Often as the growing season slows and we have been enjoying the fruits of our labor we forget to give back to the garden. We pull plants when they stop producing and leave the garden untouched until it is time for the fall yard cleanup. We rake leaves, pickup sticks and maybe till some leaves and compost into the garden to “put it to bed”. But what about that period of time between when you pulled your plants and you get to the traditional fall work? The weather has chilled, and the length of time is too short to plant anything else, so what can be done to help prepare the garden for the spring? Be proactive and increase soil fertility without promoting weed growth; Plant a Green Manure!
For years farmers have been rotating their crops and planting “Green Manures” or “Cover Crops” in their fallow fields. Green Manures are plant varieties which help to replenish nutrients to the soil that your plants have used to grow and produce throughout the season. They store or “fix” these nutrients into the soil, or themselves, and then are turned into the garden early in the spring. Use of green manures can drastically reduce or even eliminate the use of fertilizers in the spring. But that’s not it! Other positive benefits of cover crops include: weed suppression, creating a habitat for pollinators and beneficial predatory insects, keeping the soil from becoming compacted or eroding, and some varieties have extremely deep roots which tap into nutrients deep in the soil and bring them to the surface.
So what plants make the best Green Manures? The list is extensive, but below are some of the better known varieties.
The Legume Family is one of the widest used Green Manures. This consists of many different types of clover, peas, vetch, and others. They contain symbiotic bacteria in their root system which fix nitrogen in a form plants can use. Bean and Pea varieties are also legumes, and the idea of successive planting of crops needing nitrogen rich soil in the area previously inhabited by them reflects the same concept of Green Manures and how to use a plant’s natural characteristics to your benefits. Other commons not in the Legume Family include Rye, with its deep roots and hearty characteristics, great at withstanding colder temperatures and decreasing erosion, as well as buckwheat and sorghum.
Planting Green Manures is easy and though each type has some differences in how it is “harvested,” they generally follow these easy steps:
2. Let grow. Some heartier varieties will slow in colder temperatures, and then resume growth in the early spring and others will die back.
3. Come spring, mow down before it goes to seed and then till into the soil.
4. Always wait 3-6 weeks after tilling to plant your new crops. This allows time for the nutrients to be released into the soil through decomposition. Also, in the case of cover crops like Rye, the compounds which keep other seeds from germinating (one of its benefits when in use) will then no longer be present in the soil.
Now do you “Fallow”?
Green Manures/Cover Crops can be as simple or complex as you want to make them. You can mix varieties and calculate the exact amount of max nitrogen output per square foot or just scatter some clover and have a beautiful green carpet. Naturally give back to your garden and its habitat to keep it healthy and producing so you can continue to enjoy it for years to come!