This Coffee Tastes Like Dirt! It Was Ground This Morning.

Seattle loves its coffee, ensuring there are tons of used coffee grounds and stacks of burlap bags available all around town. Gardeners are the main beneficiaries of this surplus waste!

Used coffee grounds are a great source of nitrogen for your leafy plants and compost. You may notice that organic fertilizers include seed meal, which is nothing more than ground up seeds. Coffee is brewed from the seeds of coffee plants – making it seed meal too!

For a balanced compost, add some grounds to other nitrogen-rich “greens” (like fresh pulled weeds and grass clippings from lawns where pesticides or herbicides aren’t used), and carbon-rich “browns” (like fall leaves, ripped up newspaper and a little sawdust from non-pressure treated wood). There’s no exact recipe for compost, but about half greens and half browns by weight is the general rule. Compost materials should also have a good variety of textures to encourage air flow, so don’t just use fine materials like coffee grounds and sawdust. Mix them with other ingredients.

Many gardeners claim a light coffee mulch discourages slugs and other bugs from attacking their plants. The residual caffeine is repellent to some species, but apparently not earthworms. Gardeners also report that adding coffee grounds to soil feeds a profusion of earthworms. Your worm bin will benefit from occasional sprinklings of cooled moist grounds too, but don’t smother your workers with grounds! Keep a balanced bedding with other food sources.

If you mulch with grounds, remember they’re full of nitrogen – something fungus loves too. To prevent a fungal bloom, apply your coffee mulch thinly and not where it will remain soggy. A too-thick layer will also tend to shed water when the grounds dry out.

There is a lot of confusion among gardeners and chemistry dilettantes about the pH or acidity of coffee grounds. Though a cup of coffee is acidic, the used grounds are much less acidic, and certainly no more acidic than common peat moss soil amendments. If you have a small amount of cooled grounds from your morning coffee, you can safely spread them around without worrying about throwing off your soil’s pH. If you pick up a few bags of used grounds from Starbucks or another coffee shop, spread it around thinly or mix it well with plenty of compost material or soil. If you regularly apply lots of grounds to your garden, occasionally mix in a cup or so of garden lime or wood ashes from the fireplace. Coffee grounds are not recommended for house plants as trace salts may build up after repeated applications.

The best recommendation for using coffee grounds in your garden is to remember your mother’s admonition for moderation in everything. Don’t go crazy with coffee grounds, but as an amendment with compost and soil, you won’t go wrong recycling coffee grounds into dirt.

Copyright © 2007, Brian Ballard. All rights reserved.

Interbay Mulch

When you put your garden to bed for the winter, that doesn't mean nothing happens during the dark, cold, or snowy months. Left bare and exposed to the elements, important nutrients will wash away, and soil organisms will go dormant or even freeze to death.

There are many ways to over-winter your garden while at the same time improving the soil for a head start next spring. One way to invest in your beds was invented at Seattle's Interbay P-Patch: Interbay Mulch.

While similar to sheet composting or Lasagna gardening, Interbay Mulch attempts to bring critters responsible for decomposition all the way to the top layer of organic matter. The full distribution of organisms makes this composting method somewhat faster than sheet composting.

Making Your Mulch

Once your beds are cleared of this season's crops, create a mix of equal parts greens (grass clippings, coffee grounds, fresh chopped plants, composted manure) and browns (fall leaves, non-pressure treated sawdust, dry plant material, etc.) just like you would for a hot compost pile. Though it's tempting to use mostly browns, thinking there's plenty of time for them to break down, be sure you add enough greens for a balanced decomposition process.

Spread your mix in a good foot-thick layer (or more if you have the stamina) on your planting beds. Water the mixture well to wet it down, then cover it all with a layer or two of burlap bags. Wet down the burlap too (or soak the bags in water before placing them). The burlap keeps the mulch dark, damp and insulated so organisms can work all the way to the top of your batch.

That's all there is to it! During the winter, check your mulch every few weeks to be sure it's still slightly damp. You might also turn your mulch at least once during the winter.

Room and Board

Gardeners have experienced a few problems with Interbay Mulch. During the chilly winter months, mice or rats sometimes set up house in the mulch as it retains a bit of warmth under the burlap blankets. If you've incorporated kitchen scraps into the mulch, rodents may not even have to go far for food! You can minimize this problem by excluding food waste from your mulch, and checking under the burlap for rodents every few weeks.

Moist burlap also provides the kind of environment slugs just love! During your occasional winter bed checks, pick out any slugs and kill them.

After a few years of experience, several gardeners at Interbay have noticed that too much organic material can cause their beds to shed water in the dry months. Interbay Mulch may not be appropriate to use every winter. Next winter, plant a cover crop where you had mulch this year. Then rotate back to mulch the year after that.

In the Spring

By the time spring rolls around, your Interbay Mulch will be finished. A few weeks before you're ready to start planting, remove the burlap and turn the beautifully decomposed mulch into the soil. You'll notice a better response from your vegetables and flowers next year as your investment this winter pays off!

More Reading

Here are two great articles about Interbay Mulch on the web. Read them for a more detailed history and additional recipes.

Interbay Mulch at GardenWeb

How to bake a batch of compost at The Christian Science Monitor

Copyright © 2003 Brian Ballard. All rights reserved.

Compost Q&A

Here are some compost questions from astute readers.

Q. What do we do with garden waste that isn't applicable for chopping up and putting back in the garden, like sticks, raspberry shoots, noxious weeds and the like?

A. Believe it or not, you can put most any plant material in a hot compost pile! Temperatures in piles I've described here can reach as high as 160 degrees F. That's enough to kill most bad bugs, weed seeds, and pesky roots. However, our reader is right: some stuff just should not be put back in the garden, especially plants suffering from viral infections. Bag infected plants and throw them away with your regular household trash. Any old wood (like stakes or raised bed boards) should also be thrown away as they'll simply take too long to compost.

Q. Are there 'manual' options to using a chipper/shredder? It would be nice to know if one could get garden waste and "browns" ground up nice and fine like the shredder does, without messing with a machine. Manual chopping doesn't really do the trick.

A. Mercifully, it's not necessary to chop everything super-finely for compost. If you can get your plant material chopped to about 3" sections or shorter, and bruise the tougher stuff, then enough critters and fungi will get access to break down the material. I like to step on sunflower or corn stalk sections, partially rotten onions or garlic, and tomatoes or other fruit to bruise or crush them first.

Q: I have been chipping away at a stump in our backyard and would like to know if I can incorporate this wood in my soil or worm bin?

A: Though the individual chips might be too large for a worm bin, you can certainly use the chips as mulch on top of the soil, or incorporate them into your soil. A few chips in the soil are fine by themselves, but if you add a lot of chips all at once, they will steal nitrogen from the soil as they break down. In that case, add some composted manure at the same time to provide extra nitrogen.

If you want to add the chips to compost, treat them as a brown and balance them with greens (lawn clippings, vegetable food scraps, coffee grounds, tea leaves, etc.) Be sure the chips are pretty small (about 1" across). Otherwise they'll take too long to break down.

Q: I am building leaf mold and have a variety of leaf types in bags. Are there any particular leaves that are not good for creating leaf molds?

A: Leaf mold is essentially slow compost made of just leaves. It's used in similar ways to compost, and also for starting seedlings.

Most leaves are fine for creating leaf mold. It's better if you can chop them with a mower or leaf shredder first, but starting with them whole is OK too.

You might want to exclude pine needles or large, waxy leaves like those from magnolias, hollies or rhodies simply because they take too long to break down. If you want to include these types of leaves, definitely chop them first.

Some gardeners are suspicious that leaves from certain tress will harm their compost or leaf mold. I couldn't find any definitive studies to back that up. The primary theory seems to be that, after enough decomposition, any natural poisons are broken down enough not to be a problem.

Here's some more info on making leaf mold: Leaf Mold FAQ at GardenWeb.

Copyright © 2003 Brian Ballard. All rights reserved.

Common Compost Problems

Here are some common composting problems and how to solve them. Don't worry - you can't do any permanent damage to your compost!

Pile Won't Heat Up

Once your compost reaches maturity, it won't heat up very much between turnings. But if you've just made a new batch and it doesn't heat up after a few days, there could be a few reasons.

You may have used too much brown material - in this case, add more greens like fresh grass clippings, used coffee grounds, or composted chicken or steer manure.

If your pile is too dry, add enough water as your turn it so it's as damp as a wrung-out sponge.

If your pile is too small, it won't have the critical mass needed to retain heat. Make your batches in one of the 3'x3'x3' wooden bins at Interbay.

Heat loss will be faster in the winter so you should cover your batch with several layers of burlap. The wooden sides on most bins at Interbay also help insulate your compost.

Larger Items Don't Break Down

Larger sticks and branches take a very long time to break down. Sometimes sticks interfere with your ability to turn the pile easily. If you can, use pruning shears or long-handled loppers to cut sticks into small sections. Otherwise, exclude large woody items from your mix.

Bugs!!!

Not all bugs in your compost are bad. Some bugs help break down large plant material so smaller critters can help with the decay process. Pillbugs (also known as roly polies) and sowbugs look like tiny armadillos and help chew up rotting material. Don't kill them. (Here's some trivia: The difference between sowbugs and pillbugs is that pillbugs roll up when frightened, but sowbugs can't roll up.)

Any big fat white grubs you might find in your compost are probably beneficial and should not be killed.

Fruit flies are attracted to, and breed in, exposed food scraps or fruit. Cover any food scraps or fruit with a layer of dirt or finished compost, or dig them deeper into pile so the flies can't reach them. Don't just throw them on top.

Though ants in your pile don't necessarily help or hurt the decomposition process, they probably signal that your pile is too dry. Add water to your pile as you turn it. The ants should be gone the next time you're ready to turn.

Slugs just love the moist, warm environment of a fresh compost pile. I often find them sticking to the burlap covering as I remove it to turn a batch. Pick out any slugs or put the burlap on the ground and squish the slugs.

Plants Sprouting

If you have rootstock or stems that seem to be sprouting in your pile, be sure to chop them to 3" sections or shorter. I have this problem mostly with mint roots. A hot pile should kill most rootstock.

If seeds are sprouting in your compost, be sure your pile has enough green material and moisture to heat up and kill seeds. Seeds usually sprout in slow, cold compost piles that take a long time to break down. Turn any seedlings under before they can set seed.

The Pile Smells Bad

There are a couple of reasons why your pile might stink. If it smells like ammonia or urine, you've got too much green material. (You're also losing valuable nitrogen!) This usually happens when you've added too many grass clippings. Add more brown material like fall leaves as you turn your pile.

If your compost smells like rotten eggs, then there are anaerobic bacteria in action producing hydrogen sulfide. Your pile needs more oxygen, and potentially less water. Turn your pile to introduce oxygen, and don't add any more water. Be sure to cover your bin with piece of plywood to prevent rain from soaking your compost.

Animal Pests

Bury food scraps or fruit under dirt or more compost to keep raccoons, rats and mice away. Covering your bin will also keep larger animals out. Rodents like to bed down in warm compost. Catch any rats or mice you can and drop them into a bucket of water to drown them. Don't set a mouse or rat free: they will multiply to dozens in a few months!

More Reading

Cures for Common Compost Questions at Organic Style

Composter Problems at Quinte Waste Solutions

Compost Problems at REAPS

Guide To Home Composting by Ann Costa at GAIAM

Backyard Composting Problems and Solutions from Washington County, Minnesota

Large C Shaped Grubs In Compost Pile at GardenWeb


Copyright © 2003 Brian Ballard. All rights reserved.

Getting Creative with Compost Ingredients

There's no special trick to successful composting other than ensuring a good mix of greens and browns. But there is an endless list of things that might be good -- or might be wrong -- to add to your compost.

The Good

Though potentially off-the-wall, these items can actually increase the overall benefits of your compost:

• Clay - Soil should be a good mix of organics, sand and, yes, even clay. The clay in dirt can even help capture nitrogen (as ammonia) before it escapes from your pile. (Don't add modeling clay.)


• Egg shells - These add calcium to the soil. (Don't compost rotten eggs.)


• Granite dust or greensand - This adds several trace elements. You can get granite dust at tombstone manufacturers. (Greensand is just a term for rock dust.)


• Hair - This sounds icky to me, but human and pet hair contains lots of nitrogen and composts nicely I hear.


• Junk mail - This is the most satisfying thing to tear up and throw in a pile! (But see glossy paper below.)


• Oyster shells - Either whole or preferably crushed, these add calcium.


• Seaweed - Seaweed contains lots of nitrogen. Wash it down first to remove salt.


• Soil - Some gardeners like to jump-start their compost by introducing extra organisms from soil. Though all organisms needed for decomposition already exist on plant material, adding a few shovels-full of soil can't hurt.


• Wallboard or drywall - Crumble it up as much as possible, and don't over-do it! Drywall is made of gypsum, which includes lots of calcium.


• Wood ashes - Wood ashes from non-pressure treated wood are high in potassium and can be used sparingly in compost. Don't use more than one or two shovels-full per batch since ashes are very alkaline and will disrupt the pH of your finished compost. (But see below for coal or BBQ ashes.)

The Bad

These things can go into compost if you're really, really good at composting, but the average gardener should avoid them:

• Dairy products - Same issues as meat (below).


• Diseased plants - Your pile would have to get awfully hot to kill all viral pathogens. Bag diseased plants at your plot and take them home for disposal.


• Fat or lard - Same issues as meat (below).


• Human urine - Though urine from a healthy person is sterile and contains lots of nitrogen, don't include it at our community garden. You can give it a try in your home compost if you must.


• Meat scraps - It takes a very specific set of conditions to safely decompose meat or dairy products. It's very hard for the average gardener to reproduce these conditions.

The Ugly

Strictly verboten! Never ever, ever put these things in your compost. At best they won't decompose, at worst they may cause disease in humans!

• Animal urine, feces, or litter - Cat feces in particular can contain parasites that cause brain damage in toddlers, infants, or unborn children. (Pre-composted horse, cow, rabbit, chicken manure or manure from other vegetarian animals is fine to add to your compost.)


• Coal ashes - These ashes contain harmful chemicals, even after burning. Don't use BBQ grille charcoal ashes either.


• Glossy paper - Don't compost glossy paper, catalogs or magazines. They include special clays and inks that aren't the best for your soil. Don't compost paper with colored ink either.


• Human feces (including diapers) - Leave it to the city to try to figure out how to deal with your poop! It can contain all kinds of viruses, bacteria and other diseases like dysentery, e. coli, and cholera. Even composted human waste from municipalities should never be used on food crops.


• Metal, Plastic or glass - These items will simply never decompose. Broken glass in the soil is obviously dangerous to gardeners.


• Pesticides, herbicides or fungicides - These will kill the very organisms you're trying to encourage in your compost!


• Petroleum products - Liquid petroleum products will poison the soil and groundwater. One measly pint of gasoline can contaminate 750,000 gallons of water.


• Pressure treated wood or sawdust - Pressure treated wood contains cyanide and/or other chemicals that kill beneficial soil organisms.

More Reading

Lists of other things you can or should not put in your compost:

Compost Ingredients at MasterComposter

All About Materials by Steve Solomon

What can I compost? at the HDRA

Materials for Better Composting at the Chicago DOE


Copyright © 2003 Brian Ballard. All rights reserved.

What Not to Compost

As easy as composting with nitrogen-rich "greens" and carbon-rich "browns" can be, there are some things you don't want in your compost. Most ingredients you can collect locally are perfectly safe, but knowing some minor details will help prevent a batch of contaminated material from ruining your garden.

Popular "greens" include grass clippings, coffee grounds, herbivorous animal manure, kitchen scraps, freshly pulled weeds and other plant debris.

Scraps or grounds from just about anything a person would eat or drink can be composted without worry. However, don't try to compost meat, dairy products or very oily foods (like shortening). They won't break down in the regular gardener's compost.

If you collect grass clippings from your own or a neighbor's yard, be sure no weed killers, pesticides, weed-n-feed type fertilizers or other herbicides were used on the lawn in the past year. Clippings from lawns treated with a basic N-P-K or even iron-based moss control fertilizers are fine, even if they're not organic. (But don't use moss control lawn fertilizers directly on your garden.)

If you want to compost animal manure, be sure to only use manure from animals that eat plants, like cows, chickens, horses and rabbits. Be sure the animals weren't treated with hormones or antibiotics, which can really disrupt the life cycle of soil organisms. Don't use manure from meat-eating animals like cats, dogs or humans. Feces from carnivorous animals can contain dangerous bacteria, parasites, and even viruses.

If you make a hot compost pile that heats up to 140-160 degrees F, you can compost most weed seeds. But if you make cold compost, avoid weeds that have gone to seed. You should also avoid any plants infected with blight, fungal wilt, club root, viruses or other diseases. Throw those plants away in your regular household trash.

If you live near a lake, you may have thought about composting that pesky, feathery water weed milfoil (Myriophyllum sp.). However, studies show that milfoil is good at sucking up toxic heavy metals; something you don't want in your garden.

Easy to find "browns" include fall leaves, sawdust, paper or straw bales. If you compost sawdust, be sure it didn't come from pressure treated wood, a manufactured wood product (like oriented strand board, particle board, etc.), or from wood that had finishes like paint, deck stain or lacquer applied.

You may have heard rumors that hickory leaves are bad for compost, or that oak leaves make compost too acid, but don't believe them. You can even use a shovel-full or two of wood ashes (but not barbeque or coal ashes) in your compost.

Most newspaper, office paper, cardboard, and junk mail can be composted, but don't compost glossy magazines. Remember that paper is very dry, so be sure to dampen it well when adding it to your compost.

In the fall and winter you can generally find bales of straw that are tempting to use in compost or as winter mulch. However, Washington has historically had a problem with a persistent herbicide called clopyralid (klow-PEER-uh-lid). Many farmers use clopyralid on hay, grains and other crops to kill weeds, but it remains in the soil, passes through grazing animals, and survives even the hot composting process. It will then frizzle your broadleaf plants. If you are offered bales of hay or straw, be sure to ask if there's any chance clopyralid was used before you accept them.

Copyright © 2005 Brian Ballard. All rights reserved.

Save Browns for Spring Composting

Just as Seattle gets too much water in winter and not enough in summer, compost materials can be difficult to balance across the seasons. Spring brings us too many "greens" while fall brings us too many "browns" for a balanced compost pile. The solution is to save some browns now to use next year's compost. Unlike "greens" which tend to get stinky if you try to store them, browns will patiently wait until you're ready for them.

When autumn leaves start falling, offer to rake your neighbor's lawn, or collect leaves from local side streets. Get your kids or grandkids into the act! Collecting leaves will be less messy if you get a head start on the rains, but even wet leaves will store fairly well.

If you have an out of the way location that won't be unsightly, store your leaves in plastic garbage bags. If not, simply pile the leaves on your garden plot after harvest time. Cover the pile with burlap weighted down with stones to keep your leaves from blowing away. You could even build a wire cage at your plot to store more leaves.

Some P-Patches make arrangements with the city to deliver leaves cleared from public streets or parks. If your P-Patch has enough room to store lots of extra leaves, contact the P-Patch office about setting up delivery.

When spring finally rolls around, mix your saved leaves with fresh grass clippings, coffee grounds, and other "greens" to start a batch of compost. If you keep the leaves a year or more, they'll eventually break down into great "leaf mold" that you can use to start seedlings or to mulch your garden. Don't let the word "mold" scare you – that's just the term for old leaves that have broken down to the consistency of soil.

Copyright © 2004 Brian Ballard. All rights reserved.

Preparing Your Garden for Winter

In a few months, you'll be putting your beds to bed for the winter. But that doesn't mean nothing happens during our dark, rainy months. Left bare and exposed to the elements, important nutrients will wash away, and soil organisms will go dormant or even freeze to death.

There are many ways to over-winter your garden while at the same time improving the soil for a head start next spring. Here are three suggestions that you may want to try (or even try each suggestion in a 3-year cycle.)

A Variation on Sheet Composting: Interbay Mulch

Once your beds are cleared of this season's crops, create a mix of equal parts "greens" (grass clippings, coffee grounds, fresh chopped plants, composted manure) and "browns" (fall leaves, non-pressure treated sawdust, dry plant material, etc.) just like you would for a normal compost pile.

Spread your mix in a good 12-18 inch layer on your planting beds. Wet down the mixture well and then cover it all with a layer or two of burlap bags. The burlap keeps the mulch dark, damp and insulated so organisms can work all the way to the top of your compost material. You can pick up free burlap bags on Wednesdays and Fridays at the Tully's loading dock at the south end of their building on Airport Way (the old Rainier brewery).

This winter, check your mulch every few weeks to be sure it's still slightly damp (and that rodents aren't using it as a home). Turn the mulch once on a rare sunny January day to help even out decomposition. By the time spring rolls around, your Interbay Mulch will be finished. A few weeks before you're ready to start planting, remove the burlap and turn your beautifully decomposed mulch into the soil.

Cover Crops

Winter cover crops benefit your soil as they grow and when you turn them under in the spring.

There are basically two types of cover crops: legumes that add nitrogen, and grasses that break up compacted soils and mine minerals from deep down. Nitrogen-fixing plants like crimson clover, vetch, field peas, or fava beans will help capture nitrogen from the air. Cereal rye, winter wheat or other grasses won't capture nitrogen as well as legumes, but their long fibrous roots help break up heavy clay soils. Grasses also mine essential minerals from deep down in the soil where other plant roots don't normally reach. Interplant grasses with legumes to help support the sprawling habit of vetch or field peas.

Plant your winter cover crops now. Better nurseries will a selection of seed mixes. You should even sow cover crops amongst any plants you haven't harvested yet. In May, turn your cover crop under several weeks before you're ready to start spring planting.

Winter Gardening

There are many crops that flourish in the cooler weather of fall, or even prefer a good chilly winter to get a head start on spring. You can start lettuce, arugula, cabbage, mustard, radish, beets, and snow peas now for late fall harvest. Try a cold frame or cloche for continuous harvests of greens through all but the most severe Seattle winter. October is the time to plant garlic or shallots to give their root systems to prepare for spring growth.

Copyright © 2004 Brian Ballard. All rights reserved.

Composting for Beginners

It's easy to make a batch of compost your garden will absolutely love!

Compost is decomposed plant material that helps improve your soil by adding organic matter. It helps soil retain water and provides nutrients in a form plants can use easily. Beneficial fungi and microbes in compost also help your plants absorb water and nutrients from the soil. The process of making compost is actually a speeded-up version of what happens naturally on the forest floor or prairie.

Compost starts with equal portions of "greens" and "browns". Organisms that break down plant material use carbon from browns for energy, and nitrogen from greens as food. Typical greens are: fresh grass clippings, chopped garden debris, coffee grounds or manure. Some browns are: fall leaves, straw, wood chips or sawdust (but don't use chips or sawdust from pressure-treated wood). You should be sure grass clippings come from lawns that were not treated with pesticides or herbicides.

Hot Composting

Hot composting is a method that creates compost very quickly. The bacteria that help break down plant material generate enough heat to raise the temperate to as high as 140-160 degrees. This kills most weed seeds and pathogens. A critical mass of at least 3'x3'x3' is needed to really get the decomposition process going.

To begin a batch, first find or build an empty compost bin. Many P-Patches already have bins just waiting for you! Gather and mix equal parts of greens and browns. Fill your compost bin to the top with this mixture, but don't overfill it and never compress the ingredients to try to make them fit. That squeezes out needed air.

As you transfer your mix to the bin, add enough water to dampen it well, but don't drench it. The fungi, microbes and other critters responsible for decomposition need water and oxygen to live. Too much water pushes out all the oxygen, leaving you with a smelly mess! If the batch is too dry, the composting process will slow down or stop. Your compost should be about as damp as a wrung-out sponge.

Cover the top of your batch with a few burlap bags to help retain moisture. Also cover the bin with a piece of plywood to keep out rain and sun.

Tending your Compost

After a few days your new batch of compost will heat up as bacteria start munching away at plant material, consuming oxygen in the process. Fungi will also feast on the fresh mix. These microbes and critters need air to do their work. About once a week, add more oxygen by turning your pile into an empty bin, or if you only have one bin, remove the contents and then put them back in. Try to move the stuff from the top to the bottom, and vice versa. As you turn, add a little water if the mix appears too dry.

Your batch will seem to shrink as the ingredients settle and rot. I like to top off the bin with more fresh mix the first few times I turn a batch.

Your hot compost is finished when it has mostly stopped decomposing, does not heat up between turnings, and looks and smells like dark soil. The initial ingredients should be unrecognizable in the finished product. In summertime, a batch takes about 6 weeks to finish. In winter, it may take as many as 12 weeks. So plan ahead for planting or transplanting time.

As you might have imagined, collecting ingredients for hot compost all at once, then turning the whole batch every week for 6-12 weeks can be tedious and backbreaking work. There's got to be an easier way -- and there is! It's known as cold composting.

Cold Compost

Any dead plant material will eventually rot back to soil. It may take weeks, months, or even years. The only question is how long you're willing to wait, and how much effort you're willing to add to speed up the process. The process where you add plant material as it becomes available (rather than all at once) is called cold composting because the ingredients don't heat up.

You don't need a bin for cold compost -- you can start a pile in a corner of your garden. As you have plant material to get rid of, just add it to the top of the pile. You can chop material by hand, or just throw it on whole. If you find that you have a lot of fresh plant material to add at once, it wouldn't hurt to add some extra browns. The same balance of greens and browns technically still applies to cold compost piles, but you usually don't have so many greens to add at once that restoring the balance becomes a necessity.

Your cold compost will be ready to use in 6 to 12 months. To get to the good stuff, remove the top layer of material that hasn't decomposed yet. Use that un-rotted material as the base for your next cold pile.

Since cold compost doesn't heat up to kill diseases, seeds and rootstock, you will need to be a little more careful about what you put in a cold pile. Don't add weeds that have gone to seed, diseased plant material, persistent roots from berries or vines, or vegetables like tomatoes or potatoes that may sprout in the wrong places.

Trench or Pit Composting

If you don't have a compost bin handy, or don't have room for a cold compost pile, why not try composting underground?

In trench or pit composting, ingredients are buried in holes or a long trench and covered with soil. When you anticipate you will have lots of garden debris to get rid of (like at harvest time), dig a round hole or a long trench between planting rows about 8-12" deep. As you accumulate green material, chop it and mix it with some browns like fall leaves. Drop the mix into your holes or trenches until they're about half filled, then cover it with the original soil you dug out.

It's important not to bury the plant material too deeply since most biological activity occurs in the top 12" of soil. Some gardeners recommend rotating your open and cooking trenches with plantings in a 3-year cycle. However, each pit or trench should be ready to plant over in a few months. If you wish to plant sooner, try peas or beans since they have shallow roots that won't be damaged by the rotting process happening deeper down, and because they help trap nitrogen that might otherwise escape from the decomposing material.

Sheet Composting

Sheet composting is easier than trench composting because there's no digging involved.

Start your sheet compost with a mix of equal parts greens and browns. I prefer mixing the ingredients thoroughly, but you can use several 2-3" layers of greens and browns if that's easier for you. Spread your mixture in an 8-12" overall layer and water it down. You can cover the mixture with burlap bags and wait a few weeks for decomposition to begin, or you can plant directly in the new mix. The layer of materials won't be thick enough to retain heat, so seeds or roots won't be damaged. You can also plant a cover crop over the compost materials. Nitrogen-fixing covers like crimson clover, vetch, or fava beans are the best since they will help capture nitrogen released in the decomposition process. Rye or other grasses won't capture the nitrogen as well as legumes will.

Using Your Compost

Compost acts as a slow-release fertilizer and you can add it to your garden at any time. Before planting in spring, dig lots of finished compost into the soil. As plants grow throughout the summer, mulch between rows with it every few weeks (but leave a little space around plant stems). In the fall, add compost before sowing a cover crop. If you cover your beds in the winter, add compost to let it age well before spring returns.

Copyright © 2004 Brian Ballard. All rights reserved.