Add it to your home screen and it opens full screen: no browser bars, one tap away, and everything stays signed in. Free, nothing to download from an app store.
- Tap the Share button in your browser
- Scroll down and choose “Add to Home Screen”
- Open GrowSomeFood from your home screen
- Open your browser’s menu
- Choose “Add to Home screen” or “Install app”
- Open GrowSomeFood from your home screen
Hairy Vetch
The cold-hardiest and one of the most powerful nitrogen-fixing cover crops: a sprawling, viny winter-annual legume that overwinters where others fail, blankets the soil, feeds bees with purple bloom, and delivers a big shot of nitrogen when terminated - but it self-sows aggressively, so it's planted deliberately and cut before it seeds.
Safety notes Hairy vetch is grown to build the soil, not for eating. Its SEEDS are toxic to humans and can be poisonous to poultry and some livestock, and grazing the FOLIAGE can cause a systemic toxicosis in cattle - it is a green-manure and forage-management plant, not a food. Do not eat any part. Its main garden caution, though, is behavioral: it self-sows and can become a weedy volunteer, so it's flagged for deliberate, managed planting.
Overview
Hairy vetch is a soil-building heavyweight - one of the most effective nitrogen-fixing cover crops a gardener can grow, and the most cold-hardy of the common legume covers. A sprawling, viny annual with soft, ferny, hairy foliage and grasping tendrils, it partners with soil bacteria to fix large amounts of nitrogen from the air, then hands that nitrogen to the following crop as free fertilizer when it's tilled in or crimped down. It overwinters (to about -15F) where crimson clover and field peas would die, extending legume cover into colder zones, and its late-spring flush of violet-purple flowers is a valuable nectar source for bees and beneficial insects.
The one thing to knowHairy vetch is a soil-building heavyweight - one of the most effective nitrogen-fixing cover crops a gardener can grow, and the most cold-hardy of the common legume covers.
Quick facts
- Sprouts in
- 12 daysRange: 7–20 days
- Soil temperature
- 60 °FRange: 45–75 °F
- Height
- 24 inRange: 12–48 in
- Spread
- 12 inRange: 6–24 in
- Cold
- Takes hard frostdamaged below -15°F
- Heat
- Struggles above 90°F
- Life cycle
- Annual
- Save seeds
- About 260 days after plantingRange: 200–320 days
- Self-sows
- Yes, expect volunteers
- Soil
- Well-drained
- Water
- Medium
- Plant spacing
- 3 inRange: 1–6 in
When to plant
Nothing is open today. Fall sowing opens 10 months, Aug 11 to Sep 5.
- Direct sow Aug 11 – Sep 5 Opens in 296 daysAbout 11 weeks before to 7 weeks before your first frost (Oct 25 here)Often sown with a grass 'nurse crop' like cereal rye or oats in late summer/early fall - the grass gives the viny vetch something to climb and adds carbon, while the vetch fixes nitrogen. The classic rye-vetch cover mix.
- Direct sow Aug 26 – Sep 25 Opens in 311 daysAbout 9 weeks before to 4 weeks before your first frost (Oct 25 here)THE main use: sow in fall (about 30-45 days before hard frost) as an overwintering nitrogen cover crop. Hairy vetch is the most cold-hardy legume cover (to about -15F), so it overwinters where clover and peas can't, then surges in spring - terminate at bloom, before seed set, for a nitrogen boost.
Frost here: last around Apr 10 (Mar 27 to Apr 24 most years), first around Oct 25. Zone averages, your own yard may run a week or two either way.
Life stages
From the first start to harvest
Follow the growing sequence. Choose a stage to see its care and signs to watch for.
Stage 1 of 5 · The growing sequence
Germination
Day 0 to 12 from sowing
Care at this stage
-
Sow into a moist bed and cover the seed
Broadcast the fairly large seed onto a firm, moist bed and rake it in about half an inch - vetch needs decent soil coverage and moisture. Fall sowing into cooling, moist soil is the standard.
-
Inoculate for nitrogen fixation
Use seed inoculated with the correct vetch/pea (Rhizobium leguminosarum) bacteria so the roots nodulate and fix nitrogen. Most cover-crop seed comes pre-inoculated; add inoculant if sowing into ground new to vetch or peas.
Stages can overlap; weather, variety, and growing conditions change the pace.
Watch out for
4 to know. 1 is high-risk: Weedy Reseeding / Volunteers. 1 is active in October.
Weedy Reseeding / VolunteersSeverity High DisorderSeason: May–AugVolunteer vetch seedlings and vines appearing in later crops and along edges, climbing and tangling wanted plants, over one or more seasons after a stand set seed.
Not a pest or disease but a behavioral hazard - the whole reason for its Caution flag; terminate before seed set and it's easily managed.
Volunteer vetch seedlings and vines appearing in later crops and along edges, climbing and tangling wanted plants, over one or more seasons after a stand set seed.
Pull or cultivate volunteers while young, mow before they seed, and stay vigilant over a season or two, since the hard seed bank persists in the soil.
Terminate hairy vetch at early-to-full bloom, BEFORE any seed sets - this is the single most important practice; don't let a cover crop go to seed unless you deliberately want a self-reseeding stand.
Hairy vetch's defining problem: allowed to set seed, it drops hard seed that persists in the soil and germinates over several seasons, producing volunteer vetch that scrambles up later crops and spreads into nearby ground - the reason it's flagged for careful, deliberate planting.
Crown RotSeverity Medium DiseaseSeason: Nov–FebA plant that fails to green up or emerge in spring when everything around it does - the most common way this gets discovered, and by then it is already too late.
For hairy vetch this is the main way to lose a cover: it wants moist but well-drained ground, and a mild wet winter on heavy soil can thin or destroy the stand. Growing it with a grass nurse crop improves the stand's airflow and structure.
A plant that fails to green up or emerge in spring when everything around it does - the most common way this gets discovered, and by then it is already too late. Stems that wilt, blacken, and collapse in wet weather while the soil is clearly damp rather than dry. A crown that is soft, dark, brown, or mushy when you press or lift it, sometimes with a foul smell, instead of firm and pale. New growth that pulls away from the crown with almost no resistance. Clumps browning and going hollow in the middle while the outer growth stays alive. In stands and cover crops, patches wilting, yellowing, and thinning out after wet spells or over a mild wet winter.
There is usually no cure once the crown itself has rotted: the plant is lost, and the job is to save what you can and fix the site. Lift it, cut away every soft, dark, rotted part with a clean blade back to firm tissue, and replant only healthy divisions or firm outer growth into fresh, sharply drained soil or medium. On potted and specialist plants, repotting into fresh airy medium and keeping them drier with better airflow gives the best chance, though a badly rotted crown is usually beyond saving. Bin the rotted material rather than composting it. Replant somewhere better drained rather than back into the same wet spot - or start again from seed, cuttings, or self-sown seedlings, which is the realistic option for anything that resents being moved at all.
Drainage and airflow at the crown are everything. Match the plant to the site first: a dry-adapted perennial planted in heavy or enriched ground is on borrowed time whatever else you do. In wet or clay soil, plant on a slope, berm, raised bed, or gritty rock-garden site so water drains away from the crown rather than standing over it. Set plants at the right depth - never bury the crown - and keep mulch, dead leaves, and debris pulled back from it rather than piled against it, since damp material resting on the crown is a common trigger. Do not overwater, and ease right off during dormancy, when a resting plant wants to be barely damp rather than wet. Give crowded plantings enough space and airflow to dry out, and do not sow a stand too thickly. In cold, wet climates, divide in spring rather than fall, so plants are not recovering from surgery through the wettest months.
Crown rot is the rotting of a plant at the crown - the growing point where the stems meet the roots, right at or just below soil level. Soil fungi and water molds that live in most ground attack that tissue whenever it sits wet, cold, and airless, and because the crown is the one part a perennial cannot regrow from, losing it usually means losing the plant. It is above all a winter problem: a plant that survives hard frost perfectly well in dry ground rots out in a wet one, and the classic story is a perennial that simply never comes back in spring. Dry-adapted plants growing in heavy or over-improved soil are the most vulnerable, along with anything that has mulch, wet leaves, or piled debris sitting against the crown, and anything planted too deep.
Damping-OffSeverity Low DiseasenowSeason: Sep–NovSeedlings that fail to emerge or collapse at the soil line soon after germinating, and thin, patchy establishment in cold wet conditions.
An establishment-stage issue in cold wet soil - a warm, moist, well-drained bed at the right time avoids it.
Seedlings that fail to emerge or collapse at the soil line soon after germinating, and thin, patchy establishment in cold wet conditions.
None for affected seedlings; reduce watering, improve drainage and airflow, and resow more thinly if needed.
Sow into warm-enough, well-drained, moist (not soggy) soil with good seed-to-soil contact, and don't sow too deep or too early into cold ground.
A seedling rot that collapses young desert marigold seedlings sown too thickly or kept too wet in cool conditions - a minor issue easily avoided by lean, well-drained sowing and careful watering.
Pea AphidSeverity Low PestSeason: Apr–JunColonies of large pale-green aphids packed onto shoot tips, tendrils, and flower stalks, thickest on the softest new growth.
Seldom a real problem - hairy vetch attracts abundant aphid predators and is more often part of the pest solution than a victim.
Colonies of large pale-green aphids packed onto shoot tips, tendrils, and flower stalks, thickest on the softest new growth. Aphids dropping off the plant the moment you brush against it - a habit fairly specific to this species. Sticky honeydew on the foliage below, ants running the stems, and white cast skins where a colony has been. Yellowing, stunting, downward-rolled leaves, or a mottled stand that does not grow away, which points to a virus the aphids brought rather than the feeding itself.
On a cover crop, usually nothing at all - the predators arrive and the stand outgrows it. Knock heavy colonies off with a jet of water, or pinch out and remove the worst-infested tips. Insecticidal soap sprayed directly onto the insects works if a stand is genuinely being checked, but it also hits the beneficials, so keep it to spot treatment. Never spray a stand you intend to pick shoots or flowers from without checking the product label for that use and its pre-harvest interval.
Encourage the beneficial insects that legume flowers already draw, and skip broad-spectrum sprays that remove them. Do not over-feed nitrogen, since soft lush growth is what the colonies build on - and a legume should not be getting nitrogen anyway. Check the growing tips weekly through spring, and rub out the first colonies by hand while they are small. Where virus has been a recurring problem in a legume rotation, avoid planting a new stand immediately downwind of an old one, since that is how the winged aphids move.
The pea aphid is a large, long-legged, pale-green aphid that specializes on legumes - peas, vetch, clover, alfalfa, lentil, faba bean - and colonizes the growing tips, tendrils, flower stalks, and developing pods. It builds fastest in the mild weather of spring, when a handful of overwintered females can become a coating within two weeks, and it drops off the plant readily when disturbed. On a vigorous cover-crop stand the feeding itself is usually cosmetic and is held in check by the ladybugs, lacewings, hoverflies, and parasitic wasps that legume flowers attract. What matters more is that it transmits viruses between legumes, including pea enation mosaic and bean leafroll, which stunt and yellow a stand out of all proportion to the number of insects present.
Good & bad neighbors
Plant nearby
-
The definitive hairy-vetch partner: cereal rye gives the sprawling vetch a sturdy structure to climb, adds carbon and weed suppression, and together they make the celebrated roller-crimped no-till mulch - the single best way to grow hairy vetch.
-
Terminated at bloom, hairy vetch leaves a large nitrogen credit and rich mulch ideal for heavy feeders transplanted after it - the crimped rye-vetch mulch into which tomatoes and squash are planted is a signature no-till technique.
-
Oats serve as a fast nurse crop and support for hairy vetch, establishing quickly and giving the vine something to climb; in cold zones the oats winter-kill while the hardier vetch carries the nitrogen cover on.
-
Hairy vetch is commonly grown with small grains as a grass-legume cover mix, the grain providing structure and carbon while the vetch fixes nitrogen and balances the mix.
Varieties · 4
You pick one when you add Hairy Vetch to your garden. Its days to maturity set your harvest window.
Common Hairy Vetch
The standard hairy vetch grown as an overwintering nitrogen cover crop and green manure: extremely cold-hardy, a heavy nitrogen fixer, and a good bee plant, but a vigorous self-sower to terminate before seed set.
Variety details for Common Hairy Vetch
Sprawling, soft, hairy ferny foliage with tendrils and one-sided clusters of violet-purple flowers.
cover-cropnitrogen-fixervery-hardyself-sowingThe all-purpose choice for cold-region soil-building.
Purple Bounty
An improved early-flowering hairy vetch (a USDA release) selected for earlier bloom and maturity, which lets you terminate sooner and fit it into tighter rotations - a real advantage for capturing nitrogen before the following crop and reducing the risk of it setting seed.
Variety details for Purple Bounty
Vigorous cold-hardy vetch with earlier violet-purple bloom than common types.
cover-cropearlyimprovednitrogen-fixerPurple Prosperity
Another improved early, uniform-blooming hairy vetch bred for earlier, more consistent flowering and good winter-hardiness - chosen, like Purple Bounty, to allow earlier spring termination and tidier management of this vigorous cover.
Variety details for Purple Prosperity
Uniform, early-blooming cold-hardy vetch with purple flower clusters.
cover-cropearlyimprovednitrogen-fixerHairy Vetch + Cereal Rye Mix
Not a single variety but the classic cover-crop pairing sold as a mix: hairy vetch with cereal rye.
Variety details for Hairy Vetch + Cereal Rye Mix
A tangled stand of upright rye interwoven with purple-flowered climbing vetch.
cover-cropmixnurse-cropno-tillThe rye gives the viny vetch structure to climb and adds carbon and weed suppression, while the vetch fixes nitrogen - the basis of the celebrated roller-crimped no-till mulch system. The best way for many gardeners to grow hairy vetch.
Grower tips
Notes from growers, tagged with the zone they grow in. A person reads every post before it appears.
Nobody has posted about Hairy Vetch yet. The first one usually saves someone a season.
Free account. Your post shows your grower name and zone, never your email.