Weed and pest management on organic and transitioning farms requires a holistic approach. It relies primarily on preventing and avoiding pests with cultural and mechanical suppression. NRCS coordinates conservation plans with farmers’ Integrated Pest Management plans to protect natural resources and benefit the ecosystem.
For example, organic farmers can plant insectaries to attract beneficial insects, like ladybugs, that biologically control pests. They can use companion planting within or bordering rows to draw pests away from crops. Installing nesting sites such as bat and owl boxes can also help manage pests. Livestock can be used to graze weeds. Cover crops naturally break the cycle of soil-borne diseases, and some soil-dwelling insects, while increasing the soil’s organic matter.
One of the greatest challenges organic farmers face is weed management. A single weed can produce more than 10 million seeds, and if they’re not dealt with in time, they can present farmers with challenges for years to come. Instead of using chemical herbicides, organic farmers can work with NRCS to implement a variety of innovative practices that suppress weeds while continuing to build soil health.
“We farm organically by dealing insects and weed problems using non-synthetic measures. We also deal with intercropping and crop rotations. It’s a big misconception that it’s more difficult to farm organically than it is to farm using conventional methods.”
– Gene Thornton, Sneaky Crow Farm, Roanoke, AL
Cover crops are one of the most effective tools for suppressing weeds, and they work in three ways.: When alive, they outcompete weeds for water, nutrients, and sunlight. As mulch, they minimize weed growth by physically preventing the germination of weed seeds, cutting off access to light and warmer temperatures.
When certain legumes, cereals or brassica decompose, they produce natural herbicides that can suppress weed seed while sequestering carbon. Crop rotation, timing planting dates to escape weed germination windows or increasing seeding density to suppress late-germinating weeds are other strategies.
NRCS can also help growers implement conservation tillage practices. Organic no-till uses tools like the roller crimper, which rolls cover crops in one direction. The rolled cover crop acts as mulch, preventing annual weeds from growing through.
To reduce weed pressure, farmers can also use a variety of mulches. Made of natural materials, paper or plastic, mulches are installed at the beginning of the growing season and trap soil moisture while preventing sunlight and weed growth. Plants grow by using photosynthesis to convert sunlight into energy. This process requires specific light wavelengths, which differ from crop to crop. By reflecting light from the appropriately colored plastic mulch onto plant leaves, plant development can be greatly accelerated. Examples include red plastic mulch for tomatoes and metallized silver for peppers and potatoes.
“Weeds are the most expensive thing on this farm. The fewer weeds we have, the more profitable we are.
“If you need to grow a profitable crop and get rid of bindweed, the plastic is huge. And it saves us a bunch of water by trapping water that doesn’t evaporate through the surface.”
Red Wagon Organic Farm
Any non-synthetic material, such as wood chips, leaves, or straw, or any allowed synthetic material such as newspaper or plastic that serves to suppress weed growth, moderate soil temperature, or conserve soil moisture*. NRCS can help producers with a variety of mulches, including plastic mulch, green mulch and paper mulch. [* per the USDA’s National Organic Program (NOP)]
Weeds are found in even the best-managed organic vegetable fields, but the organic farmer has many options to reduce these problems without using synthetic herbicides. These include intercropping or even reduced row spacing, adjustments to seeding rates and dates, fertilizer schedules that help crops outcompete weeds, plastic mulches, and cultivation tools for specific soil conditions.
“I am hilling with discs and sweeps; metal discs throw soil on the vegetables, smothering the weeds but allowing the leeks to keep growing.”
Full Plate Farm
1949 Allis-Chalmers Model “G” tractor with attachments used to efficiently weed and better cultivate crops.
Organic farmers can use a variety of mechanical tools, including tractor-mounted cultivators to efficiently weed and better cultivate crops, though tillage can also reduce soil organic matter and even lead to erosion.
Creating pile of soil at base of plant or bed (usually with a tractor attachment)
“V” shaped blades attached to shank of tractor that slice, drag or bury weeds
Each spring (and throughout the season) workers at Minnesota’s Blue Fruit Farm wrestle with weeds that compete with their fruit crops for vital nutrients. While hand weeding is difficult, costly, and time consuming, making bones creak and bodies ache, it can also be intimate, effective, and rewarding. And for Jay and Bea, hand weeding can even help keeps things in perspective and connect them more deeply to the seasons … and to the earth.
“Weeds are brilliant opportunists and have incredible ways to proliferate,” Jay points out. “We can all learn perseverance from weeds!”
“Cancer rates are higher among farmers than any other profession,” Bea adds. “We all deserve better than chemical-laden food, land and water.”
The act of removing weeds manually, without the use of machinery or applied chemicals.