Hides and houses
Shelves and ledges
Foraging and toys
Cage accessories
Kits and bundles
Fairy forest
Spooky mischief
Sweetie stash
Game mode
Forest floor
Castles and cathedrals
Yes, guinea pigs can eat grass, and it is one of the best things they can eat. The RSPCA recommends fresh grass as often as possible, ideally every day, and the PDSA says hay and grass together should make up 85 to 90% of the diet. The one firm rule: never feed lawnmower clippings, which ferment and make guinea pigs ill.
| Safe? | Yes, a core food |
| How much | As much as they want, once used to it |
| How often | Daily, alongside unlimited hay |
| Best served | Growing, or hand-picked and fed fresh |
| Watch out for | Clippings, sprays, dog or cat mess, wild mushrooms |
Is grass good for guinea pigs?
Yes. Grass is what guinea pigs are built to eat. It is high in fibre, low in sugar, and the long chewing it needs wears down teeth that never stop growing. Burgess treats unlimited grazed grass as an equal to hay for the main part of the diet, and Woodgreen lists grass as a safe forage food.
Fresh grass also brings some vitamin C and plenty of water, and grazing is good exercise and enrichment. It does not replace hay, though. Grass stops growing in winter, a run can be grazed bare in days, and wet grass can be too much at once.
How much grass can a guinea pig eat?
Once they are used to it, as much as they like. Getting there is the careful part. A guinea pig that has been on hay all winter needs time to adjust, because a sudden change of diet can upset the gut. The RSPCA advises introducing new foods gradually, so we'd start with 15 to 30 minutes of grazing, or a small handful of picked grass, and build up over one to two weeks. Keep hay available the whole time.
How to graze guinea pigs safely
- Check the lawn. Use only grass that has not been treated with weed killer, lawn feed or pesticide, as the PDSA advises.
- Do a morning sweep. Pull up any mushrooms or toadstools and pick up droppings from wild animals or pets.
- Use a secure run. Give shelter from sun, rain and wind, and cover the top to keep out predators.
- Start slowly. Short sessions at first, building up over a couple of weeks.
- Move the run. Shift it to fresh grass every day or two so it never gets grazed bare or soiled.
Clippings, picked grass, potted grass and dried grass
| Form | Okay? | Why |
|---|---|---|
| Growing grass | Yes | Ideal, eaten fresh at its own pace |
| Hand-picked grass, fed at once | Yes | Pick with scissors or fingers and give the same day |
| Pots or trays grown indoors | Yes | The RSPCA suggests these for indoor guinea pigs |
| Dried grass and hay | Yes | The everyday base of the diet |
| Lawnmower clippings | Never | Ferment quickly and cause bloating and diarrhoea |
| Roadside or park grass | We'd avoid | Fumes, sprays and dog mess |
Even a small pile of mower clippings can make a guinea pig very ill. If yours has eaten some, take them away, give hay and water, and ring your vet if they stop eating, bloat or have diarrhoea.
Who should take it slowly?
Guinea pigs new to grass, babies, and any with a sensitive stomach or recent gut trouble should start with very small amounts. Very wet grass after heavy rain is best kept to shorter sessions.
Other foods to go with grass
Grass questions
Can guinea pigs eat grass clippings?
No. The RSPCA says lawnmower clippings will upset a guinea pig's digestive system and make them ill, and the PDSA explains that cut grass ferments quickly. Even a small pile can cause bloating and diarrhoea. Only offer grass that is growing, or that you have just picked by hand.
Can guinea pigs live on grass instead of hay?
Only when they have unlimited access to good grass, which Burgess counts as an alternative to hay. In practice most guinea pigs need hay too, because grass stops growing in winter, gets wet and runs out in a small run. Keep hay available at all times, even on grazing days.
Can guinea pigs eat grass from the park or roadside?
We'd avoid it. The PDSA warns against grass from high-traffic areas or anywhere treated with weed killer or pesticide, and Woodgreen adds places where dogs or cats toilet. You rarely know what a park verge has been sprayed with. Your own unsprayed lawn, or grass grown in a pot, is safer.
Can indoor guinea pigs have grass?
Yes. The RSPCA suggests giving indoor guinea pigs pots of fresh, growing grass. You can grow trays of grass from seed on a windowsill, or hand-pick a bunch from an unsprayed lawn each day and give it fresh. Take away any that wilts.
