Oats are the seeds of any of several cereal grains in the genus Avena. They are used for food for people, and also as fodder for animals, especially poultry and horses. Oat straw is used as animal bedding and also sometimes used as animal feed.

Oats are often served as a porridge made from crushed oats or oatmeal, and are also baked into cookies. As oat flour or oatmeal, they are also used in a variety of other baked goods and cold cereals, and as an ingredient in muesli and granola. Oats may also be consumed raw, and cookies with raw oats are quickly becoming popular.

Oats are native to Eurasia and appear to have been domesticated relatively late. They are now grown throughout the temperate zones. They have a lower summer heat requirement and greater tolerance of rain than other cereals like wheat, rye or barley, so are particularly important in areas with cool, wet summers such as northwest Europe, even being grown successfully in Iceland. Oats are an annual plant, and can be planted either in the fall (for late summer harvest) or in the spring (for early autumn harvest).

Oat bran is the outer casing of the oat. Its consumption is believed to lower LDL ("bad") cholesterol, and possibly to reduce the risk of heart disease. Oats are also a safe grain for people with celiac disease (gluten intolerance). However, oats frequently get mixed up with small amounts of wheat during harvest and processing, so the EU officially lists them as a crop containing gluten. Oats from Ireland and Scotland, where less wheat is grown, are less likely to be contaminated in this way.

Oat straw is also used in corn dolly making, and it is the favourite filling for lace-making pillows.

Oat extract can be used to soothe skin conditions, e.g. in baths, skin products, etc.

Historical attitudes towards oats vary. In England they were considered an inferior grain, while in Scotland they were, and still are, held in high esteem. A traditional saying in England is that "oats are only fit to be fed to horses and Scotsmen", to which the Scottish riposte is "and England has the finest horses, and Scotland the finest men". The discovery of the healthy cholesterol-lowering properties has led to wider appreciation of oats as human food. Oats grown in Scotland command a premium price throughout the United Kingdom as a result of these traditions.

Agronomy

Oats are sown in the spring, as soon as the soil can be worked. An early start is crucial to good yields as oats will go dormant during the summer heat. Oats are cold-tolerant and will be unaffected by late frosts or snow. Typically about 100 kg/hectare (about 2 bushels are sown per acre), either broadcast or drilled in 150 mm (6 inch) rows. Lower rates are used when underseeding with a legume. Somewhat higher rates can be used on the best soils. Excessive sowing rates will lead to problems with lodging and may reduce yields.

Oats, barley, and some products made from them.

Winter oats may be grown as an off-season groundcover and plowed under in the spring as a green fertilizer.

Oats remove substantial amounts of nitrogen from the soil. If the straw is removed from the soil rather than being ploughed back, there will also be removal of large quantities of potash. Usually 50-100 kg/hectare (50-100 pounds per acre) of nitrogen in the form of urea or ammonium sulphate is sufficient. A sufficient amount of nitrogen is particularly important for plant height and hence straw quality and yield. When the prior-year crop was a legume, or where ample manure is applied, nitrogen rates can be reduced somewhat.

The vigorous growth habit of oats will tend to choke out most weeds. A few tall broadleaf weeds, such as ragweed, goosegrass and buttonweed (velvetleaf), can be a problem occasionally especially as they complicate harvest. These can be controlled with a modest application of a broadleaf herbicide such as 2,4-D while the weeds are still small.

Modern harvest technique is a matter of available equipment, local tradition, and priorities. Best yields are attained by swathing, cutting the plants at about 10 cm (4 inches) above ground and putting them into windrows with the grain all oriented the same way, just before the grain is completely ripe. The windrows are left to dry in the sun for several days before being combined using a dummy head. Then the straw is baled.

Field of oats in Hemingway, South Carolina

Oats can also be left standing until completely ripe and then combined with a grain head. This will lead to greater field losses as the grain falls from the heads, and also to harvesting losses as the grain is threshed out by the reel. Without a draper head, there will also be somewhat more damage to the straw since it will not be properly oriented as it enters the throat of the combine. Overall yield loss is 10-15% compared to proper swathing.

Late 19th and early 20th century harvesting was performed using a binder. Oats were gathered into shocks and then collected and run through a stationary threshing machine.

Earlier harvest involved cutting with a scythe or sickle, and threshing under the feet of cattle.

A good yield is typically about 3000 kg/hectare (100 bushels/acre) of grain and two tonnes of straw.