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.

Have a Tea Party with Your Veggies!

Here is an interesting way to use your compost in a foliar application: compost tea. Many gardeners swear by its affects in perking up their plants!

What is Compost Tea?

Compost tea is a small amount of compost steeped for a short time in water, much like brewing tea from tea bags. The result is a rich solution containing both beneficial organisms and nutrients that you use when watering or to spray on leaves.

What are the Benefits of Compost Tea?

I originally thought the benefit of compost tea was simply as an organic replacement for water-soluble fertilizers like Miracle Gro or Peter's Plant Food. It turns out that compost tea is actually much more than a mild fertilizer. It also helps inoculate your plants against disease by introducing beneficial bacteria and fungi to the soil or leaves. The process of making compost tea creates an environment where beneficial organisms flourish at the expense of harmful ones.

Bacteria and fungi are very important in the soil, helping roots absorb water and nutrients. These organisms are also important when present on leaves. Spraying plants with compost tea helps control various mildews, molds, blights, and wilt diseases. The theory is that the beneficial organisms compete with the bad ones for food and space. They may even actively kill harmful organisms by eating them or creating natural antibiotics.

How Do I Make Compost Tea?

Compost tea is relatively easy to make from finished compost. Simply fill a 5-gallon bucket about 3/4 full with room temperature, chlorine-free water (either let tap water sit out for a day, use rainwater, or dip some water from a pond or stream.) Then add one shovel-full of fresh compost and stir. You can also use cheesecloth or another loose fabric to hold the compost as you steep it.

Let the mixture sit overnight (stir it occasionally if you're around). When you return, strain the top half of the liquid through a screen or cloth and spray it on plant leaves or water with it. You must use the tea soon after brewing it; otherwise oxygen in the water will be depleted and the beneficial organisms will die or go dormant.

Oxygen-loving (or aerobic) bacteria and fungi are generally helpful. Anaerobic organisms (those that can live with no oxygen) are usually not beneficial, can cause disease, and just plain stink! If you can't use your tea within 12-18 hours after starting it, you will need to aerate it to add oxygen. You can do that with an electric sump pump to circulate the liquid, or better yet by pumping in air. You can use a regular aquarium air pump to oxygenate the tea.

If you aerate your tea, you'll get the best results if you use it within 1-3 days. If you need to keep your tea for longer than that, add a cup of un-sulfured molasses (or other sugar source) every few days to make sure there's enough food to satisfy your growing colony of beneficial organisms.

After using your compost tea, add the remaining solids back to your compost pile, or mix it into the soil.

Never use bad-smelling compost tea. That's a sure sign there are too many nasty anaerobic organisms lurking in it. If your tea smells like sewage, aerate it for a day or two until the smell goes away. (However, you can use your tea if it simply smells yeasty. Foam that may form on top of your tea is not bad for your plants either.)

More Reading

Here are some compost tea resources and recipes on the web.

Compost Tea Basics at GardenWeb

Compost Teas for Plant Disease Control at ATTRA

Brewing Compost Tea by Elaine Ingham

Compost Tea at PA EPA

Compost Tea by Doug Green


Copyright © 2003 Brian Ballard. All rights reserved.

Dealing With Garden Debris

Every autumn, you begin harvesting bumper crops of vegetables! With that harvest, you'll have lots of extra plant material to get rid of. Here are some helpful tips on what you can do with your green debris.

The best way to get rid of your extra plant material is to chop it and return it to the soil, either by burying it directly in your garden beds or by starting a compost bin. You can also lay the chopped material between rows of plants, or dry it in your paths.

Some plant leaves can simply be shredded by hand. Stems and vines can be cut up with a pair of small clippers. Larger items or heavy stems can be chopped. Machetes, sugar cane knives, cleavers, and hedge clippers work fine for chopping. Find the tool that works best for you. Use a scrap of old lumber as a chopping block.

If you have a large volume of debris, why not start a compost pile? Mix your chopped green material with fall leaves that are plentiful around harvest time. You might also donate your chopped greens to a fellow gardener who is making a compost pile.

Copyright © 2003 Brian Ballard. All rights reserved.

When Your Garden Sleeps, It Dreams

This winter it may seem nothing is happening in your garden. Biological activity slows down in the colder months, organisms go dormant or migrate deeper into the soil, cool season weeds like chickweed get their first footholds, and rains wash nutrients and important minerals away. You don’t have to be a helpless observer of this hibernation. Use the winter months to rebuild your soil.

Once your garden is done for the season, clear out the last of your annual plants saving them for compost. Reserve a small part of the garden for your fall and winter greens and for planting garlic cloves in November. Cover the rest of your soil with a nice layer of compost materials about 8-12 inches deep. Be sure to use both “greens” (grass clippings, coffee grounds, fresh chopped plants, composted manure) and “browns” (fall leaves, non-pressure treated sawdust, dry plant material) in the mix.

A variety of amendments help replenish the supply of important minerals. Agricultural lime is a good source of calcium, and dolomite lime also includes magnesium. Calcium helps plants build cell walls. Magnesium is the working ingredient in chlorophyll. Both types of lime help neutralize acidic soil, which is also a side effect of too much rain.

A compound called greensand includes a different mixture of beneficial minerals including potassium, iron, and phosphorus. It’s usually available at better garden centers.

You can even use granite dust to add a wide array of minerals to your soil. If you look closely at granite, you’ll notice it’s made up of thousands of different crystals fused together. Each crystal is essentially a different mineral, including many that plants require in tiny amounts: potassium, calcium, iron, magnesium, phosphorus, manganese, and others. These minerals become more available when ground into gravel, or even into dust, and are broken down further by organisms and naturally occurring weak acids in the soil. Ready sources of granite dust include stone yards, or gravestone monument carvers.

Spread a few handfuls of lime, greensand, or granite dust over your compost mix and work it in a bit. Water the mulch well, and cover it with two layers of burlap. The burlap works as insulation, keeping the soil and sheet mulch slightly warmer than the air, and provides the dark, moist environment soil organisms prefer. Most coffee roasters will gladly give you discarded burlap bags their raw coffee beans are shipped in.

Once or twice during the winter, pull back the burlap and turn your compost mix, covering it again with the burlap when you’re done. In the spring, you should be able to remove the burlap and either plant directly into the finished compost, or work it into your soil a bit if it’s not completely done.

Copyright © 2006 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.