Garden Fertility

We grow our vegetables organically. This means no pesticides, herbicides or chemical fertilizers. In order to keep the garden fertile we must replace the nitrogen and other nutrients that the garden plants take up and that are lost because the soil is exposed.

We are lucky to live in a rural area where there is an abundance of organic material available to use as fertilizer. The many horse farms near here accumulate an astonishing amount of stable cleanings over the course of the year. This is available free or for barter. Well-composted horse bedding can be applied directly to the soil and tilled in. The dark patch on the garden is an area covered by aged manure, ready to be tilled.

Aged manure

It may not look like it, but the manure pile in this photo represents around 10 tons of horse bedding and dung. We will apply between 15 and 20 tons to this 1/3 acre garden in the course of a year. This mass will reduce by half during composting.

Fresher material can be composted beside the garden before application or can be applied on top of the garden as a mulch after plants are up. We apply it between potato rows, for example, where it keeps the weeds down, holds moisture and ultimately will be tilled in once the potatoes are harvested.

Composted manure

On the left is darker, more composted manure. The manure on the right is much fresher and must age for a while before being applied. Sawdust in fresh horse bedding can actually rob your soil of nitrogen if it is applied before it is allowed to decompose.

We also make use of green manures: we plant annual rye (and sometimes legumes) on the garden in the Fall. This grows a bit before hard freeze, then is mostly dormant in the coldest part of the Winter, resuming growth only on warm days. By mid-March, it has formed a thick, rich carpet above ground and has sent a tremendous amount of roots deep below the surface, slowing erosion and preventing cold-hardy weeds from getting an early start. On top of their benefit as nitrogen-fixers, the cover crops add organic material to the soil when tilled under. This we do at least twice before we can plant, so we only cover-crop parts of the garden which will receive mid-season plants like tomatoes and squash. Early season crops like lettuce and potatoes are planted where we fertilize with horse manure.

Winter rye

Winter rye, enjoying some sun and rain mid-February. It will survive snow and ice.

Our garden has been producing abundant food, most of which we’ve sold at farmers’ markets, for 27 years. Fertilizing it with organic matter like horse bedding and rye requires more effort and time than using fertilizer out of a bag, but produces a better garden soil and, we think, healthier crops.

Make sure you know what you are putting on your garden! More information on composting manure is available here: http://whatcom.wsu.edu/ag/compost/horsecompost.htm