I've read in some bonsai forums that it's possible to use cat litter in alternative to the traditional bonsai soil, which is really expensive.

I want to try it in the potting mix I'm making for my interior plants. Does it really work? Has anyone tried this?

I was thinking maybe something in the following ratio:

Cat litter              50%
Perlite                 30%
Some organic (compost)  20%

I'm adding the perlite because cat litter is kind of heavy. Also, I'll be fertilizing it as needed.

The reason I'm willing to try it, it's because I tend to over water my plants, and I'm looking for a soil that will absorb some water, but will drain the excess, which seems to be the case for cat litter, otherwise bonsai growers wouldn't be using.

I know there are at least two types of cat litter.

There is a "clumping" type, which is made mostly of bentonite, and it clumps in the present of water, which is a great feature for the cat owner, but would be terrible for plants.

I'm talking about the regular absorbent kind of cat litter. The one I found is made mostly of sepiolite.


Sepiolite is a clay that's non-toxic (it's used in animal feed) but unlike vermiculite and perlite actually hurts, rather than helps, drainage. According to this source, it can absorb its weight in water. Unlike a hydrogel, it does not release the water back to the roots. This will leave your soil waterlogged, which will kill most houseplants.

Interestingly, sepiolite is very light, but your question (and my own experience) says that cat litter is heavy. This indicates to me that there are other components in cat litter that account for the increased weight. So, I looked into that...

According to this site (and others), non-clumping cat litter contains Fuller's earth, which is a heavy clay. According to the Encyclopedia Britannica Fuller's earth is a naturally occurring clay that is used to adsorb impurities from other materials. It turns to mud when wet, so, like sepiolite, not great for houseplant drainage. According to the Britannica, fuller's earth 'consists chiefly of hydrated aluminum silicates that contain metal ions such as magnesium, sodium, and calcium within their structure," which makes me wonder how the material would affect the fertility of the mix, especially the cation exchange complex.

Personlly, I would use a traditional bonsai mix, as i think that adding a ton of clay to the mix won't end well.


Additional sources on experiences with fuller's earth in pots:

  • It is good to soak up any liquid spills in the garage. Nov 1 '20 at 21:12
  • Jurp, thank you for your answer, but according to this video, it does not seem to be correct. The guy from the video is a bonsai grower and 50% of his soil mix is an absorbent clay which is 100% fuller's earth (at minute 4:40). And it does not turn into mud when wet at all. It absorbs water and nutrients in a way the plant can access. If the cat litter is made of the same materials, in theory it should work. Nov 4 '20 at 7:41
  • Well, obviously do what you'd like, but I was quoting industry sources and an encyclopedia, not anecdotal evidence. If you do use fuller's earth, then I'd recommend only using it on something you don't mind killing. This sounds a bit snarky, but is not meant to be - when I experiment with plants, I never do it with something I'd hate to lose. I know bonsai can be expensive. I have added additional negative experiences with fuller's earth into my answer.
    – Jurp
    Nov 4 '20 at 13:09
  • I love that you managed to mention cations in a post about cat litter.
    – csk
    Nov 4 '20 at 18:30

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