Lincoln Fishman and Hilary Costa of Sawyer Farm have been farming organically at Sawyer Farm in Worthington, MA, since 2010. At 1,600 feet above sea level, their farm sits on a slope, is rocky, has poor drainage and experiences very cold winters.
Fishman applied cover crops and homemade applications of composted manure to build up the soil health. Like many farmers, he tried many solutions to reduce erosion, including contoured beds on the five acres that produce their livelihood of vegetable crops, cabbage, carrots, corn, garlic, onions and hemp. The pattern of increasingly heavy autumn rains that came on the tail end of hurricanes elsewhere pulled the soil they were improving down the slope while their fall cover crops were getting established.
By 2015, the frequency of their tilling was causing systemic damage which the cover crops and compost could not overcome. Switching from tilling toward tillage reduction was challenging but not as challenging as what to use instead. They tried tarps, transferred mulch, winter-killed cocktails and crimped rye with limited success.
Enter Dutch white clover, a living mulch. Like the purple heather that covers the hills in Scotland, Dutch white clover could retain the soil and moisture to keep the soil from drying out (and subsequently washing away). Commonly seen growing in lawns, it rarely reaches over eight inches. Some farmers are already familiar with under-sowing red clover under corn crops.
Spreading quickly horizontally, Dutch white effectively suppresses weeds by shading them out, yet it’s low-growing enough to minimize competition with crops and still remain manageable. Fishman’s trials have proven it to be a hardy winter perennial with decent persistence.
They tilled in spring and established their cash crops. After the last cultivation or once weeds were somewhat controlled, in July they broadcast Dutch white clover into the standing crops. By late August the clover provided 100% soil cover and thus protected the soil from heavy rains. Its benefits were that it overwintered, was easy to plow or disc down in spring, required the purchase of no new equipment, offered soil health benefits and did not appear to interfere with the growing of their cash crops. He noted that, yes, it doesn’t give as much biomass as other cover crops, but it’s on the ground, the roots are in the ground and it’s photosynthesizing.
They wondered if they could grow vegetables directly into the clover, rather than plowing it down in spring. They didn’t find any other growers trying this system, but their research discovered that some university studies were being conducted along the same vein with varying results. They tried it and found it worked – depending on the crop.
Their work is considered an adaptation to both address and withstand climate change. Fishman does not recommend using other varieties of clover for this system. At first they planted directly into the clover using a bulb auger on a cordless drill. Now they mow the clover, then plant their seedlings using a modified transplanter.
Striving toward a reduced-till system supports Fishman’s vision for Sawyer Farm to manage a healthy, diverse ecosystem that produces food with as little labor and as few inputs as possible, reducing on-farm emissions while sinking carbon into the soil. They’ve observed one planting of Dutch white clover lasts three to four years.
At Sawyer Farm they found planting cabbage inside an acre of the clover yielded 30,000 pounds of cabbage, similar to their results of planting in bare soil. Hemp, Delicata squash and green beans had similar results to planting in bare soil. Fishman was shocked to find that direct-seeding dry beans did better than direct-seeding on bare soil. Kale and Swiss chard did well, but did not grow as large. Hot peppers were so-so. They had no luck planting sweet peppers or cucumbers inside Dutch white clover.
Pest-wise, they found no flea beetles and less of every single pest except for slugs. Slugs damaged their experimental lettuce, leaving none to sell. Field corn should work with this method, but a pair of nesting sandhill cranes pulled his corn up. On the other hand, Fishman said, “The success of growing hemp inside clover gave me the justification to utilize this process because it did so well.”
He hypothesized that the reason planting inside the Dutch white clover mulch works with the crops that it does support is because its root system is concentrated at the top six inches of soil, while the other slow-growing cash crops’ roots go deeper than that to access their nutrients. When he’s applied nitrogen to transplants that yellowed, the clover absorbed it first, but the transplants did bounce back.
Planning includes establishing the clover, seeding or transplanting your cash crop and managing the clover and weeds. You must allocate two years in your planning – planting the Dutch white clover the first year to get it established, then planting into it the second year. Fishman undersows clover with rye and oats in July so the clover has a six- to eight-week start before the first frost. He broadcasts 1 lb./acre of Dutch white clover per 1,000 square feet, or 45 lbs./acre of seed mixed 1-to-1 with yellow cracked corn or chicken feed to make the broadcast pattern of the tiny clover seeds wearing a Solo chest spreader. He makes sure to get them under the cash crop canopy.
Post-pandemic, seed costs have rocketed anywhere to $300 to $400 per 50-lb. bag. Since one planting averages three to four years, costs are offset by the reduction of prior costs of tractor passes, tilling and labor.
In the past, Fishman judged his success by how clean his fields were and has found it hard to let go of that. Now he looks for a sea of Dutch white clover. He alerts farmers to expect transplants to look yellow at first, to be slow-growing and try not to freak out or intercede apart from occasionally mowing.
On July 20, visitors attended CISA’s Sawyer Farm Reduced-Till Perennial Clover Trials workshop to examine their results. The workshop was co-sponsored through CISA and UMass Extension, involving the research underway with UMass as part of a SARE Partnership grant. The group examined trial fields at Four Corners Farm in Worthington where Fishman has his SARE test fields. The clover was lush after mid-July’s deluge of 15 inches of rain. Exposed soil in the bare soil tract was compacted at the top.
Sawyer Farm’s trials are supported in part by a CISA adaptation grant. Farmers in CISA’s catchment area can apply for an adaptation grant by contacting CISA’s Stephen Taranto at firstname.lastname@example.org.
Fishman and Will Trienens, CEO and co-founder of Cannaflower, formed a nonprofit called Momentum Ag, which funds Dutch white clover trials at farms all over the Northeast. They are currently accepting applications for 2024 trials. Email email@example.com for more information.
by Laura Rodley