CORVALLIS, Ore. — While no-till isn’t new, most research has focused on field crops. Home gardeners are catching on.
“The concept of no-till has been around for a couple of decades, but research has been very focused on field crops like wheat and corn,” said Erica Chernoh, horticulturist with the Oregon State University Extension Service. “There’s not much on vegetable production or fruit. There’s a lot to learn, and research is ongoing.”
Tilling compacts soil, destroys air-and-water pores and can increase runoff, erosion and surface crusting. It also disrupts microorganisms and other soil life that cluster around roots and drive soil health.
As microbes feed on organic matter (and on each other), they release plant nutrients and produce substances that bind soil particles into larger aggregates that keep pores open. Fungal hyphae help hold aggregates together; earthworms and other organisms create additional pore space.
Another benefit: tilling brings buried weed seeds to the surface where they germinate. Keeping soil protected with mulch suppresses weeds and leaves dormant seeds buried.
No-till has tradeoffs. Thick mulch can make direct seeding harder without specialized tools, and covered beds may warm more slowly in spring.
“Mechanical tillage does have its place, especially for establishing new beds with high compaction and low organic matter,” Chernoh said. “In most cases, though, non-mechanical approaches can help you meet your goals without the negative effects of tilling.”
Mulch and cover crops
Cover the soil year-round. Home gardeners can use straw, compost, aged livestock manure, dried leaves or grass clippings as mulch. Pull mulch back in early spring to let the sun warm the soil.
Cover crops are useful but can be tricky to terminate without tillage. If you plant a winter cover, seed in early fall. In spring, mow after flowering but before seed set, then transplant or direct seed into the fine mulch they leave.
Choose species that winter-kill or can be managed by mowing rather than tillage or herbicides. Good options include Austrian winter peas, crimson clover and fava beans.
At summer cleanup, cut tops and leave roots in place. Less disturbance means more food for soil organisms as roots decompose. Use clippings as mulch.
Create a lasagna bed (sheet mulching)
Start in fall so layers have winter to break down.
Mow grass as low as possible, or start on an old planting bed.
Loosen the soil with a digging fork to improve aeration. Even punching holes works.
Remove weeds.
Build a simple raised frame or mound layers into an unframed bed.
Lay overlapping cardboard as a base and water it.
Add alternating 2-inch “green” layers (fresh plant debris, grass clippings, fresh animal manure, food scraps) and “brown” layers (dry leaves, wood chips, straw, shredded newspaper) until the bed is about 18 inches deep.
Top with a 2- to 6-inch brown layer; use the thicker end if planting right away.
Keep beds only as wide as you can reach from the sides, and make paths (mulched with straw) to prevent compaction.
Expect beds to settle as materials decompose and refresh layers as needed.
For details on sheet mulching consult Sheet mulching and lasagna composting with cardboard.
Transplanting and direct seeding
Transplants are often easier in no-till systems. Use a trowel to open holes through the mulch and plant directly.
For direct seeding, pull mulch back and smooth the surface with a rake. After seeds emerge and seedlings establish, re-apply a thin mulch to protect soil and suppress weeds.
Previously titled No-till gardening keeps soil – and plants – healthy
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