In the fall, as many gardeners put their plots to rest, some sow winter cover crops to improve the soil. Hairy vetch may sound like an insult, but this pretty plant is actually a fantastic cover crop for growing during the off-season.
A good cover crop protects from erosion, aerates the soil, and replenishes nutrients. Hairy vetch is one of the best cover crops. It does all three, as well as strangling out weeds.
Grown by itself, or paired with rye, vetch is a beautiful way to boost nitrogen levels in the soil. Whenever I’m making plans to improve the soil on my homestead, I think of vetch and look forward to a field of purple blooms in the spring.
Vetch is the Ideal Cover Crop
I first heard of cover crops when my husband apprenticed at an organic farm in southern New England. There, the farmer sowed rye and hairy vetch (Vicia villosa) in his fields each fall and plowed them into the soil after the snow melted.
If you’ve never planted a cover crop before, I’ll give you a quick introduction to the practice. We plant cover crops to improve the soil during the “off-season.” Cover crops cover the soil to keep it safe from erosion in the winds, rains, and snows of winter.
They also work to improve the soil – replenishing some of the nutrients we took out of it during the growing season. You can use them as green manure.
Most cover crops are winter grains and legumes. You plant them in the fall and then plow them in right before planting in the spring. Vetch is a legume (the same family as peanuts and alfalfa).
Since vetch flowers in early spring, many gardeners chose to plow it in before the blossoms appear. Plowing before flowering keeps your vetch from getting weedy or reseeding itself in your garden bed.
But, the flowers are so pretty. They’re also great forage for bees, who appreciate early flowering plants when they emerge – hungry – after a long winter. There’s nothing wrong with waiting until after your vetch flowers to till it into the soil!
When you’re preparing the ground for a cover crop, start by clearing out last season’s debris. Pull up dead plants, rake away leaves, and turn over the soil. If you have a plow or rototiller, you can simply till up the soil.
I like to add in any soil amendments right before tilling. I’ll sprinkle on a bit of last year’s wood ash, rake over some well-composted manure, and then till the whole mess until it looks soft and loose.
When your soil is freshly tilled, broadcast your vetch seed. Do this as soon as possible after tilling to give the vetch a headstart. If you wait a day or two, then all the weeds will have a chance to sprout first and choke out your cover crop.
You’ll want about 1-2 pounds of seed for every 1,000 square feet of garden. If your garden is much smaller, think about getting about a half-pound bag of vetch for 400-500 square feet or a quarter pound of vetch for 100-300 square feet.
Broadcast the seed by scattering it semi-consistently over the garden. I like to mark off garden space in 10x 10-foot plots, scatter them, and then cover the seed. Then I move on to the next marked plot.
If you have an especially huge garden, this method may become tedious, so feel free to use a seed spreader in rows.
Once the seeds are scattered, cover them with about a half inch of soil. Water the whole bed very well – let the water soak into the soil and then come back and water again. We don’t want standing puddles, but we do want the water to have penetrated beyond the top half inch of soil.
If you’re seeding in vetch and rye together, mix the seeds before scattering to allow for a natural intermingling of your crops.
When to Plant
Since vetch likes to put out an initial growth before going dormant in the winter, it’s best to plant it about a month to 40 days before your predicted hard frost. For us in New England, that puts planting sometime around the first of September.
Of course, you can also plant vetch in early spring for a bright, summer flowering. Or in early July if you want to harvest it as animal fodder. Most people who grow vetch use it as a winter cover crop, but don’t limit yourself. Vetch is an abundantly functional plant.
If you do plant your vetch too close to a hard frost, or you end up with a suprise early freeze, don’t worry, your springtime vetch might be a little behind, but in most cases, hairy vetch planted too close to winter, will still come up in the spring.
Since hairy vetch is hardy down to -20°F, it’s able to survive even in some of the harsher winter weather we have. It works as a successful cover crop in temperatures down to USDA Hardiness Zone 3.
Hairy vetch doesn’t do well in heavy, poorly drained soil. If your soil is compacted or tends to hold water, you may want to look into other cover crops.
Ideally, vetch prefers sandy, well-drained soil with a pH between 6.0 and 7.0. But it can adjust to less-than-ideal conditions as long as its need for well-draining soil is met.
Vetch grows best in full to partially sunny spots. Especially if you’re planting before winter as a cover crop. Vetch will establish more quickly and firmly in a space that provides plenty of sunlight.
Vetch in Fall, Winter, and Spring
Once sown, your vetch will quickly germinate and start to grow. There’s no need to thin the vetch if you’re using it as a cover crop. If you’re growing it for its pretty flowers, thin your plants to about 3-inches apart.
Hairy vetch grows slowly in the fall, but growth continues throughout the winter – under the snow. In the spring, your vetch is firmly established. As the temperatures warm up, hairy vetch starts growing quickly. It rarely gets over 3 feet tall, but it’s long, trellising vines can reach over 12 feet long.
If vetch is grown with a grain like rye, it will happily trellis up the grain stalks.
Let your vetch grow until about 3 weeks before it’s time to plant summer crops in the garden. Most growers like to cut down the vetch before it flowers, to avoid letting it seed in the soil. But if you don’t mind a fresh crop of vetch starting in the fall, enjoy the flowers.
Since it’s primarily growing during the winter, vetch doesn’t have a lot of trouble with pests. You’ll rarely have trouble with diseases either. The winter weather will kill off most of the common pests and diseases before they have time to damage your crop.
But in early spring and late fall you may have trouble with a few of the common pests.
These little pests are a problem no matter what you’re growing, including vetch. If you see aphids on your hairy vetch, it’s time to pull out your trusty bottle of insecticidal soap. Spray the underside of the leaves whenever you see signs of aphid damage.
If you have a huge expanse of vetch, be sure to add in neem oil as well. Neem oil reduces the chance that your invading aphids will have baby aphids and start a community of aphids in your garden.
Slugs and Snails
Like aphids, slugs and snails are common pests. They’re especially common in wet, spring gardens. If you see signs of slugs or snails in the garden set some beer traps in among the vetch.
Beer traps are essentially little jars of beer set into the ground. The top of the jar should be about level with the ground. Slugs and snails love beer. They’re attracted to the smell of beer and drown themselves in it.
If you have ducks, you can also set them loose among the vetch. Ducks are great slug predators. Once the vetch is well established, your ducks won’t do much damage to it.
If you have a slug or snail problem in the fall, stick to beer traps. Ducks will devour young vetch as well as all the slugs.
When your hairy vetch is done growing and it’s time to clear out the cover crop, cut your vetch at the base and let it fall. Harvest after about two months of spring growth. Then, go through and cut the stalks as close to the soil as possible.
The stalks will dry out once they’re cut. After about a week, you can till the dead plant material in the soil and let it continue to release nutrients.
Plowing the old plant material into the soil helps improve the structure of the soil. It helps to improve drainability and slowy releases its nutrients into the soil. This green manure will provide a fantastic growing base for heavy nitrogen feeders like tomatoes and corn.
You can also feed vetch as fodder to goats, rabbits, and chickens, though never feed it to horses or cattle.