find out if there are more environmentally friendly methods

Recent heavy rains have brought much needed water to the drought stricken Bay Area, but one of my fruit trees was not happy about it. Take a look at the photo below to see how water pooled around the tree.

The drainage around trees with irrigation rings was fine. I can only assume that it was the cement curb around the tree that was at least partially to blame for flooding my poor little nectarine tree. At the same time, the drainage pattern was so significantly different, that I will have to explore other possible causes and remedy them. Rainwater generally moves down, due to gravity, and sideways, toward drier areas. The curb prevents that sideways movement. All that standing water can lead to crown rot, root rot, and many other fungal diseases.


What is porosity?

Porosity, or permeability, in the garden refers to the ability of air and water to move through tiny pockets in the soil. These tiny spaces are called macropores and micropores, depending on their size. Soil that is rich in organic material tends to have a variety of macropores and micropores that improve its porosity. Porous soil allows roots to reach out freely to find water and nutrients. In the Bay Area, we tend to have heavy clay soil that is made up of very tiny particles that leave few spaces in between. Porosity is measured as a percentage of spaces compared to the soil around them. Clay soil has a porosity of 40-60%, while sandy soils have a porosity of 30-40%.


What happens when it rains?

When rain starts to fall, or the sprinklers kick in, the soil is initially hydrophobic, causing runoff and urban drool. This is because the water is repelled, the same way a dry sponge allows water to run off the top, rather than being absorbed. Now, we all know that sponges are very porous. They have lots of holes that can hold water. That’s why we use them! 


Once the soil becomes damp, like a sponge, it can then hold a surprising amount of water. When all the pores are full, gravity then pulls the water downward into groundwater, where it is taken to creeks, lakes and oceans. That’s why it is so important to not overuse fertilizers, pesticides, fungicides or herbicides. All those chemicals leach into our water supply!


Porosity & plant health

As plants become saturated with water, tiny pores, called stoma, open wide and the plant starts panting in a process called evapotranspiration. Just as we can see steam when we breath on chilly days, plants exhale moisture along with other gases. When there is no water to be found, and the plant risks the other side of water stress, the stoma close, to hang on to every bit of moisture possible. When the ground gets muddy, whether from too much rain or over-watering, roots cannot breath and the plant can drown. In the case of my nectarine, I used plastic tubing to redirect the standing water away from the tree. That’s not something I want to do every time it rains, so I will use these methods to improve the porosity around the nectarine tree:

• Aeration - Using my soil test rod, I will remove cylinders of soil from around the tree.
• Cover crops - I will plant a deep-rooted cover crop to help break up the soil.
• Compost - This is the Number One best way to improve the porosity (and health) of any type soil. Since I raise chickens, there’s always plenty of compost!
• Mulch - I will apply a thick layer of mulch to encourage worms and other soil microorganisms.

If you see standing water after a heavy rain, these tips can help you improve the porosity of your soil and the health of your plants.


UPDATE (1/10/2017) After heavy rains, I was very happy to see that the soil around my nectarine tree is draining very nicely. It really is amazing how effective just a little mulch, compost, and cover crop treatment can change an area for the better!

Roly-poly, pillbug, doodlebug, or sowbug, whatever you call them, the more you know about these creatures, the weirder they get.


First, they are not really bugs. They are a type of crustacean, called a woodlouse. Our garden-variety woodlice are in the Armadillidium genus, making them cousins to armadillos! Like armadillos, pillbugs can roll up into a ball, and often do, when disturbed. Other woodlice cannot do this.

 
Even stranger than being related to armadillos, female woodlice carry fertilized eggs in a marsupial pouch, like a kangaroo! They can also reproduce asexually. If that weren’t enough, sowbugs breathe through trachea-like lungs in their feet! These fascinating creatures can live for several years, producing two or three generations each year. Each brood can include 30 to 80 offspring. In particularly rainy years, pillbugs can be a problem in the garden.

Woodlice prefer cool, dark, moist places - under planters, bricks, hoses, dense vegetation, whatever they can find. Having evolved from sea-going crustaceans, such as lobster and crab, water is critical to their survival. [Note: don’t eat them. Wikipedia says they taste like “strong urine”. I don’t know how they found out and I am certainly not going to try it myself!] 


Dead plant material is a woodlouse’s favorite food. This makes them very helpful in compost piles and soil aeration. They also eat stinkbug eggs! Unfortunately, they frequently eat ripe strawberries, lettuces and cabbages, and plants with fruits that lay on the ground, such as squash and melons. These pests can chew tender seedlings down to the ground in a single feeding! Most of this feeding is done in the evening and at night. Other favorite foods of pillbugs include zinnias, blue lobelia, verbena, alyssum, pansies, and cardinal flower.


While pesticides can be effective, there are better ways of controlling these pests. The best way to take advantage of the benefits, without the risks, is to reduce dark, moist hiding places, and to keep mulch and other dead plant material away from seedlings, until they are large enough to survive being gnawed by a woodlouse.

Any word that ends with ‘-cide’ means death to something. In the case of herbicides, it means death to some or all plants that it contacts.


Herbicides are chemical weed killers. Non-selective herbicides kill everything, while selective herbicides are, well, selective. Until the 20th century, cultural controls and good old fashioned elbow grease were used to rid an area of weeds.

Chemical warfare

Chemical warfare research from WWII determined that synthetic plant hormones and other chemicals could be used to kill many broadleaf plants. There are several chemical reactions going on when these chemicals are applied. Some grass herbicides work by halting cell production in the meristems (growth tips). Other chemicals starve plants by interfering with the production of amino acids or by halting photosynthesis.


Using herbicides can lead to several problems:

• Overspray can kill nearby plants
• An area may become unsuitable for planting for several years
• Weeds become resistant (and we do not)
• Chemicals may enter ground water, causing algae blooms and other environmental problems
• According to the Union of Concerned Scientists, there are some herbicides that may increase the risk of cancer 

Loss of biodiversity is another serious problem. Nature’s balancing act is delicate and the full effects of chemical use is not completely understood at this time. For example, Roundup (glyphosate) has decimated global Monarch butterfly populations and increased the use of pesticides that end up in our food and water.


Safer alternatives:

• Hand weeding
• Maintain healthy plants
• Mulching
• Good garden design
• Proper irrigation methods
• Install porous grout in cracks or apply clove or lemongrass oil

If you feel that you absolutely must apply chemicals in the garden, follow the directions exactly. Make sure it is the correct herbicide for the site and the weeds in question. Apply too much and the excess simply enters our water supply. You will also want to make sure that the weeds are in the correct life stage for the herbicide to be effective. If a chemical claims to be preemergent, it will attack germinating seeds. Postemergent herbicides attack growing plants and they work better on young plants. Postemergent herbicides can be foliar (leaf absorption), root, contact or systemic. Systemic herbicides are absorbed and spread throughout the plant.


Be sure to read product labels carefully and completely, and dispose of the container properly.

Have the pea plants in your garden turned white?


If you look at the photo below, you will see that new (uninfected) growth is bright green, as it should be. Everything else on the plant looks bleached. That bleaching is caused by a fungal disease known as Fusarium wilt.

Similar to Verticillium wilt, Fusarium wilt is a common vascular disease in which a fungus (Fusarium oxysporum) clogs vascular vessels. It’s pretty much the coronary artery disease of the plant world. In addition to bleaching, common symptoms of Fusarium wilt include chlorosis, stunting, damping-off, brown veins, necrosis, and premature leaf drop.


This soil pathogen is found worldwide and it is spread by water splash, tools, and infected seeds and transplants. Fusarium wilt enters a healthy plant when germinating spores (mycelia) stab at the plant’s root tips and any damaged root tissue. That’s where the really amazing stuff starts to happen!

Fungal life cycle

The Fusarium oxysporum fungus has no known sexual stage. Instead, it produces three different asexual spores: microconidia, macroconidia, and chlamydospores. Basically, the germinating spores (mycelia) inject themselves into a plant’s root system. From there, the mycelia move through the cells of the root cortex and into the xylem (a plant vein). Then, it starts producing the microconidia (asexual spores). The microconidia join the sap stream for a free ride to the rest of the plant. Eventually, there are so many microconidia that a vein is blocked. That’s when they germinate.


The vein blockage stops the plant form absorbing and moving nutrients, so the stomas close, the leaves wilt, everything looks bleached and it dies. As the plant dies, the fungus spreads throughout the plant and sporulates. [Cool word, right? It means “to produce spores”]

​
Plants affected by Fusarium wilt

Fusarium wilt attacks a variety of garden plants and the pathogens are specialized according to the victim. Fusarium wilt can attack peas, beans, and other legumes, tomatoes, tobacco, sweet potatoes, cucumber and other cucurbits, and even banana plants!


Fusarium wilt controls

Once a plant is infected with Fusarium wilt, there is nothing to be done except remove the plant and toss it in the trash. Planting resistant varieties in the garden can help prevent Fusarium wilt, but crop rotation is not an effective control method. This is because the chlamydospores can hang out in the soil for a long time. Some fungicides can be marginally effective. 


Since Fusarium oxysporum prefers heavy, moist soil, aeration and adding compost to the garden can bring more oxygen into the soil. This reduces the welcome mat effect for many types of fungus. Ensuring proper drainage is the best way to avoid this garden menace.

Crown rot symptoms

Signs of crown rot include rotted plant tissue at ground level, wilting, leaf drop, trunk discoloration and leaves that turn yellow or even red or purple. Established trees may ooze a dark sap around the infected area. Older plants may survive a few years, but young plants normally die quickly.


If crown rot is found in the garden, your best choice is to pull up the plant and discard it. In rare cases, a tree can be saved by pulling soil away from the trunk and cutting away diseased areas. Fungicides are ineffective in treating Crown Rot.


Preventing crown rot

Prevention is the best course of action in areas prone to crown rot. To reduce the likelihood of crown rot taking hold, use these preventative measures:

• Ensure proper drainage 
• Amend soil with organic matter and compost
• Plant trees properly, with grafting unions above ground  level
• Keep mulch at least 6” away from trunks
• Never allow sprinklers to spray tree trunks
• Rotate crops such as tomatoes each year

You may have recently spotted (or heard) a large metallic green bug buzzing around your yard. Green fruit beetles, or figeater beetles, are large, clumsy, metallic green pests.

My dogs and chickens love to chase green fruit beetles, and I am grateful. In the heat of summer, these pests fly in to lay eggs throughout my garden and landscape, taking a toll on my fig harvest. They also feed on apricots, nectarines, plums, grapes, pears, and tomatoes, as well as manure and compost. Generally, figeater beetles (Cotinis mutabilis), do not cause a lot of damage, but they can if enough of them converge on your garden.

(This one's for you, Sabrina!)

Sheet mulching is touted as one of the easiest ways to reduce weeds in your yard or to get rid of a water-hungry lawn and replace it with something more drought-tolerant. (Solarization is a more extreme method that can rid an area of many fungal diseases, as well as weeds.)

To sheet mulch an area, trim any current plant growth to the lowest possible height, water the area (to provide for soil microbes) and then cover the area with cardboard. Be sure you don't used waxed cardboard used to ship produce. Once the cardboard is in place, cover it with tree trimmings, which can be gotten for free from most tree trimming companies. The cardboard blocks the sunlight to the weeds, preventing further growth.

​Before you decide to sheet mulch, however, you need to understand that this is a temporary arrangement. Cardboard and newspaper attract termites and voles. Those layers also interfere with evaporation, percolation, and gas exchanges. They need to be removed as soon as the job is done.

​Instead of sheet mulching, I urge you to call your local tree trimmer and ask for a free load of wood chips. The chips will provide all the benefits of sheet mulching, without the problems. A thick layer of wood chips 94 to 12") also improves soil structure and encourages the growth of valuable soil microorganisms. For free.