The Dirt on Compost

by Paddy Wales

Ah, the pleasure of dark, rich, wormy, forest-sweet compost, sifted and ready to put on the garden! Already I can imagine the gratitude of my plants' roots as the rain carries this hearty nutrient-rich meal to their tips. When you pull this gardener's Black Gold from the pile in spring and remember the kitchen and garden detritus that went into it all fall and winter, you know you have harnessed one of the great natural forces.

Many gardeners on the Coast make compost either in bins or freeform heaps. With our typically thin, sandy soil and seasonal rain, the nutrients must be replenished regularly. At the outset of spring's rapid-growth period, gardeners are adding mushroom manure, leaf mould, and seaweed to their vegetable and ornamental beds. Home-made compost is perhaps the best of all the soil amendments. It helps build up the micro-organisms and makes the soil more moisture-retentive for plant health during summer drought.

Where space is limited, use a one-metre wire and wood slat box or a plastic bin. If you have more space, a pile not higher than a metre works well. To make primo compost, alternate layers of green stuff, brown stuff and soil. Green stuff includes kitchen waste (no animal products or fats) and garden clippings, diced as small as possible. Brown stuff may be dried leaves, straw, newspaper strips, or sawdust. (I bag fall leaves for later use.) The soil layer is like yeast in bread; it provides the microbes to get things happening. Put on layer after layer, like a lasagna. To add kitchen waste, make a little hole in the pile and cover it to avoid flies.

To speed up decomposition, add some air by poking the pile with a ski pole, or fork it over every couple of weeks. To speed it up even more, add urine or manure. If worms don't appear in your compost, get a bucketful of compost from a neighbour's established pile. Grass clippings should be sprinkled in very thin layers. And of course, avoid adding anything with pesticides. But even if you do nothing, the heap will eventually produce useable compost. I sift the finished product into a wheel barrow using wire-mesh, throwing back anything that hasn't finished decomposing. Then I place it around the base of all my ornamentals, near but not touching the stems. As I pot up planters, I add a generous quantity to the soil mix, and of course, I add compost to everything in the vegetable patch. You can't have too much!

Compost Troubleshooting

There are many right ways of composting. Like everything worthwhile, learning to compost may take some time to master. Here are some suggestions.

Where should the compost be located?

Compost needs some sunlight, some rain, and of course, it must be handy for you to dump the kitchen and garden waste.

My finished compost has weed seeds.

There are two ways to prevent the compost from spreading weed seeds. The simplest is to avoid putting the flowers and seedheads of weeds into the compost. But if your composting process can generate enough heat it will kill any seeds. It may take a little experimenting to perfect this heat process. You'll need a good balance of Green Stuff, Brown Stuff and soil mixed in layers no more than four inches deep. The optimum total depth is about a metre. Manure helps heat up the pile.

I don't have enough material to start a compost pile.

Start with what you’ve got, and just make a small heap. Add more as you go along. Fern fronds, last fall's leaves, wood chips, newspaper ripped into strips (one page thick only).

My kitchen compost pail is yucky.

If you're going to store vegetable and fruit waste in the kitchen, make it easy for yourself. There are attractive pails made with filters that prevent odours. Empty the pail at least once a week, preferably oftener. After dumping the pail in the compost, I rinse it out, then put a paper towel in the bottom. It makes dumping easier.

My compost pile is yucky.

Plastic compost bins work anaerobicly, that is, without oxygen. It's very hard to turn the pile with these bins, so they may be slimy or have flies. Bins made with wood slats covered with wire grid with a front door that opens make it much easier to turn the compost to add oxygen. Or you can try to fluff the pile with a pitch fork. Or use a ski pole or metal pipe to poke holes. Grass clippings or other very fine material can prevent air circulation, so premix the clippings with leaves, or add just a little at a time.

I’m worried about rats.

Native rodents live all around us whether or not there is compost. Big city rats are another matter. Where they are a problem, a closed bin is preferable to an open heap. In my open-heap compost, I avoid grains, pasta, and bread, and always bury the kitchen scraps well. Make sure the compost structure fits snugly onto a wire mesh grid. Some people place their composter onto a concrete pad so critters can't burrow under.

What should I include?

Garden clippings (the smaller the better), vegetable peelings, old fruit and veggies from the back of the fridge, coffee filters (good nests for red wiggler worms), tea bags, seaweed, watermelon rinds (the microbes with love you), rinsed crushed eggshells, straw (not hay - too many seeds).

What should I avoid?

Cedar, animal products, oil (salad dressing), grass clippings with pesticides or chemicals, roots of noxious weeds such as morning glory, seeds of unwanted weeds. Although any plant will eventually break down, twigs and sticks, thick leaves such as rhododendron, and rigid stems take a long time. I use a separate pile for these. Too much of any one thing can slow down the compost. One time I put prawn shells in with the vegetable peelings by mistake, and all night long a raccoon banged the box to try to get in. Another time I added a thick layer of seaweed to the top, and it smelled very fishy. But a compost is very forgiving.

How do I use the compost?

Your compost is ready when the inside of the heap looks like soil. The finished compost is usually in the middle or bottom of the heap. Scrape off the rough layer at the top (this will start the new heap). I use a half-inch wire mesh screen to sift the good stuff into a wheel barrow, discarding pebbles and returning uncomposted material to the heap. Spring or fall are good seasons for adding compost to the garden. For ornamentals, I put an inch or two around the base of shrubs and perennials, near but not touching the plant. In the vegetable garden, I mix the compost into soil where the roots will find it. For pots and planters, I add compost to the potting mix. For indoor plants, I make compost tea. Mix about one part compost to three parts water in a bucket and let it stand overnight.

Paddy Wales is a well known garden photographer for Canadian magazines. She is responsible for the images that appear in Journeys Through the Garden: Inspirations for Gardeners in B.C. and the Pacific Northwest, Creating a Cottage Garden in Canada, and numerous books authored by Marjorie Harris. When Paddy is not busy photographing other people's gardens, she is busy working on her own in Roberts Creek.