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Plants in pots (outdoors)


Perusing the gardening questions I often see questions regarding what growing medium to use when planting in pots.

The following is my personal preference and I’ve had excellent results. I grow Bonsai therefore I’m mainly talking about trees and shrubs. Having said that, the following method is successful on many types of plants from cacti/succulents to woody plants and many types in between.

Firstly we need to clarify what a growing medium is;
It must support the plant, retain enough water to fulfil the plants requirements without waterlogging the medium. The growing medium must be able to carry feed/nutrients to the plant root system and also allow air to the roots.

Over the years I’ve tried many types of growing medium. Earth, mud, silver sand, builders sand, sharp sand, grit, coca husk type, varieties of bought composts, pea gravel, vermiculite, larger gravel, and various mixes of the above even hydroponic clay balls. I have to admit some were quite good … and some were pretty dire.

You see, the problem is that they all work… to some degree. The biggest problems are they are too wet/dry and/or soil compaction often seen as a loss of vigour in the plant.

Then one day, I was on a bonsai tree forum and saw someone mentioned ‘the open bonsai secret’. I was intrigued, curious and more than a little nosey.

Further research reveiled THE ANSWER.
Cat litter. Yup, you read right, cat litter. But not just any cat litter… Ho no! Not that paper or cardboard stuff. Not that wood pulp based stuff either. Nor any of that awful clumpy gubbins. No, no, no, no, no!

We’re talkin’ Fancy, Suave, Debonaire. Yea, dare I say it… Sophisticated. Verily the Rolls Royce of cat litters, the non clumping half baked clay granules. The one I use goes by the brand name ‘Sophisticat’ cat litter made from diamatomaceous earth (see below for more about this). You can get more inexpensive brands but I like this one because it has a more natural terracotta look when the litter is wet. Available at pet stores, supermarkets or online. price is about £10ish per sack (30 litres). For smaller quantities Tesco does a diamatomaceous earth cat litter for about £3:75ish per 10 litre sack, it’s their second most inexpensive stocked.

What is half baked non clumping cat litter?;
its a very absorbent porus irregular granules of clay that have been partially fired. This ensures the granules remain very absorbent, doesn’t clump (binding to themselves) and are more robust than none fired granules

How To Use Cat Litter;
Firstly, wear a dust mask then seive it through a small mesh screen (2-3mm) to remove the dust and very small granules. These fine granules make an excellent medium for taking cuttings. The dust can be used as a non chemical pest control (the microscopic dust particles are razor sharp which cut through insect exoskeleton, killing the beasties). Next, rinse the sifted litter until the water is clear. Now it’s ready to use.

Preparing the container;
Wash and disinfect the container. Using fine plastic mesh, cover the drainage holes with the mesh making sure it overlaps each hole by about 1/2" – 3/4" all around. This is to stop any litter from being lost. Fill the container to where the base of the roots are, then carefully pour cat litter around the roots and using a wooden BBQ skewer/chopstick/pencil push the litter amongst the roots making sure there are no air pockets. Top off with more litter to base of plant. Water well.

When to water;
Using a wooden BBQ skewer/chopstick/unpainted pencil push it deep into the cat litter. Leave it for 5 minutes. Pull it out and if its wet/damp don’t water. If it’s dry/barely damp then water it. When watering, water from the top. If you have done this correctly water will flow (not dribble) from the drain holes.

When to Feed;
This depends on the plant, however, having said that, you will need to feed more frequently as the cat litter is totally inert. On a personal note… I use liquid feed rather than solid or granular feed. I feel this ensures a more even distribution of feed throughout the container.

Benefits of using cat litter;
*relatively inexpensive
*odour free or pleasant light perfume scent (harmless to plants and humans)
*watering is easier
*feeding is easier
*easy to weed
*very little or no compaction
*looks attractive
*cats won’t use it as a toilet if its kept damp
*makes root pruning a lot easier (essential if the plant is to stay in the same container all its life
*some cat litters are made from diamatomaceous earth which consists of fossilized remains of diatoms, a type of hard-shelled algae and are used as a mechanical insecticide, pests don’t like to walk/crawl/slime/slither on it

Detriments of using cat litter;
*water using a spray or rose watering can or gently pour water or you may wash away the cat litter
*lightweight (tall plants/trees/shrubs will probably need support of some kind until the roots are well established)
*tall plants can be top heavy
*some trees/shrubs need a little plant matter so add well rotted pine bark
*If growing bog or high water demanding plants you will probably need to stand the pot in a drip tray containing enough water to reach the drain holes and checking regularly to ensure there is water for the plant.(having not grown bog or high water demanding plants this bullet point is just a guess)
I can’t think of any more.

Inexpensive alternatives to cat litter;
can’t afford or get cat litter where you are?
*finely broken terracotta unglazed plantpots
*finely broken brick
*fine shale (not as good as brick or terracotta)
*fine grit or gravel (poor but… if nothing else available)
*river gravel

A final point of note:
When bonsai books/demo’s talk about a bonsai growing medium, they’ll say ‘a free draining soil’. This means excess water FLOWS through the drainage holes in the pot, not seeps or dribbles through. Partical size of soils are larger than you think. Here we’re talking cat litter size granules.

Thank you all for taking the time to read this blog.
For more infomation please visit
Peace n Love,
StJ T.

Ians Insights Thoughts of a hopeless gardener.
#59. Rocks make good visual displays and you don’t need to water, feed or prune them.

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Cat litter contains urine.
Builder's sand is from the coast and contains salt. No good.

My Gerbil litter rots down in 3 months, makes more compost, with old potting soil, Horticultural Sand, Fish, blood and bone granules produces excellent results.
I am saving it in large bags under my greenhouse staging, it will be ready to use in April.
Bubble & Squeak busy chewing cardboard into tiny pieces even in the middle of winter. Cost miminal, just clear out the litter once a week and clean the inside of the old fish tank with a disinfectant wipe. Easy.

22 Jan, 2016


Half baked clay granule cat litter does NOT rot down. New cat litter contains NO urine (I didn't think anyone would be foolish enough to use used cat litter). The clue was in the part saying its slightly perfumed. Used cat litter is repugnant and foul smelling and doesn't cost £10ish per sack, but if you want your garden to smell like a council estate tower block stairwell, go ahead and use used cat litter ^_-

And yes, I did omit to say wash ALL sand, grit, gravel before using, but then again I did write the blog at 04:15.

Peace n love people ^_-

22 Jan, 2016


This is very interesting.
Could you expand on why your method is better than bought compost?

22 Jan, 2016


For the sake of this article I will be refering to soil, potting compost and organic growing mediums as 'soil'.

I wouldn't say my method is better just that I have had excellent results with this method.

Over the years I've noticed plants in pots do well for one to two years then they start to lose vigor, look weedy, tired and slowly die. Very often this is due to 'soil' being compacted and it doesn't take long for this to happen.
For a plant to grow well it needs 4 main things
Compacted 'soils' create problems such as water not penetrating the 'soil'. Water pooling on the surface and running between the inside of the pot and the compacted 'soil' (especially so with dry 'soil'). Feed cannot penetrate the 'soil'. Diluted liquid feed on dry 'soil' can damage roots. Soak 'soil' before feeding (this is so for any type of growing medium). Air cannot penetrate compacted soil.

All of the above stresses plants and leaves them suseptable to pests and diseases.

Half Baked non clumping clay cat litter are small irregular shaped granules that are very absorbent. The granules do not expand or contract are quite frost resistant with very little loss due to frost damage. Microscopically each granule absorbs moisture in its sponge like surface and structure and as each granule lies next to another it touches but also creates tiny air gaps and pathways. Cat litter is non toxic and inert, so no bugs or unwanted seeds in your mixture.

Cat litter offers the plants support (I have one tree that is 2' tall, 1" thick trunk and a canopy spread of about 2'. The round plastic pot is 18" diameter by 3 1/2" tall. Tree has been in there for 2 years and needed extra support for the first 3 months. Initially the root ball was reduced to 6" across and 2 1/2" deep so it was very top heavy, hence the extra support).
Watering is so easy using a watering can with a rose end.
The cat litter is so absorbent when you first wash it before use that you can hear it hiss as it soaks up water. Cat litter doesn't expand when wet nor does it contract when dry.
It only holds what it can and the rest FLOWS out of the drainage holes.
Diluted feeds easily reach all parts of the pot therefore the plant too.
The open structure of the cat litter allows plenty of air to circulate the roots.

One more thing folks, before anyone points it out, yes, I know this is hydroponics. But seriously if I'd titled this blog Hydroponic growing in your garden an awfuly lot of people would see the title and think, "Hydroponics...nah! too complicated for me".
Well let me tell you something. This blog is written by the worlds laziest gardener who always looks for the easy way and if I can do it so can you.

Peace n love ^_-

23 Jan, 2016


I mix my own I find the shop compost much to soggy when wet. I like your recipie and can see how it helps especially with drainage. Vermiculite in my mix is this years experiment usually use sand but it is sooo heavy. Love experimenting...

23 Jan, 2016


When I first heard about cat litter I was very sceptical, so much so that I waited 2 years before I tried it. Of course I used it on a sickley looking specimem that I was resigned to lose.
Three months later I had a healthy plant, lots of good fine roots, lots of new healthy growth. Now whenever I repot a bonsai I use cat litter.

Or there's this tale. One day while out at a restaurant I noticed a display of large Pine cones... so rummage rummage, prize, poke and got some. Four seeds from the largest cone. Months later I remembered the seeds, removed them from the fridge and planted two of them in damp cat litter. Months pass before I noticed two tiny seedlings poking through. 1 month later I gave them their first feed of Half strength liquid feed. They've been in the same pot for three years and will soon get their first root pruning. At present they stand about 6" tall.

They need more growth before I can correctly I.D. them. All I know is they are some kind of Pine. Stone Pine I think but not sure yet.

23 Jan, 2016


All this information should be passed to Bonsai Societies.

24 Jan, 2016


A lot of them already know, Diane, like I said, it's an open bonsai secret.

I've grown cacti and chillies as well as bonsai using cat litter as the only growing medium in the pot.

i've germinated various seeds and struck softwood, semi ripe, and hardwood cuttings in cat litter.

If anyone has large pots that they frequently move, they know how heavy they are. Using cat litter as a growing madium will reduce the weight of said pots by at least 1/3, especially if they wait until just before plant needs watering.

24 Jan, 2016


As an owner of cats that are spoilt and love life indoors through the winter, I do use a lot of catlitter, never would occur to me to try it for any of my plants/cacti, the only downside to this and yes I did learn the hardway is for goodness sake do not dispose of any spare or used catlitter on the garden,especially the expensive one that guarantees odourless, unless its an area put aside to train and encourage the cat to use one spot for them and leave the rest for you and your plants, these days some types are friendly to our gardens and made of eco friendly stuff, one can even add to ones compost, (obviously not without using the scoop to separate the nasty part first) many years ago I did a daft thing and emptied a littertray on the garden during one particularly bad winter, the binmen weren't getting around regularly and in those days we didn't have the huge wheelie bins, it was so good it literally sucked all the moisture out of the earth, I kid you not it took many years of adding homegrown compost to that area before I could successfully use that spot again...Very interesting blog StJohn, thankyou....

24 Jan, 2016


Thanks Lincslass, not having a cat myself I'd never thought about the downside of throwing out used litter with the nasties removed. But yeah, in hindsight I can see it would steal moisture from surrounding soil.
On a positive note, cat litter is also good for soaking up oil spills and chemical spills.
. . . And even blood (there's a handy tip for any homocidal axe wielding psychopaths out there).

1 Feb, 2016


What kind of feeding schedule do you use Stjohn? Clearly you'll have to start feeding before you would with commercial potting compost.

1 Feb, 2016


I was feeding once every two weeks, however in the last few days I've read some more interesting views from an expert about feeding (he uses the same growing medium as I) so I'm going to follow his advice.
Its easier if you visit his web page as the advice is quite extensive and very informative.

2 Feb, 2016

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