Friday, July 18, 2008

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.

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