Kayla planted this garden with hairy vetch on New Year’s Day. It took her about ten minutes to plant this space with a nice cover crop. Her ten minutes of planting will reap a lot of rewards in this garden.
Hairy vetch is a cover crop. Cover crops are designed to:
- improve soil fertility through nitrogen fixation (also called “green manure”)
- provide a “living mulch” to other plants;
- control weeds;
- provide nutritious, protein-rich animal fodder;
- attract beneficial predators; and
- increase the bio-diversity of the soil.
In Rockport, hairy vetch is best planted between November and February. Vetch is winter hardy, and a freeze will not kill it. Up north, they plant vetch in August or September, before the first killing frost, and the vetch winters under a thick blanket of snow, and resumes growing in the spring when the snow is gone.
It takes about 90 days for vetch to fully mature, and create beautiful purple blooms. When the vetch is ready, you can cut it down for a garden full of thick mulch, and then plant vegetables in it. By using vetch, no herbicides, soil preparation, or mulching is needed to plant vegetables. Or, the vetch can be plowed under. Or, animals (chickens and pigs especially) can be grazed on the vetch, to eat it to the ground. Grazing animals on a vetch patch is one of the best things a gardener can do to improve soil health.
Additionally, other plants can be combined with vetch. Vetch can be used as a companion planting with tomatoes or a Three Sisters garden. Gardeners often mix winter rye with vetch, as a premium cover crop that also makes excellent animal fodder.
Vetch takes nitrogen from the atmosphere, carries it down to the plant’s roots, and “fixes” it to bacteria in the soil. The nitrogen is then available to the next crop planted in that soil. This is called the “green manure” effect. I slept through every science class from 1st grade through college, but this dynamic fascinates me. Vetch adds between 90 and 200 pounds of nitrogen per acre. That is an enormous amount of fertilizer created simply by growing a plant.
Modern large-scale farms use “chemical nitrogen fixation”, also called “industrial nitrogen fixation”, to add nitrogen. In other words, they use synthetic chemicals to fix nitrogen. This is how big corporate farms (and many small-scale farmers and backyard gardeners) fertilize their crops.
Before these chemicals were invented–basically all of human history prior to World War II–farmers used “biological nitrogen fixation”, or cover crops, to fix nitrogen into the soil.
Thomas Jefferson, in his Farm Book and letters, writes extensively about the benefits of cover crops. In a letter to George Washington, dated June 19, 1796, Jefferson writes, “…but true winter vetch is what we want extremely…” Jefferson routinely rotated vetch or clover in his gardens, plowing them under in the spring, or grazing animals on the mature crop.
Before chemicals, all farmers used cover crops and manure. Today, it is rare to find a farm that uses cover crops and manure to grow vegetables.
Other Benefits of Vetch
In addition to its benefits as green manure, vetch also prevents weeds by choking them out and serving as a living mulch. Because vetch is about 20% protein, which is extremely protein-rich for a plant, it makes excellent animal fodder. Vetch also makes a good home for beneficial predators, and keeps them patrolling the garden between vegetable plantings. Bees love the purple blooms.
How to Plant
Vetch can be hand broadcast, which simply means to throw it across the garden. Start in one corner and work your way across, evenly spreading the seeds. You can cover a full acre with about 25 to 35 pounds of vetch seeds. If you are planting a smaller area, estimate the pounds of seeds you will need for that space. Place the seeds you will plant in a pot or bag, and carry that with you as you plant the garden. You can use the declining volume of seeds in your pot to determine how much to cast, and thus make sure you achieve an even and adequate covering. Save the remaining seeds in a cool place until the next planting.
The seeds require good seed-to-soil contact to ensure germination and root development. Notice the seed in this picture sends a shoot up, and a root into the soil. You should till up your garden space prior to planting, rather than broadcasting seeds into a field full of weeds or grass. Water the vetch planting once or twice per week after broadcasting, until the plants are established. Hairy vetch is drought tolerant, but needs some moisture to get started.
A Cover Crop View
We had just moved chickens off of this 2,000 square foot garden, before Kayla went out to plant it with vetch. The chickens had eaten down all the remnants of corn, beans, squash, cucumbers, melons, herbs, and wildflowers, to leave a completely bare space. Then we quickly formed the rows you see behind Kayla. We will plant Three Sisters in these rows once the vetch grows thick.
We will give an update on this garden, and post pictures, to show how the vetch develops, and to see what kind of return we get from Kayla’s ten minutes of planting on New Year’s Day.