Growing medium

Lee Poulsen
Thu, 12 Jul 2012 10:59:35 PDT
On Jul 12, 2012, at 9:28 AM, Chad Schroter wrote:
> Most of the components are fairly inert;  I have read that calcined clay (kitty litter, turface, drystall) has cation exchange properties, which apparently means it can store small amounts of nutrients (if present from added fertilizer), but other than that it seems to be personal preference ?

I don't think kitty litter, turface, and drystall are similar at all, at least the varieties of each that I've used. I would never use kitty litter in a mix because it's biggest property, that it clumps together into a hard ball when it gets wet, is exactly what I don't need to happen. Turface seems to be exactly as described: small bits of inert hard clay. But I have trouble finding it on a regular basis, and it isn't as cheap as other materials that are just as good (such as crushed scoria or lava rock). Drystall is just very small pumice; I use it in my seed starting mixes. But last time I went to get a bag from our local cactus/succulent nursery, they said it isn't available any more. Anyone know what happened?

--Lee Poulsen
Pasadena, California, USA - USDA Zone 10a
Latitude 34°N, Altitude 1150 ft/350 m

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