The Surprising Truth About Grass & Guinea Pigs (Can They Eat It?)

Since guinea pigs are herbivores, it’s only natural to wonder if they can eat grass. I mean, there’s so much of it around, right? Is there anything wrong with taking your guinea pig for an outdoors stroll to nibble on some fresh, green grass?

Guinea pigs can safely eat grass, but there are some precautions that should be taken. Make sure that the grass isn’t contaminated with pesticides or urine from animals like foxes or dogs. If your guinea pig hasn’t eaten grass before, you need to give them a little bit of it first and then slowly increase the amount.

can guinea pigs eat grass

Grass is a pretty common thing to see in our yards and gardens, which means it’s tempting for some animals-including our pet Guinea Pigs! Healthy, untreated grass can be a great treat for your guinea pig and is certainly better than some other, sugary treats!

But before you give your furry friend a fresh green snack, it’s important to know the risks that might come with eating grass.

Find out more about the dangers of giving your fur balls grass in this post as well as ways to feed grass to them safely!

Let’s dive in!

How To Safely Feed Grass To Guinea Pigs

can guinea pigs eat grass

Most pet parents have heard that their furry friends need unlimited hay to eat, but have no idea about grass. Both grass has lot of health benefits for cavies.

Actually, grass is their natural diet, and it contains a lot of fiber (to keep their digestive tract in great shape) and it’s a great source of Vitamin C.  Things that piggies need.

Its rough, tough texture helps them grind down their teeth (something that is necessary for their overall dental health and physical health).

The problem is that cavies need a constant supply of it (if you’re not feeding them unlimited hay, that is).

There aren’t many pet parents that can provide their fur babies with unlimited grass, unfortunately. A lot of us don’t live in areas where grass for guinea pigs is readily available.  Hay – which can be sourced year round – is usually the preferred staple.

But, that doesn’t mean that you can’t let your little friends enjoy some fresh grass when it’s available.

Before you run outside and grab a few blades of grass for your pet friends to munch on, here are some things that you should keep in mind:

  • Introduce grass slowly for a few days or weeks. It may seem counterintuitive, but if you do it too quickly your piggies may get sick from ingesting too much roughage at once (their tummies need to adjust gradually). First give them a little and then increase it a bit every day until they get used to it.
  • Only give your fur babies grass that you have cut with scissors or pulled by hand. Lawn clippings should be avoided because lawn mower cut grass ferments very quickly. It could make your piggies sick with bloat. Plus, those cuts have just been through a greasy, oil machine (I mean, ewww, who wants to eat that?)
  • Sopping wet grass and frozen grass are a big no-no for feeding to your piggies. Both can make them very sick and possibly even cause death.
  • Grass sprayed with toxic chemicals, herbicides or pesticides should be avoided for health reasons. Get untreated grass from your own yard, a park (if you trust that the environment is pesticide free there) or a friend’s yard.
  • Avoid sourcing grass from overly damp, soggy areas (mold alert!), from the sides of busy roads (chemicals), and from areas where there could be contaminants (dog or fox pee, feces, etc.). Also, check the grass for things like insects and parasite eggs that’ll be harmful to your fur babies.
can guinea pigs eat grass

Can Guinea Pigs Graze On Fresh Grass Outside?

Lot of pet parents take their guinea pigs outside to graze on fresh grass from time-to-time. But, it’s important to make sure that they’re well-protected (from predators and the weather) while they’re outside and that the grass is safe for your pet’s consumption.

However, there are some dangers associated with letting cavies graze freely on fresh grass.  

  • Always keep an eye on your pet while they’re outside, and preferably only let them graze in an fenced-in area or inside a safe enclosure like a guinea pig run. A run is ideal for keeping your pet safe, as it allows them the freedom to move about in the fresh air and sunshine without having to worry about predators like dogs, hawks or eagles – while you keep an eye on them.
  • Make sure that the weather is sunny and that the ground doesn’t get too hot or cold for them. If you touch the ground and it feels chilly to you, then it may be too cold for your pet to stand on. Cold ground could cause hypothermia or frostbite if the temperature is low enough (or else might cause them to get a chill which would make them more vulnerable to other diseases).
  • Try to pick an area with a little shade. Piggies can easily overheat in the hot sun (yep, piggies getting heat stroke is a thing). Actually, pigs like to be in the shade. You can make them feel safe by covering half of their outdoor run with a cover – which means they’ll be more active.
  • Don’t let your piggie forage on grass or plants that you’re not familiar with. That’s a great way to pick up parasites or toxic plants that could make your pet sick. A good rule of thumb is–if you don’t know what it is, then don’t let piggies eat it!
  • If your lawn is soggy and damp, extended periods of time outside can lead to wet bellies and legs, which could eventually lead to death. To prevent this, pay attention to the weather before letting them out for a long period of time. Sometimes the sun will dry out grass even if it’s just a little bit damp.

Is Grass Good For Cavies?

Grass is as good for guinea pigs as hay is – shoot, maybe even better. There are a couple of reasons why grass is so good for guinea pigs.

First, there’s the obvious reason that grass contains Vitamin C, which many cavy owners are well aware of already (although few people know exactly how much Vitamin C is in grass).

But what you may not have heard about is all the other great stuff that comes along with grass – and not just nutritional benefits.

Read on and you’ll find out about the surprising benefits of grass that go beyond Vitamin C.

Guinea Pigs Need To Chew

There are a few more benefits to feed guinea pigs grass than just extra nutrition. Guinea pigs need to chew, just like humans do. And for reasons we’re not entirely sure why, this is even more important than you might think.

Studies have shown that cavies who aren’t given enough chewing material (such as hay) can suffer from stress and boredom which can lead to hair-chewing, bar biting, and depression.

Not to mention their jaw and teeth will suffer as a result if they don’t have enough material to chew.

Guinea pig teeth constantly grow, so they need to always be given material of some sort to chew on. Grass is perfect for this, so your fur babies can chomp away at the grass, not only strengthening their jaw but also re-shaping their teeth as they chew.

Piggies Need Foods That Jumpstart Their Digestive System

Besides being something for your cavy to chew on, grass serves yet another purpose – to help your cavy digest their food. Grass is packed with lots of fiber, so if you throw in a handful of grass with your guinea pig’s regular hay it will help their digestive system.

This is one of the reasons why fresh greens (or our snazzy, standby hay) should make up at least 80% of your goat’s food intake.

Exercise In Treat Form

The cavies of owners that allow them to graze grass in a safe area not only benefit from the grass. They also benefit from the physical exercise that they get while they eat.

And combining food and exercise is one of the best ways to keep cavies healthy, happy and trim (well, trim for a piggie anyway), just like for us humans.

Instead of being confined to their enclosure to eat their food (e.g veggies and hay) – which is usually put in one spot, piggies who graze get a chance to explore as they nibble, therefore getting exercise while they eat.

So, if you have a piggie with health issues from obesity, this is a gentle way to get you little friend up and moving.

As a bonus, when cavies are allowed to play outside of their cage in an area that’s safe for them, they also get some sunlight (a little shady light is fine, but never direct light) and fresh air.

When you’ve got a nice field of fresh green grass growing in your yard (or if you’re lucky, maybe even in the kitchen), allow your piggies to graze and get exercise at the same time!

So, How Much Grass Can My Cavy Eat?

A lot! Once your guinea pigs have gotten used to the grass, you can give them as much of it as they want. Some owners even like to have a little patch where the grass is allowed to grow long so their piggies can munch on that instead.

Remember though, you also need to make sure your guinea pig gets enough hay and food in general — and that’s especially true if they’re grazing outside of their cage. Because it can be harder to tell how much your cavies are actually eating.

If you’re hand feeding the grass, keep in mind that if you’re not sure, it’s better to give your guinea pig too much grass than it is to give them too little.

Thinking about adding a piggie to your family or want to brush up on the essentials? Gotcha covered. What you need is a reliable, “all-in-one” resource to refer to when you’re struggling. A Beginner’s Ultimate Guide To Guinea Pig Care is a starting point with all the basics and more to get you on your way!

Do Guinea Pigs Like Fresh Grass?

Guinea pigs definitely enjoy fresh grass.

And it’s a good thing, too. It’s an important part of their diet – jam-packed with vitamins and nutrients that’ll boost your guinea pig’s immune system.

Fun fact: It’s one of the few food sources they can enjoy on a daily basis.

But, when guinea pigs eat grass for the first time, start with a small handful and gradually increase the amount of grass they consume. 

Avoid giving them larger amounts at one time because you may end up with an unusually ill pet.

How Much Grass Should I Feed My Pet Guinea Pig?

Introducing fresh grass to a cavies’ diet is pretty simple. They can actually eat as much as they want as long they’re used to it.

Offer your cavy just a few blades of fresh grass per day to start. Watch his/her reaction and you’ll know if he likes the food or not.

Once he’s had enough, increase the amount gradually until he’s eating as much as he wants. 

Just like hay, piggies can have an unlimited amount of grass. As long as there are no signs of diarrhea, give them what they want!

How To Grow Fresh Grass For Your Cavies

So, maybe you want your little friends to have some grass to nibble on, but you don’t want to worry about them getting sick from it.

Or maybe you want you cavies to have access to grass year round (it’s a little more work on your end but it is totally worth it).

Whatever the case, keeping a supply of grass safe for your piggies by growing grass indoors is fun and easy to do.  

You can grow grass on windowsills.

All. Year. Round. (cue the hypnotic swooshing of a gently flowing stream).

There’s lot of types of grass you can feed your piggie (e.g. orchard grass, millet grass, fescue, and other types of hay grass). 

Wheat grass (also know as cat grass) is the most popular – full of Vitamin C and well-liked by piggies. 

And like all grasses, it’s sugar free, which will help keep your piggie’s blood sugar levels stable.

(The Vitamin C is important because cavies can’t produce their own and they’ll get scurvy-a potentially fatal disease-without it being added to their diet.)

Follow these steps to grow some first-rate grass for your little friends.

  1. Get some grass seeds and some “pet-safe” grass feed.
  2. Plant the seed in some compost. Just sprinkle some seeds in a tray, cover with about an inch of soil.
  3. Water every 2 or 3 days. It’ll take a couple of weeks for the grass to start sprouting. They regrow very well after you’ve cut them, too!

Easy, huh?

Here’s a video to help you out with the process.

And another on how to do it without (gasp!) soil. This might appeal to you if you’d rather limit the mess that you have to deal with and avoid the extra cost of soil.

Is Fresh Grass As Good As Hay For Guinea Pigs?

Fresh grass is definitely as good as hay for guinea pigs. Grass is part of their natural diet and they will eat it just like any other food source.  Only give them clean grass to eat.  

If My Guinea Pigs Are Eating (Or Grazing For Grass), Do They Still Need Hay?

Always offer unlimited hay to your cavies. That should always be a constant. But, you might not need to give them as many vegetables.

If your piggies are grazing outside for 10+ hours each day (lucky piggies), you might not need to give them a full cup of fresh veggies every day.

But, if you’re only giving them a handful of grass blades – here and there, then YES, they still need the fresh veggies. 

There’s minerals and other nutrients that your piggies need that can only be found in raw produce. So, you want to make sure they are getting enough veggies, even the ones they eat from your grass.

What Is Poisonous To Guinea Pigs?

There are certain outdoor plants that are poisonous to guinea pigs. And you want to make sure that you cavies aren’t anywhere near them if you take them outside to graze.

Here are some of the most common poisonous plants to guinea pigs:

  • Foxglove (Digitalis) can be very dangerous for your guinea pig if they ingest it. This is mainly because foxglove contains a poison called “digoxin” which in turn, can cause cardiac arrest. 
  • Similarly, oleander is also dangerous for guinea pigs. If ingested, this plant can cause cardiac arrest as well as gastrointestinal distress.
  • Baneberry (Actaea) contains a toxin known as “baneberry”. This in turn causes your guinea pig’s liver to shut down and their kidneys to fail.
  • Buttercups (Ranunculus) contain a toxin that can be very dangerous for your guinea pig to ingest. If they do, you may notice gastrointestinal distress and liver failure as well as respiratory insufficiency.
  • Yews (Taxus) is another plant that is poisonous to guinea pigs. If ingested, yew can cause heart failure and death.

At the end of the day, if you don’t know what it is, it’s best to keep it away from your guinea pigs.  Go with what’s familiar. 

Final Thoughts

So, you’re not sure if your guinea pigs can eat grass? I’m telling you that they can. And it would be a great addition to their regular diet. 

But the thing is, it’s up to YOU to make sure that the grass is safe for them!  

Chemicals on grass will make your guinea pig sick and contaminated grass sprinkled with animal urine will, too. Clean grass is a must, friend. 

Also, be careful about where you get the lawn clippings from! Damp grass should be avoided, too.  Only dry grass should be fed to your friends.  

Keep in mind that you should never use grass clippings that have been cut by a lawn mower.

The large blades of the mower will tear up the grass and with it all the dirt particles and chemicals from fertilizers or pesticides. This will not only contaminate your guinea pig’s food but also make them sick with things like bloat or poisoning.

Just remember: it still makes sense that hay is their main staple of food (after all, it’s readily available everywhere) but don’t forget about fresh grass every now and then for variety’s sake…it’ll help keep their teeth in good shape, too!

It might seem like a lot of work, but these are all just little precautions that you should take to keep your little piggies safe and healthy!

A balanced diet for a Guinea pig. (2019, July 29). FOUR PAWS International – Animal Welfare Organisation.

Beck, A. (2013). Guinea pigs: Keeping and caring for your pet. Enslow Pub.

Diet – Guinea pigs – Our pets. (n.d.). The Largest Animal Welfare Charity in the UK | RSPCA.

Guinea lynx :: Poisonous plants. (n.d.). Guinea Lynx :: A Medical and Care Guide for Your Guinea Pig.

Guinea pig care. (n.d.). Animal Humane Society.

Guinea pig health. (n.d.). Metropolitan Guinea Pig Rescue.

How to care for your pet Guinea pig » small animal hospital » college of veterinary medicine » University of Florida. (n.d.). Small Animal Hospital » College of Veterinary Medicine » University of Florida.

Poisonous Plants: Cornell University Department of animal science. (n.d.). Cornell University Department of Animal Science.

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