Trig it's supposed to also be good for mites and preventing diseases on slow growing cacti. Sounds like its worth a try. As I said a mate fo mine has used it for ages and loves it.

Yeah I've really been meaning to get some along with some replacement plastic for the greenhouse, will do so after Xmas. Pretty broke right now. Damn Xmas, nah it's pretty good because I know one of the pressies I will be getting is the Ariocarpus etcetera book

What size DE is recommended for cacti mixes HN, do you know? There are few sizes available.

Cheers.

I've been nosing around for ages for the sort of DE that is recommended, but I've had no luck down here. I used to use it in labs years ago for filtration - had no idea then that I'd have another use for it!

But oh, the idea that I could slice the blighters as they sneak under the surface of the soil...!

I'll keep looking I guess...

Trig,

As far as I know for insect control it must be the fine powder.

Does anyone know how many times it is possible to water a DE-treated pot before the DE becomes mixed in the general soil matrix to the point where its abrasive qualities are lost?

No idea, sounds interesting. I thought it was more the adsorption of lipids that killed the pests. I will have to read up on it a bit !!

I've always taken for granted that the abrasive properties were the primary method of inflicting death to exoskeletoned organisms.

Somewhere in my fused, rerouted, and generally overtaxed memory banks I recall a source that said that DE-silicas that do not have (or have lost) the sharp projections, grown by the original diatom organisms, are not nearly as effective in their lethal action.

Hmmm... definitely time for a defrag!