On 11/02/2011 08:24 PM, stuart noble wrote:
On 02/11/2011 17:25, Emery Davis wrote:
Wondering if anyone has knowledge of this.

I bought a bag of smashed oyster shell chicken grit from the farmers
coop. Chicken grit has been recommended as a good way to increase
drainage for young maples in pots. (I also use sepiolite or other
mineral cat litter to hold water, oxygen and make rougher structure.)
But they may be talking about gravel, not shell.

I'm worried about increasing pH or getting too much calcium to the roots
as some of the mix is quite dusty, although most pieces are several
mills.

Am I worried for nothing? I potted up 10 good 2 liter palmatums as an
experiment, but actually I'd quite like to use the stuff and not have it
sit around for a year...

Thanks,

-E

I've used fullers earth cat litter in the garden and it behaves like any
other clay. Goes rock hard in summer so that water runs off it.

The best additive to improve structure, moisture retention, and oxygen
would be vermiculite IME. The coarse builders' grade will do if the
horticultural stuff isn't available at a reasonable price.

Cat litter is widely used by bonsai people, and if you get the right
sort is really an excellent (and very cheap) soil additive. I know a lot
of maple people who use it for container growing.

Personally my only objective with potting soil is to not drown a plant
before it can get to the next size or into the ground. But I started an
experiment in 2008 using the sepiolite litter with some Solanum which
have not been repotted since: it has not broken down at all an retains
water as well as when it came out of the bag. I've been using it in my
maple potting mix for a couple of years now with no negatives. So I
think you just tried the wrong stuff.

Vermiculite would be nice, but it's not widely available here and is too
expensive. Sepiolite costs around 0.25 EU/kg.

-E