Broadfork™

How to

Cover your soil for winter

The last crop is out and the bed is bare. Rain and cold will work on it until spring, so get something over it before the ground freezes.

Grown in Ohio, zone 6a. Your frost dates move the calendar; the signals don't. Broadfork goes by where your garden is, not its zone: frost dates for your ZIP code in the US, or the ones you type in anywhere else.

Seven minutes to read. The steps stand on their own.

90 percentless erosion under cover crops, in field data
2 to 4 inof shredded leaves
3 inof straw, at the least

Why cover it#

Rain hits bare soil hard. The drops break up its crumbs and seal the surface, the water runs off instead of soaking in, and it takes the topsoil with it.

In field data, cover crops cut erosion by 90 percent and nutrient runoff by 50 percent or more.

Nitrogen goes too. Microbes keep turning it into nitrate, which washes down through the soil, until the soil reaches 32 °F. A cover crop's roots take it up and hold it until spring.

Mulch does part of the same job. It takes the raindrops, holds the soil in place, delays freezing and cuts down on heaving.

a bare beddrops break the crumbsand seal the surfacenitratewashes downwater runs offwith the topsoil the same bed, coveredthe cover takesthe raindropsnightcrawlers pullresidue downmicrobes crowdthe roots
The same bed, two ways. Bare, the rain carries soil and nitrate off. Covered, it stops at the cover.

The other reason is what lives in the soil. Microbes crowd the roots, 1,000 to 2,000 times thicker than in bare soil, and one count says 10,000. Earthworms eat what's left on top, and nightcrawlers pull it down their burrows. Clear the bed and you clear away their food, and their work is what makes the crumbs good soil is built from.

Cold slows them down without stopping them. Microbe numbers double with every 10 °F of warmth and activity is very low below 30 °F, though even frozen soil goes on breaking plant matter down, far more slowly. So most of the eating comes in fall, before the soil cools, and again in spring.

From the beds in OhioShredded leaves are the mulch used here most. Fall is the perfect time to feed the soil microorganisms and tuck them in for winter, and what's waiting under the leaves in spring is like a fluffy chocolate cake.

What to use#

Shredded leaves
Free, and they give back calcium, potassium and magnesium as they rot. Whole leaves blow away or mat into a wet sheet, so shred them.
Straw
Buy it seed-free, and skip hay, which brings weed seed. It blunts heavy rain and catches snow. It's slow to rot: carbon to nitrogen runs 80 to 1, against 50 to 1 for leaves.
Pine straw
The needles lock together and stay put, even on a slope, and let air and water through. They don't change soil pH unless you dig them in. They last 2 to 4 years, so some data keeps them to permanent plantings; other data says they do no harm on vegetables.
A winter-kill cover
Oats or radish, sown early. They die over most winters and leave a mat on the bed.
A hardy cover
Rye, wheat or vetch. They come through the winter alive, their roots holding nitrogen, and you end them in spring.
The crop itself
Healthy plants, chopped up and left where they grew. That's chop and drop.

Keep what's left over. Leaves store in a wire bin, or moist in loosely closed bags. Shredded, turned and watered, they'll be leaf mold in 6 to 12 months; left alone, about 2 years.

The steps#

  1. Clear what can't stay. Diseased or pest-ridden plants come off the bed first. The list is further down.
  2. Chop and drop what's healthy. Cut the plant at the soil line and leave the roots to rot in the ground. Chop the top small, since small pieces break down faster, and spread it over the bed. Most of the data would shred it and work it in instead.
  3. Sow a cover if there's time. Oats need 40 to 60 days before the first killing frost to make a thick mulch. Rye goes in last, into mid or late October. Sow a cover crop has the rest.
  4. Too late for a cover? Shred the leaves. Rake dry leaves into a loose pile and run the mower back and forth over it, or drop them in a bin with high sides and work a string trimmer through them. Keep it coarse: whole leaves blow away and fine ones block water.
  5. Lay the mulch in mid to late fall. Wait until the soil has cooled, and get it on before the soil freezes. Strawberries and garlic have their own dates.
  6. Spread it deep enough. Shredded leaves go 2 to 4 inches, and 4 settles to about 3 by spring; one source stops at 2, because they mat. Straw goes at least 3 inches, and the data runs as high as 8 because it packs down. Pine straw goes 2 to 3 inches, or 5 where it will settle.
  7. Keep it there. Water shredded leaves once they're down. On a windy spot, lay wire fencing over straw and weight it with bricks.
2468inshredded leaves2 to 4 in 2468instraw3 in at the least, up to 8 2468inpine straw2 to 3 in, or 5 where it will settle
How deep, to scale. The dashed line is the least the data gives, and the top of the layer the most.

Short season Where winter comes early, mid-October can be too late for any cover crop, so go straight to mulch. Snow is the best cover there is, and you can't count on it.

Mild winter Where winters are mild and wet, the rain is the trouble: it carries nitrate out of bare beds, so keep a cover growing, in by September or early October. Mulch also rots faster in warm, humid weather.

In Broadfork In Broadfork, Winter mulch is a kind of task: pick the bed, and it goes on your list.

In spring#

Pull the mulch back before you plant and move it back after. Worked in before it has rotted, it ties up the nitrogen your crop needs.

Straw and leaves are high in carbon, so the microbes eating them take nitrogen from the soil first. Peppers after rye with no added nitrogen came up stunted and yellow. A bed like that needs extra nitrogen early on.

Mulch holds spring soil cold and wet longer than bare ground. Let warm-season ground warm up before you cover it again: about early June for tomatoes, and the data runs as late as July for peppers.

A winter-killed cover can stay as a mulch: plant through it, rake it aside or fork it in. Check first that it's dead, because some come through a mild winter. If you fork it in, some data says wait 2 to 3 weeks to plant, and some says oats need no wait.

What comes out first#

Some plants carry next year's trouble with them. A big, hot compost pile can kill it, but most home piles don't get there, so these come off the bed.

Tomatoes and peppers
Septoria, early blight and bacterial spot winter on their debris. Take it all off the bed.
Potatoes
Dig every tuber: late blight lives on in ones that don't freeze or rot. The data splits on whether it also winters in dead vines, so take those too.
Squash, melons and cucumbers
Cucumber beetles and squash bugs winter under debris, leaf litter and mulch. Clear the vines and any old mulch when the season ends.
Corn
Corn borers winter inside the stalks. Shred them or take them off.
Cabbage family
Black rot lasts up to two years on debris, and clubroot up to 18 in the soil. Keep diseased plants out of the compost.
Beans, peas and lettuce
Healthy ones can stay. Any that showed blight, rust or lettuce drop come out.
Weeds
Anything gone to seed, and anything that spreads by the root, like bindweed and quackgrass.

If it goes wrong#

Slugs under the cover
They lay eggs under mulch and feed on rotting plants. Where they're bad, skip the chop and drop and keep mulch to 3 inches or less; 1 inch is better.
Voles under the mulch
Deep layers shelter them. Where they've been a problem, keep it to 2 to 3 inches.
A wet, matted sheet of leaves
Too thick, or not shredded. Break it up, and shred them next year.
Grain coming up through the straw
Seed left in the bale. Let it be a winter cover.
Yellow, stunted seedlings
Planted into fresh residue with too little nitrogen. Feed them, and give the bed more time next year.
Twisted, cupped leaves
Herbicide in hay, grass clippings or compost, which can stay active for years. Before using any you didn't make, grow peas or beans in a pot of it for 2 to 3 weeks.
Soil like coffee grounds
Jumping worms. They spread in mulch, compost and potted plants. Use your own leaves, and keep your mulch at home.

Every number on this page comes from a published extension source.

Sources for this guide: Ohio State University Extension, Iowa State University Extension and Outreach, University of New Hampshire Extension, NC State Extension, Oregon State University Extension, University of Illinois Extension, University of Maryland Extension, University of Minnesota Extension, University of Wisconsin-Madison Division of Extension, Clemson Cooperative Extension, Penn State Extension, SARE, Texas A&M AgriLife Extension, UMass Extension, University of Georgia Extension, University of Nebraska–Lincoln Extension, University of Vermont Extension, Virginia Cooperative Extension, Colorado State University Extension, Montana State, NDSU Extension, Rutgers NJAES Cooperative Extension, University of California, University of Connecticut, University of Florida, University of Kentucky Cooperative Extension, University of Missouri Extension, Utah State University Extension, Washington State University Extension, WVU Extension.

The documents behind this guide (88)

Updated 11/11/2026 · Checked against our sources 11/12/2026

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