Reflections on Cover Crops and the Vital Role They Play in Organic Farming

By April Thatcher, farmer at April Joy Farm and OFRF Board President

Cover Crop Seed at AJF | Oats, radish, vetch, barley, and red clover.

Cover crops are a central part of balance on my Southwest Washington farm. In fact, they’re a vital tool in organic systems across the United States, helping to regenerate the soil, suppress weeds, and build resilience in the face of a changing climate. And yet, I’ll admit, for all their benefits, cover crops have been a source of some head-scratching moments for me over the years.

When I first started using cover crops, I had a lot of questions—many of the same ones I still hear from other new growers today.

• What mix of plants will work best with my soil type, climate, and crop needs? 
• How do I know my cover crops are adding value to my system?
• What type of equipment do I need to manage cover crops successfully?
• And perhaps the most common question I get from fellow farmers is: How do I transition from a lush, green cover crop to a seedbed ready for planting without disturbing the soil too much?

Organic farming is a relationship between the land and the farmer, and I think of cover cropping as one big, ongoing conversation in this relationship. It’s a journey of experimentation, observation, learning, and refining techniques year after year. Each piece of land, each crop, and each season calls for a different approach, and what works for one farmer might not work for another. 

On my farm, I’ve spent years experimenting with different cover crop mixes and timing strategies. I currently use a mix of cover crops—grasses, legumes, and broadleafs—depending on what I observe the soil needs. Legumes like peas and clover can add nitrogen to the soil, while deep-rooted crops like daikon radishes help break up compacted layers and improve soil structure. The key for me is to support functional diversity—both above and below the ground.

The Role of Cover Crops in a Living Soil System

When we treat soil as simply a medium to grow crops, we miss out on the extraordinary potential it has to regenerate life, sequester carbon, improve the nutritional value of our food, reduce off farm inputs, and to act as a buffer against the many challenges we face today. 

Cover crops are a powerful tool to help unlock this potential. These crops are not meant to be harvested but rather are grown specifically to feed the soil. When used strategically, cover crops can help reduce soil erosion, capture and recycle nutrients, promote nitrogen fixation, increase organic matter, suppress weeds, and even manage pests—all while nurturing the living, complex web of life in our soils. 

Cover crops are a critical tool in the organic farmer’s tool box to help build resilience on the ground—not just in the soil but in our entire farm ecosystem. And that resilience is more important now than ever as climate change presents erratic new challenges to farmers across the country.

Lessons from the Field: Cover Cropping in Practice

Cover Crop Kale | Sometimes, we don’t mow or turn under our market crops after we’ve finished harvesting. We underseed cover crops directly into these fields because, like cover crops, these plants continue to provide benefits for our system. Case in point- this tree frog has it made in the shade. Photo credit: Lauren Ruhe

I’ve learned over the years that there is no one “right” way to utilize cover crops. I’ve surrendered to the reality that on highly diversified operations like mine, cover cropping is always going to be a process of experimentation, observation, and refinement. What works one year might not work exactly the same the next, and that’s okay. If we are observant and committed to keeping records of our trials, we can glean important knowledge every season of the year. The goal isn’t perfection; it’s progress.

After eighteen years of working with cover crops on my 24 acre farm, here’s a bit of what I have gleaned – what I would tell my new-farmer-self if I could:

• Start simple and make small adjustments to your basic cover crop plan year over year. When I first started utilizing cover crops I was overly enthusiastic. Every year I’d try a bunch of different, complex seed mixes to try and find the perfect one. That was a mistake. I wish I’d stuck with a simple mix of two or three species (grass/legume/broadleaf) for the first few years. If I had done so, and made small refinements year over year, (adjust seeding rates, sowing dates, etc.) it would have saved me time in the long run. Instead of changing way too many variables every year, I would have built up a steady, reliable mix customized to my system faster- one that incrementally added stacking benefits to my system year over year. 
• Pick only one (or two at most) goals. I had so many needs when I started using cover crops. I had soil compaction, low nitrogen, low organic matter levels, and erosion and leaching to worry about. But starting out, I would have been better off picking just one of these to focus on addressing through the use of cover crops instead of trying to solve all of them at once. Over time, you can build on your success. But aim for the small wins, having faith they will add up over time.
• Be mindful of your equipment and resource limits. We have hot, dry summers at my farm. So interestingly, irrigation is a big challenge for me in terms of using summer cover crop crops. Same goes for sowing fall cover crops, which I want to sow as early as I can to maximize nitrogen fixation. Even though I have the equipment to sow, cultipack and terminate them successfully, if I can’t get them to germinate without water I’m at square one. If you don’t have equipment to crimp/roll cover crops or don’t have a flail mower, make sure to be strategic about the species in your mix. Have a plan for seeding, and have a plan for terminating your cover crops that is practical for your operation.
• Nest your cover crops into your overall crop system. Your cover cropping plan has to work within the larger context of your farm plan. Part of this means being realistic about the resources (including labor) necessary to implement your cover crop strategy (see bullet point above). Part of this means being diligent about planning your cover cropping efforts as diligently as you do crops for your market. It’s all too easy in the heat of the season to bail on your cover cropping plan because some of the details aren’t quite worked out or you didn’t order seed, etc. Be intentional about making sure your cover crop system compliments versus competes with your market crop system. At my farm, tasks for cover crop soil prep, sowing, management, monitoring, and termination tasks are all included in my annual farm plan schedule. I don’t have to think about organizing or planning anything cover crop related once the season gets started; I can focus simply on implementation. 

Every farmer who wishes to utilize cover crops successfully has specific soil health needs, goals unique to their operation, and different equipment and time constraints. So while there’s no single, universally right approach to cover cropping, we can all benefit from taking a strategic approach to working with cover crops.

Summer Cover Crop Mix | A favorite combination for warm weather. Oats, Buckwheat, Poppies and Phacelia.

Bridging Experience with Research: OFRF’s New Guide to Cover Cropping

That’s why I’m so excited to share a valuable new resource for farmers: a comprehensive organic cover cropping guide developed through OFRF’s ongoing partnership with the Natural Resources Conservation Service (NRCS). This guide is designed to help farmers—whether they’re just starting out with cover crops or refining their strategies.

What makes this guide so valuable is that it’s grounded in both science and experience. It combines years of research on the benefits of cover cropping with practical, field-tested strategies from organic farmers like myself. It provides an overview of the steps for selecting cover crops, managing them through the growing season, and terminating them in a way that benefits both the soil and the farmer’s bottom line. And it offers a collection of other regionally specific resources for farmers to dive in deeper. You can also find more in depth information in OFRF’s Soil Health and Organic Farming guide to Cover Crop Selection and Management.

Whether you’re looking to improve your soil’s health, reduce off-farm inputs, support pollinators, or make your farm more resilient to climate change, cover crops can be a powerful tool in your toolkit. This guide is full of practical, research-based advice to help farmers make informed decisions about how to integrate cover crops into their systems.

The Story of Diane Green and Greentree Naturals

Written by Elizabeth Tobey

Diane Green is a farmer, researcher, and educator, who has been tending the land at Greentree Naturals Farm in northern Idaho for over 30 years.

Nestled between the Cabinet and Selkirk Mountain ranges outside of Northern Idaho, just 60 miles south of the Canadian border, lies Greentree Naturals Farm. Diane Green and her husband, Thom Sadoski, have been tending this certified organic farm for over three decades. At its peak, this small farm had 2.5 acres in production. In recent years, as Diane and Thom have entered their 70s, they’ve downsized and are now actively farming one acre. They produce 130 varieties of certified organic vegetables, herbs, gourmet garlic, flowers, hops, and seeds—many of which are open-pollinated and saved annually. Their mission has always been clear: to build community through education, to model exemplary land stewardship, and to provide fresh, nutritious organic produce to their local community.

Over the years, Greentree Naturals has hosted numerous research projects in collaboration with local universities in Washington, Idaho, and Montana, and the Organic Seed Alliance. They’ve also received funding from OFRF and several of the major USDA research grant programs, including NIFA’s Organic Transition Program (ORG) and the Sustainable Agriculture Research and Education (SARE)—both programs OFRF works to bolster and protect through our advocacy work.

We spoke with Diane in the spring of 2024 about her experience as a farmer and the importance of research, collaboration, and community education.

Why Organic?

For Greentree Naturals, organic farming is more than a method—it’s a commitment to conservation and land stewardship. Reflecting on the broader impacts of climate change and environmental degradation, she emphasizes that everyone can contribute, regardless of their scale of operation. 

“When I look at all the things happening with climate change and the desecration of the earth, it’s overwhelming,” Diane shares. “Growing organically is about making a commitment to practicing conservation and land stewardship, and it’s something that everyone can commit to, whether they have a few grow boxes or a one-acre market garden, or hundreds of acres of food production.” 

This commitment is reflected in every aspect of Greentree Naturals, from their diverse crop offerings to their sustainable farming practices and their continuous participation in organic agriculture research and education activities on their farm.

Challenges and Adaptation

Organic crops growing in the fields at Greentree Naturals.

Farming in Northern Idaho presents unique challenges, particularly with the increasingly unpredictable weather. Over the years, Diane and Thom have kept detailed notes and observed significant changes in weather patterns, including more extreme conditions, such as 90-degree days in May dropping to freezing temperatures overnight. These conditions necessitate season extension techniques and constant adaptation. “Everything I thought was normal has changed,” Diane notes. Planning for these extremes and embracing flexibility is key to success. “I tell my gardening students that as long as you plan for the hottest, coldest, wettest, driest growing season in recorded history, you’ll be ready to grow in North Idaho. But I suppose that’s probably the same for growing everywhere anymore.”

Diane underscores the importance of on-farm research in observing these changes and developing adaptive strategies. “On-farm research [is] a way to help people focus on documenting those changes, and working together through partnerships to find solutions to adapt to those challenges,” she says. 

As the growing seasons become hotter, Diane and Thom have noticed new pests showing up. “We’ve had new beneficials too,” Diane notes. “Last year, we saw praying mantises showing up, which we’ve never had before.” But the new types of pests can be alarming and present a challenge. The farm now has three types of wireworms which were not present before. “The grad student that was specializing in wireworms was thrilled about it, we’re not so much,” Diane says with a laugh. As these variables come into play, Diane highlights the importance of clear observations and documentation. “As farmers, we’re always watching,” she says, adding that participating in research can make a difference in how you see things. “It makes you focus,” she says. “I like that.” 

Conservation Practices

Greentree Naturals produces 130 varieties of certified organic vegetables, herbs, gourmet garlic, flowers, hops, and seeds.

At Greentree Naturals, healthy soil is the cornerstone of their farming philosophy. Diane emphasizes the importance of thinking about soil as a living entity. “The more we learn, the more we know we have to learn about growing healthy soil,” she says. The farm employs a variety of practices to enhance soil health, including reduced tillage and cover cropping, utilizing mustard as a main cover crop because it germinates and grows well in a variety of conditions. They also utilize worm composting and make their own compost, supplemented with OMRI-approved chicken manure-based compost when necessary.

Intimately related to soil health, water quality and biodiversity are critical to their conservation efforts. Greentree Naturals is bordered by wild lands, leading to frequent encounters with local wildlife such as black bears, grizzlies, deer, and elk. Diane incorporates these animals into the pest management workshops she teaches, discussing how to coexist collaboratively with nature.

Research and Education

Greentree Naturals has been a hub for numerous research projects and Diane’s passion for education is evident in her extensive involvement in on-farm research and community education. She contracts with the Oregon State University and the University of Idaho as a consultant, advisor, and farmer-educator. She is also one of the founders of the Cultivating Success Small Farms Education Program and a mentor with the USDA Transition to Organic Partnership Program (TOPP) with Oregon Tilth.

Thom and Diane both have backgrounds collecting field data for the USFS, and were taught early on the importance of recording accurate field information. Their fields are mapped with numbered rows and easy-to-identify locations of plots, specific crops, and field applications. And, because they are a certified organic farm, they are required to maintain clear records of everything they do in the fields. 

The farm has been a host site for a variety of research projects, including:

• Efficacy Evaluation of Biological Control Agents Against Wireworms in Organic Production
• Soil Health and Fertility Testing to Optimize Organic Carrot and Beet Production in Northern Idaho
• Biodiversity and Natural Pest Suppression
• Extension of Local Food Production in Idaho Using High Tunnel Technology
• Combining Trap Cropping with Companion Planting to Maximize Control of the Crucifer Flea Beetle in Organic Mixed Vegetable Farms
• On-Farm Variety Seed Trials for Organic Systems

Detailed information about the research projects is available on the farm’s website. 

Hosting field days is an important part of community engagement and education at Greentree Naturals farm.

Diane believes strongly in the necessity of these research collaborations. “It’s really important with agriculture research that it’s duplicated on a farm and doesn’t only happen in a controlled university site,” she asserts. “The more we cultivate partnerships between universities and on-farm research, the better.” 

Hosting field days has also become a substantial part of how Greentree Naturals promotes farmer education and networking. They’ve had to cap attendance for these events, which often sell out. 

“Field days are a wonderful opportunity to network with other farmers, community members, and researchers,” Diane says. “We’ve so enjoyed hosting those at our farm.” They’ve found that the format of a Sunday afternoon event that includes lunch works well for them and their farming community. “Farmers want to learn from farmers,” Diane states, noting that they are always sure to pair a farmer with an extension educator or researcher so that the two perspectives can be shared side-by-side. 

Engaging Farmers in Grant Funded Research

Diane believes on-farm research is a critical component of successful organic research and innovation. 

Grant-funded research has played a significant role in the farm’s ability to conduct meaningful research. Diane was quick to note that the money is not the only reason they have participated in research projects; they have donated hundreds of hours and production space to research projects. But as Diane says, it’s much more sustainable for farmers to participate in research when their contributions are honored. “It’s much easier to let go of a production area for research if you’re compensated,” she explains. She notes that too often grantees come to the farmers after a grant is already written. She strongly encourages researchers and extension staff to engage farmers in the grant-writing process from the beginning to ensure that adequate compensation that respects the farmers is written into the proposal. 

Diane encourages other farmers to engage in on-farm research and to utilize existing resources and partnerships, noting that “as farmers, we are constantly experimenting and testing our ideas.” But, she says, “it’s important to remind ourselves we don’t have to reinvent the wheel.” There are lots of resources available from sources like OFRF, SARE, and others. Diane also recommends forming partnerships with local extension educators. “Don’t try to do these things alone,” she advises.

University students assist with an on-farm research trial.

“Applied research and partnerships are crucial,” Diane continues, emphasizing the broader importance of collaboration and community in agricultural research. “As farmers, we tend to be pretty isolated, and we tend to want to put our heads down and do what we’re doing,” Diane admits. “But I think ideally one of the best things we can be doing for ourselves and for the planet is working together and building partnerships through the agricultural community.” 

By forming partnerships and engaging in applied research, farmers can achieve more significant and impactful results, benefiting both their operations and the broader agricultural community. “It’s going to take all of us working side by side,” Diane states.

Looking Forward

As Diane and her husband begin to downsize their operations, she has concern for the future of agriculture, particularly the loss of farmland to development and the challenges new farmers face. 

“There needs to be a new model for farmland succession, especially in organic farming,” she urges. Diane envisions a future where farmland is preserved for new generations of farmers, ensuring that the biodiversity and sustainability practices they have cultivated at Greentree Naturals continue to thrive, while also supporting aging farmers in their retirement.

Conclusion

Diane Green’s story is one of hope, resilience, and unwavering commitment to organic farming and community education. Through her work at Greentree Naturals, she demonstrates that sustainable farming is not only possible but essential for the health of our planet and our communities. Her message is clear: by working together, farmers, researchers, and educators can create a more sustainable and equitable agricultural system for future generations. 

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