I’m getting calls from people who’ve been growing vegetables in their kitchen gardens for several years but nothing much is growing anymore. Simple answer: they have depleted the soil’s nutrients by growing and not replenishing it. They’re calling me because they assume I have some magical, green thumb that can grow even in their sick soil. No luck.
Healthy soil is the key ingredient to a successful garden. (See my earlier rant.) Without it, your garden simply can’t thrive and be bountiful. Healthy soil provides your plants the nutrients they need to grow and to resist disease and pests. Healthy soil is much like your body: take good care of it and it’s productive and works well for you; don’t take good care of your body and it gets sick.
Soil gets diseases too. Recently, I visited two sad, depleted gardens. Both had serious fungus problems. In one, the soil was so depleted that nothing, not even weeds were growing. The owner complained about her last three tomato crops turning black and shriveling. She had depleted her soil to the point that it was contaminated with tomato blight, a fungus that also afflicts potatoes. Her only organic remedy, I think, was to sod her bed and find a new garden location as far away from the contaminated soil as possible. The other depleted garden smelled like my grandmother’s musty attic, had no organic matter, and only three stubby earthworms and no spiders, indications of poor soil for growing.
If your soil is depleted or you’ve grown in the same spot for two consecutive years, there are many things you can do to restore it and return organic matter for growing. Here are a few:
- leaf mulch it
- compost it
- fertilize with fish emulsion fertilizer
- add 1.5 feet of vegetable garden soil mix (See also Get Dirty.)
- all of the above
One year, I sowed a manure cover crop of legumes, vetch, rye and other plants to give back to my garden in gratitude for the bounty I’d enjoyed for several years. Any children’s library book about George Washington Carver will tell you what to do to restore your soil’s richness. Crop rotation can help too. Brassicas, members of the cabbage family, use a lot of nitrogen from the soil. So next year, plant legumes — peas or beans — in the former cabbage patch. Legumes put nitrogen back into the soil through the bacteria that live in the root nodules. When the legumes are done producing, cut the plant off at the ground to leave the nitrogen-producing root nodules in the ground and to keep enriching the soil.