It’s weird to think that now that our gardens have just started taking off and we need to start thinking about prepping them for winter. But this is the place that we live in. We enjoy the summer months and the warmth that they bring, but we all understand that winter is always looking over our shoulder, lingering in the backdrop - we need to start thinking about getting our gardens ready for it. Luckily the cold weather is still far enough away that we are not needing to cover up our gardens with frost cloth yet. But there is one thing that we should get a start on now that will help out our gardens for next season. Planting cover crops. Cover crops are crops that are planted not for a harvest, but to cover the soil. Cover crops have been a common practice in agriculture for almost as long as humans have been farming. They are beneficial for a variety of reasons including
Soil erosion
The bio mass of the roots helps to hold together the top soil, preventing the loss of valuable nutrients from top soil erosion.
Water conservation
The biomass helps to retain moister in the soil by preventing runoff and evaporation. The extra biomass above ground also adds to the evapotranspiration of your garden creating a micro climate that is cooler reducing water loss through evaporation.
Pest management
The cover crops help to create a more diverse food source for pests. Instead of the pests only being able to eat the plants you are growing for harvest, they can munch on the cover crop that are adding diversity to your garden. In addition to this, the cover crops create an environment for natural predators to live in.
Weed management
The biomass will out-compete many weeds in our gardens preventing the spread of noxious weeds.
Soil health
In addition to all of this, cover crops are great for restoring soil nutrients. Many plants that are used as cover crops have properties that restore nutrients into the soil, such as legumes for their rhizobia bacteria in the roots, or clovers for their tap roots that pull up deeper nutrients.
There is a large variety of cover crops out there, from clover to barley to radishes. What kind of cover crop you should use depends heavily on what you are wanting to get out of your soil, as well as what region you are gardening in. Luckily for us, the Gunnison Conservation District has done all of this work for us already. They have created a cover crop mix specialized for the Gunnison Valley. I caught up with Sam Liebl with the Gunnison Conservation District, and fellow victory gardener, to learn more about this cover crop. He broke it down for me and explained why this cover crop mix is best suited for the Gunnison Valley. Here is what he had to say about it.
“Our short growing seasons in the Gunnison Valley can make the prospect of cover cropping seem daunting. Fortunately, frost tolerant species like those included in this mix allow us to improve soil with living matter either very early or very late in the year. Let's look at each species in the mix and see why it earns its place in our garden beds.”
Oats
At the Gunnison Conservation District, we sometimes assist landowners by searching the country for the seeds of rare and therefore expensive species. Oats is not one of those species! Indeed, oats is one of the least expensive options we have for cover crops because it's grown in vast quantities across North America. Oats is a dependable and versatile cover crop that enjoys cool weather. It creates an abundance of above- and below-ground growth that suppresses weeds while soaking up excess nutrients, such as the nitrogen we add to our soils with manures. Oats helps legumes such as hairy vetch and red clover grow and can help those pea family plants contribute more usable nitrogen to soils. Winter will kill oats, and spring crops can often be planted directly into the brittle oats residue.
Triticale
Triticale is a cross between wheat and rye that, like oats, produces lots of carbon-rich biomass. Triticale can soak up excess nutrients in the soil and then slowly release them as the plant material breaks down. This grass provides good erosion control and works as a natural trellis with climbing legumes like hairy vetch. Because triticale is grown on a large scale as a cereal grain, it’s a very affordable component of a cover crop mix.
Hairy vetch
This legume species can replace nitrogen fertilizers in a garden. Vetch fixes nitrogen from the air into readily available mineralized nitrogen. Its vigorous growth helps to smother weeds, and its roots condition soil so that it can soak up and hold more moisture from snowmelt and rain. Unlike oats and triticale, vetch has a high nitrogen to carbon ratio, so it breaks down quickly and completely in soil once it has been terminated by cold temperatures, mulching, or tilling. Vetch will climb up stalks of oats and triticale while its nitrogen production enhances the growth of those grass species. The USDA rates vetch as hardy to Zone 3 (much of the Gunnison Valley is classified as Zones 3 and 4), so some plants may survive the winter especially if they are sheltered by snow.
Red clover
Many legumes produce more nitrogen and biomass than red clover, but no other pea family cover crop species is adapted to as many climates and soil types. This species is dependable and low cost. It grows as a biennial, short lived perennial or annual depending on the species variety and the extent to which it’s sheltered during winter. Red clover compliments oats and triticale, and red clover produces more usable nitrogen in soil when planted with those grass species. The taproot can penetrate soil several feet deep, so red clover works as a great soil conditioner. Red clover has been used as a cover crop in North America since European farmers arrived with it in the 1500’s.
There are many other species worth considering as cover crops in the Gunnison Valley. Annual rye, buckwheat and common flax are just a few. Farmers and gardeners across North America are waking up to the value of cover crops after nearly a century of neglecting these useful plants in favor of synthetic herbicides and fertilizers. There are now many cover crop seed suppliers to choose from and a vast body of research about how to use them most effectively. The future of food production, both large and small, looks to be covered in cover crop.