Ornamental · Poaceae
Oats
Avena sativa
A speedy, good-natured cool-season grass that races to fill three jobs at once: cover for the soil, grain for the feed bin, and cat grass for the windowsill.
Full sun
Every 3–7 days
60–120 days
USDA 2–9
Overview
Oats rank among the easiest grasses going, and that is a big reason the one plant charges into so many jobs. The same Avena sativa turns into a cover crop, livestock forage, the grain in a breakfast bowl, and the cat grass grown for pets to nibble. The only thing that shifts from one job to the next is how you sow it and manage it.
This cool-season annual hits its stride in cool, moist weather and stalls out in heat and drought. It bolts up fast, throws down quick weed-smothering cover, and grabs loose nutrients before rain can flush them away. Pair it with a slow legume such as peas or clover and the oats jump in as a nurse crop, sheltering the seedlings, then dying back to hand over the bed right on cue.
Where winters bite hard enough, oats die back on their own and save you the whole chore of ending the stand. Where they do not, the plant drives through winter and sets seed, so you mow or till before it heads out. Nailing down which side of that line you garden on is the single most useful move to make before you sow, and once you have it, the rest just rolls.
Care
The short version: oats jump up fast in full sun and cool, moist soil, with little or no extra feeding. Sow the seed straight into the ground, keep it from drying out, and watch for warm winters that let the stand reseed.
Light
Oats crave full sun and crop best out in the wide open. They will put up with a bit of partial shade, but push past that and the stand thins out and loses its punch.
Water
As a cool-season grass, oats want it cool and moist and hold up poorly in heat or drought. Keep the soil from drying out, since dry spells stress the plant and clip both cover and yield.
Soil
Barely any cereal matches oats for being so adaptable. They lean toward a well-drained loam but take poor, somewhat acidic, and even wet ground better than most grains, sailing through a pH anywhere from 4.5 to 8.0.
Temperature
This is a tough cool-weather plant that grows across a wide range, from about 21°F to 84°F (-6°C to 29°C). It germinates in chilly soil and does its best work before summer heat cranks up.
Humidity
Plain outdoor humidity is all oats ask, so there is no number to chase. Good airflow does far more, since crowded, damp stands roll out the welcome mat for the rusts and other leaf diseases.
Feeding
Oats want next to nothing, and as a cover or nurse crop they often need no fertilizer at all, especially in a fall or legume-mix sowing. Go light on the nitrogen, since too much whips up soft growth that flops over.
Pruning
There is no pruning to bother with. In mild-winter regions, mow or till the stand before it sets seed to shut down weedy volunteers, while in cold climates the plant dies back on its own and needs nothing.
Repotting
none
Size & spacing
A stand shoots up about 2 to 4 feet (60 to 122 cm) tall, with each plant claiming just 6 to 12 inches (15 to 30 cm) across. Sow it thick, since oats grow as a close stand rather than spaced out like a garden vegetable.
When to plant
Oats run on cool weather and a frost clock. Sow in late summer to early fall, about 40 to 60 days before your first killing frost so the cold can take the stand down, or fire off another sowing in early spring. The plant heads up in spring to summer, with grain ready to harvest by mid to late summer.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Not typical; direct sown outdoors
- Plant: Late summer to early fall (40 to 60 days before first killing frost, to winterkill) or early spring
- Harvest: Open drooping branched panicle of spikelets in spring to summer; grain harvest mid to late summer
Hardiness
USDA hardiness zones: 2–9
Temperature: down to -46°C
Troubleshooting
Oats throw very little at you, all the more so grown as a short-term cover crop. The few problems that crop up tend to hit the whole stand rather than one plant. Match what you spot to the notes below and jump on it before it spreads.
Grazing cattle, sheep, and goats take ill from stressed forage
Good news first: the plant itself is no poison. Hit oats with drought, frost, or a heavy shot of nitrogen, though, and the forage can stack up nitrate, and that nitrate is what knocks grazing ruminants like cattle, sheep, and goats. So test stressed or heavily fed forage before you graze it, keep animals clear of drought- or frost-stressed stands, and lean on ensiling, which drives nitrate down. The standing plant and the grain stay perfectly good for pets and people.
Fix:
- Test stressed or heavily fertilized forage for nitrate before grazing or feeding
- Ensiling can reduce nitrate levels
- Avoid grazing drought- or frost-stressed stands
Oats power through winter and reseed instead of dying back
A mild winter flips the script on you. The stand never catches the hard cold it needs to die off, so it springs back green, shoots up heads, and scatters seed for next year. Oats reliably die back only in Zone 6 and colder and across much of Zone 7. Anywhere warmer, get ahead of them and mow or till before the plants set seed instead of leaving it to the frost.
Fix:
- Mow or till the stand before seed set
- Terminate by herbicide or mowing soon after the vegetative stage
- Do not rely on winterkill termination in mild-winter areas
Orange rust flecks, dark powdery spore masses, or yellow dwarfed leaves
These are the usual cereal troublemakers. Crown and stem rust flare up as orange-brown pustules, smut throws dark powdery masses, and barley yellow dwarf virus, hauled in by aphids, paints the leaves yellow and red as it stunts the plant. Rotate clear of other cereals, launch with clean or resistant seed, and stay on top of aphids. Run oats as a quick cover crop, though, and they barely take a scratch worth acting on.
Fix:
- Rotate away from cereals
- Use clean, treated, or resistant seed where available
- Control aphids that vector barley yellow dwarf
Tall stems topple and stretch out flat across the ground
When the stand suddenly lies down flat, that is lodging, and it usually traces back to soil that ran too rich or caught too much nitrogen, pushing soft, top-heavy growth that a hard rain or gust flattens fast. So dial the extra nitrogen right back when oats run as a cover or nurse crop. And if grain was never the plan, lodged oats cost you nothing, since a downed stand still smothers weeds and packs down into a handy mulch.
Fix:
- Avoid extra nitrogen fertilizer when grown as a cover or nurse crop
- Mow tall growth before it lodges if managing biomass
Toxicity
Oats sit about as safe as a plant gets, and that makes them a joy to grow around a busy household. The grain feeds people and animals alike, and the grass is grown specifically as cat grass for pets to nibble, so nothing here is poisonous to cats, dogs, horses, rabbits, birds, livestock, or children. The one catch rides with grazing ruminants, since drought- or frost-stressed forage can carry nitrate worth testing for.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats Safe
This is the star cat grass, grown specifically for cats to nibble. A little chewing does zero harm and can even help a cat clear a hairball.
Dogs Safe
Dogs can graze the blades with no trouble, and the very same pet grass grown for cats works a treat for them too. Plain oats and oat grass land on no toxic-plant list.
Horses Safe
Oats have fueled horses as a feed grain for ages, and the grass is fine to graze. Nothing in the plant will poison them.
Rabbits Safe
Rabbits thrive on oat hay and fresh oat grass, both an everyday staple of their diet.
Livestock Safe
The plant itself is wholesome forage and packs no toxin. The one thing to track is nitrate, which can stack up in oats stressed by drought, frost, or heavy nitrogen, so test any iffy forage before you turn ruminants out on it.
Birds Safe
Oats are a go-to bird feed, and chickens and wild birds tuck into the grain and peck at the grass freely.
People Safe
The grain is a kitchen staple, eaten as oatmeal, oat flour, and loads more. The plant is grown for people to eat.
Like other cereal grasses, drought- or frost-stressed oat forage can accumulate nitrates that may harm grazing ruminant livestock, but the plant is not poisonous to pets or people.
Varieties
Oats come in a handful of types sorted by season and end use, and these are the ones worth telling apart.
Spring oats
The go-to type, sown in spring or late summer, racing to head without any cold spell and dying back once hard frost lands.
Winter oats
Tougher types built for mild-winter regions, where they push through the cold and head the following spring.
Forage / hay oat varieties
Bred to pump out heavy leafy growth, like ForagePlus, and cut for hay, silage, or grazing rather than grain.
Hull-less (naked) oats
These thresh clean out of the hull to leave a bare groat that shines in both feed and food.
Companions
Oats earn their keep beside slow-starting legumes, where they nurse the young plants along and then bow out as the season turns.
Plant near
Field peas: Oats serve as a nurse crop, providing quick weed-suppressing cover and support while the slower legume establishes.
Clover: Oats nurse establishing clover, suppressing weeds and scavenging nutrients while winterkilling to release the legume.
Hairy vetch: Oats added to slow-establishing vetch improve legume survival and provide cover that winterkills in many areas.
How to propagate
Oats grow from seed and nothing else, sown right where they are meant to grow.
SeedEasy
Late summer to early fall or early spring · Germinates quickly (germinates at about 38 degrees F); usable cover in 6 to 10 weeks
Oats take off from seed alone, sown straight outdoors in late summer to early fall or in early spring. Drill it at about 60 to 75 pounds an acre, or broadcast 80 to 100 pounds an acre, and tuck the seed half an inch to an inch deep. It fires up in cool soil down to about 38°F (3°C) and hands you usable cover in 6 to 10 weeks, which is exactly what makes it such a quick, cheap, rewarding crop to kick off.
Myths
Cover-crop oats surely can't be the same plant as food oats or the cat grass grown for pets.
Not so, this one plant pulls off every job. Cover-crop oats, forage and hay oats, grain oats, and the grass grown for cats to nibble are all the same plant, Avena sativa. The only thing that shifts is how you sow it and run it.
Oats are sure to winterkill and finish on their own, so the stand never needs terminating by hand.
Handy idea, but it only holds where the cold really bites. Oats die back on their own where winters turn cold enough, roughly Zone 6 and colder and much of Zone 7, down into the low 20s degrees F. In milder spots they power through winter and set seed, so you have to mow or till the stand before it heads out.