cover crops
sow a cover crop
grow plants whose job is the soil itself — living cover that feeds, protects, and rebuilds between harvests.
a cover crop, or green manure, is a crop you grow for the ground rather than the plate. it keeps the soil covered and rooted through the gaps in the year, fixes nitrogen, mines minerals from deep down, feeds the microbiome, and smothers weeds — then it is cut down and returned to the soil it built. it is one of the fastest ways to lift a tired bed.
the method
- 01
choose the crop for the job
legumes like clover, vetch, and field beans fix nitrogen from the air. grasses and grains like rye build fibrous root mass and organic matter. deep taproots like daikon and lupin break compaction. brassicas like mustard grow fast and smother. mixes do several jobs at once.
- 02
match it to the season
sow a hardy overwintering mix (rye, vetch, field beans) in autumn to hold soil through winter, or a fast summer mix (phacelia, buckwheat, mustard) into a bed that is between crops for six weeks or more.
- 03
sow dense
broadcast the seed thickly over a raked surface, rake it in lightly, and water. you want a solid stand that outcompetes weeds, not a thin scatter that lets them through.
- 04
terminate before it seeds
cut, crimp, or pull the crop while it is flowering but before it sets seed — that is when its biomass and nitrogen peak, and it stops the cover from becoming next year's weed.
- 05
return it to the soil
leave the cuttings on the surface as a chop-and-drop mulch, or lay them under a no-dig compost layer. let the roots rot in place — that channel of decaying root is a gift to soil structure and fungi.
field notes
- leave at least two or three weeks between terminating a leafy green manure and sowing the next crop, so the flush of decomposition settles.
- phacelia and buckwheat flower fast and pull in hoverflies and bees — a cover crop that doubles as an insectary strip.
- even a six-week gap in a bed is worth covering. bare soil is always the more expensive option.
common mistakes
- ×letting a cover crop set seed, so the fix becomes a weed problem you sowed yourself.
- ×digging the crop in and sowing straight away — the rapid breakdown can rob young seedlings of nitrogen for a few weeks.
- ×sowing too thin, so weeds fill the gaps you meant the cover to hold.
plants for this practice