Hay is grass or legumes cut green and dried to feed livestock — "the horses get two slices of hay a night". Straw is the hollow stalk left over after grain is harvested, used mainly for bedding — "we spread fresh straw in the stable". Hay is food; straw is what the animal sleeps on.
The core difference
Both arrive as golden bales in a barn, which is why they are confused, but they come from different crops and do different jobs. Hay is a crop grown deliberately to be eaten: grass, clover, lucerne or a mix, cut while still leafy, dried and baled with the nutrition intact. Straw is a by-product: once wheat, barley, oats or rye have been threshed for their grain, the dry stalks that remain are baled as straw.
How to tell them apart by eye
- Colour: hay keeps a greenish or olive-brown tint from the leaf; straw is pale yellow to bright gold.
- Structure: straw stems are hollow tubes, and you can flatten one between finger and thumb. Hay is leafy, softer, and often has seed heads.
- Smell: good hay smells sweet and grassy; straw smells of very little.
- Weight: a hay bale of the same size is noticeably heavier.
The test
Ask: is it feed or is it bedding? If an animal is meant to eat it, it is hay. If it is there to be lain on, mucked out and composted, it is straw. In writing, if you could substitute "dried grass", use hay; if you could substitute "leftover stalks", use straw.
What each is used for
Hay feeds horses, cattle, sheep, goats, rabbits and guinea pigs through the winter, when grazing is gone. Straw is bedding for livestock, but also thatching for roofs, mulch on a vegetable bed, packing material, board and paper stock, and the raw material for straw hats and corn dollies.
The honest complication
Straw is not inedible. Cattle will eat it, and it is sometimes fed deliberately as bulk roughage or mixed into a ration. But it has little protein or energy, so an animal fed on straw alone will lose condition. That is the practical point behind the distinction: feeding straw where hay is needed is a real and serious mistake, not a matter of vocabulary.
The idioms, which run in both words
- Make hay while the sun shines — take the chance while conditions allow, because hay must be dried in dry weather.
- A needle in a haystack, hit the hay (go to bed), make hay of something (throw it into confusion).
- The last straw, clutching at straws, a straw man, a straw poll, drawing the short straw.
Note that the drinking straw takes its name from the hollow stalk — the shape is the point.
Frequently Asked Questions
Can horses eat straw?
They can eat small amounts as roughage, and some are bedded on it and nibble it, but straw has too little nutrition to replace hay. A horse kept on straw alone will lose weight.
How do I tell a hay bale from a straw bale in the barn?
Pull out a stem. Straw is a hollow, shiny gold tube with no leaf; hay is leafy, softer, greener and often has seed heads. The hay bale will also be heavier for its size.
Is straw just old hay?
No. They come from different crops. Hay is grass or legumes grown to be eaten; straw is the stalk left behind after cereal grain has been harvested. Age has nothing to do with it.