Cat Grass Drainage, What You Need to Know

archie cat-eating grass proper plant pot
  • Use a proper plant pot with holes at the bottom.
  • If your pot does not have holes at the bottom, only lightly water the soil, so the water starts at the top and slowly falls to the bottom of the pot.
  • Use soil that drains easily.
  • Soak the seeds before you start, so don’t have to overwater it later.

In 2015 I started growing grass for my cat Archie. When I started at first, it was hard not to give up, it kept on going wrong, and so many batches failed to grow to produce usable results.

It took me three months to get it decent and for it to be consistently okay each time.

Each time I grow more, I learn more. The batches get better and better; denser, more luscious, long-lasting and healthier.

During that time, my roommate tried and failed, and his girlfriend did well but was having the same learning curve that I had.

One of the first things I discovered is that proper drainage is essential when growing cat grass.


The Basics of Cat Grass Drainage

When you add water to your cat grass, the water should drain away, so the soil is very gently damp. There should be no standing water.

Watering the grass once per day is perfect, this means it gets as much water as possible, but not so much that it could go moldy.

If there is standing water or the soil becomes waterlogged, the grass will get moldy, and the roots will rot. Sadly if this happens, it is best to throw the grass away.

Grassroots also need oxygen, and if they are flooded in the water they can’t get any.

This article shows how to get the correct drainage in your cat grass.


What to Do If Your Cat Grass Kit Pot Has No Drainage Holes

When people grow regular pot plants for themselves, they make sure the pot is deep enough for the roots to flourish, and has good drainage, which goes into a tray below the pot.

However, loads of cat grass kits have very shallow pots with no drainage.

So you have to put less water in, so the bottom of the pot stays dry and it drains down to the bottom. However, there is not enough for it to collect there.

cat grass dry bottom

In this picture, you can see the top of the soil is moist, and the soil at the bottom of the pot is dry. The wet soil is a darker color than the dry.

You do this by putting less water in, enough to cover the top of the soil and go down a tiny bit, but not enough to get to the bottom of the pot.

This means the water does not drown the roots, as it can drain down to the bottom of the pot to below the roots.

When watering the grass, you need to make sure no water goes down to the bottom of the pot, as then there is no space at the bottom of the pot, for the water to drain down to.

If you look underneath, you can see the roots and there’s no water there.

cat grass underneath


If You Overwater and There Are No Drainage Holes

It’s easy to overwater the grass. If there are no drainage holes, I take the grass with the soil out of the pot, turn it upside down, shake it around a bit, so the excess water comes off.

cat grass upside down shake out water

If the seeds have not sprouted much yet, it’s very hard, because there are no roots to hold the soil together when you take the grass and soil out.


Why Do Most Cat Grass Kits Not Have Any Drainage

Cat grass kits are quick, cheap, and convenient.

When the grass has grown, so the grass is about 7 inches high, the roots crowd out the pot, and the grass starts to get less green, succulent and tasty. You throw it all away and use the next pre-made pot in the kit.

It’s a bit like ordering a delivery pizza, or a ready-made microwave meal; it’s quick, easy, more expensive in the long run and maybe not as good as a homemade one.

They also have good instructions and branding, which makes them tempting to use.

As I will show you, investing in a proper plant pot is the best way to go.


Investing in a Proper Pot with Drainage If You Are Going to Be Growing Cat Grass for the Long Term

plant pot holes at bottom

A deep pot with drainage that you would use for growing normal household post plants is best. Check it has decent holes at the bottom and a tray for the water to go out into.

It’s better because:

  • You save money in the long because you can reuse the pot, with a cat grass kit you use a new one each time.
  • You can buy the soil separately in a larger bag, so each batch of cat grass is cheaper to do.
  • The grass lasts a lot longer, so you don’t have to grow new grass as often. With a cat grass kit, you have to grow fresh grass around every ten days; with a proper plant pot, it can last for a month or six weeks. This is because once the roots have filled a pot, the grass starts to lose its color and vitality. A larger plant pot takes longer to get filled with the grassroots

People often only invest in a proper plant pot to grow grass, once they feel more confident as they have done it so many times with a cat grass kit. Also, once they are sure their cat likes grass and so they will grow it regularly.

I recommend going straight for the proper pot the first time because the drainage and results are so much better.

The shallow pots in cat grass kits mean the grass is lower down, so the cat does not have to bend over so much to eat it, but from what I have seen, cats don’t care if the pot is a bit higher because it’s deeper.


Soil with Good Drainage

High nutrient soil can be really tightly packed, so the water does not drain through it well enough.

Some cat grass kits have the pots already filled with soil made of larger fragments that you lay the grass seeds on.  Soil made out of larger pieces drains much more quickly.

On top of the grass seeds, you lay about a third of an inch of high nutrient soil on top of the seeds which comes in a separate packet.

This means once the water has gotten to the seeds, it can quickly drain away.

I found that ordinary plant soil that comes in the large bags works fine, and has the drainage needed.

You need to make sure it does not have any pesticides or fertilizers added to it as they can be dangerous for your cat.


Signs Your Cat Grass Has a Drainage Problem

grass mold


Flickr, noricum, Snow Mold

When you add water to your cat grass, the soil should stay only gently damp to the touch, as most of the excess water has drained away. There should be no standing water or visible water sitting by itself.

When I had too much water in my cat grass, after a couple of days, it got moldy.

This is a picture of the same kind of mold on a standard lawn. It is like very think white wisps of hair, almost like a light amount of cotton wool.

Sadly with cat grass, there is nothing you can do. It’s too detailed and fine to get out, and not good for your cat.

If you have a cat grass kit, then throw that pot of grass out into the bin.

If you have your own plant pot, wash it properly to get rid of any mold or spores, then use it to grow another batch of grass.


Soak the Seeds Before You Start, so You Don’t Overwater Them

soaking seeds

As much as having good drainage in your cat grass is essential, even with good drainage, you can’t overwater it. Especially with a cat grass kit where there is not drainage holes at the bottom of the pot.

Some people miss out on the step of soaking the grass seeds before planting them. It all seems too much work and they think maybe they can miss it out. ‘

‘Water is water, and why not let the seeds get it in the soil.’

Sadly it doesn’t work that way…

Then their cat grass does not grow, and they compensate by putting even more water in it. This causes waterlogged soil where the roots cannot get oxygen, and they rot.

This picture shows how to do it.

  • Leave them in the shallow water for 8-12 hour, no more
  • Place them in the amount of water they need to soak up, maybe a bit more, but not a lot more.

Then you can put them in the soil, with no need to overwater them. So you aren’t tempted to overtake advantage of any drainage in the soil.


The Mistake Beginners Make with Cat Grass Drainage

I have found the problem I had is the same that most other people who fail at making good cat grass have as well.

When I first started, I presumed using a cat grass kit was the way to go. The instructions were like having my handheld and it all seemed specially done for the purpose.

The main problem with many of them is the shallow pots don’t have holes in the bottom to drain water out of them. They are also small, so the grassroots quickly fill them, and you have to start again with a new one.

I found other people who have tried growing grass using cat grass kits and failed. It was all because they could not get the water to drain correctly because the pots did not have holes at the bottom

However, once I realized Archie likes cat grass, and I was going to continue doing it, I decided to buy proper plant stuff.

Every batch worked, none of them failed. The grass also lasts much longer because it took longer for the roots to fill the pot.


Writer: Ian Taylor

ian taylor archie cat