How To Improve Garden Soil in Winter

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Use these tips to improve your garden soil in winter to make sure it's ready to go (and grow!) in spring.

Many gorgeous, low-maintenance gardens flourishing in spring owe plenty to the soil preparations done the previous winter. Here’s how to improve garden soil in winter. These tips will help you make the most of this less lush yet still important time of year.

Grow Cover Crops

Winter cover crops are plants grown to protect the soil from erosion and nutrient-leaching caused by the cold, harsh elements. These plants also prevent weed infestation and “fix” nitrogen that’s been depleted during the growing season. Cover crops also provide green manure that can be worked in to enrich the soil in spring

Starting a cover crop is easy. The process is the same regardless of location or climate.

  • Sow a cover crop between 15 and 45 days before your first frost, taking care not to plant too early.
  • Scratch the surface of the ground with a rake and spread your chosen seeds over the entire area you want to protect.
  • Drop the seeds liberally so the crop comes in nice and dense, as if seeding for grass — about two to five pounds for every 1,000 square feet.
  • Depending on the size of the area you’re covering, seeds can be scattered by hand, with a hand-powered spreader, a shoulder spreader or a walk-behind push spreader.
  • Lightly rake again to set the seed in place, then cover with one inch of straw, hay or other organic mulch.
  • Cover crops are durable and almost drought-resistant, so there’s no need to water unless the soil is really dry.

To add nitrogen, choose a legume cover crop like red clover, crimson clover, vetch, peas or beans. To address erosion, weeds or too much nitrogen, choose a non-legume nutrient scavenger like rye, wheat, barley, oat, annual rye, mustard, brassica or radish.

A cover crop seed mix is a popular option because it addresses the range of common problems and can be used in all regions. This no-till cover crop seed mix includes clover, fenugreek, vetch, flax and buckwheat.

Be aware that cover crops are winter-hardy or winter-kill. Winter-hardy crops live through winter and add more growth in spring. Winter-kill crops are killed by frost and left to decompose on the surface until spring. This breakdown of the various options and benefits by Lisa Kubik, field manager for the Soil Health Partnership, is a helpful resource.

Cover With Mulch

If you don’t want to plant cover crops, cover your garden soil with mulch, which protects the ground from the winter elements while holding everything in place.

Organic mulch is the way to go. Bark, wood chips, straw, grass clippings, rice and other seed hulls are great options. In addition to providing protection, they put nutrients back into the soil as they biodegrade, ultimately creating more organic materials for the microbes to feed on.

Fallen winter leaves naturally occurring on your property also make perfect mulch. Allow the leaves to dry out, go over with a lawnmower to shred and spread at a depth of two to four inches. While they can be left whole, shredding leaves with the mower helps them break down and work into the soil much faster.

Decomposed granite (DG), pea gravel and rip rap (decorative rocks or coarse stones; same concept as river rock but more squared-off in shape with jagged edges) are all examples of inorganic mulch. If that’s all you can get, use it. The main goal is to leave no bare, exposed ground.

Compost

This is easily the best item on this list for improving garden soil in winter. If you’re already composting, well done. Just remember that the colder temperatures slow decomposition, so chopping your “browns” and “greens” into smaller bits will help them break down faster.

If you’re not, start composting ASAP. Here’s why: Good soil is alive and teeming with microorganisms that establish complex symbiotic relationships with the root systems of everything you plant. They become key to each other’s ability to thrive. These microorganisms need to eat, and there’s no better food to feed them than compost.

It’s much easier than you might think! You can easily start with supplies you already have. It may seem counterintuitive, but winter is a good time to start composting because things happen at a slower pace, and the routine can be eased into without feeling overwhelming.

Consider Converting To No-Till or No-Dig Gardening

Winter is a great time to consider no-till or no-dig gardening, two similar (but different) ways to improve garden soil.

No-dig gardening, usually done in raised-bed gardens, doesn’t cut into or turn the earth in any way. Amendments are layered within raised planter beds to create the growing mediums and then left undisturbed.

Using raised beds ensures there’s no foot traffic compacting the soil. This means earthworms and other organisms can keep things sufficiently aerated, as nature intended. As long as the areas are small enough to do the same, the practice can be done directly on the ground.

No-till gardening is almost the same thing, but allows for some light, less-invasive methods of getting below the surface of the earth, as long as it’s not actual rototilling. Rototillers rip and tear into the earth, breaking it apart into loose crumbles.

The theory behind it isn’t bad. It just doesn’t account for the intricately webbed ecosystem of microorganisms so essential to optimal plant health, because rototilling destroys that ecosystem.

Maria Webster
Maria is an award-winning landscaper turned expert horticultural writer, from the desert southwest. In addition to contributing to multiple home and garden outlets, she enjoys writing about mental health and personal growth & development. Writing is a favorite hobby, and she regularly publishes personal essays and elegiac poetry on Medium, where she's been curated in multiple niches. Her other passions include horses and cooking. Maria attended college in Texas and earned a bachelor's degree in education. She's currently based in Arizona with her 80-pound Red Heeler/German Shepherd, Dodger.