Using Diatomite as potting medium
 

Hi guys and girls, I really need to know urgently if anybody has used diatomite as a potting medium or as part of a potting medium and whether it was successful or not.

For those who do not know, diatomite is an totally organic medium which originated by one celled diatoms collecting silica as they grew and then fossilized over time. Today diatomite is mined and used in various industries.

You get fresh water or sea water diatomite. I am interested only in fresh water diatomite. Please help!!

Thanks

Dont believe everything you hear about diatomite.
 

A popular commercial potting mix containing diatomite reports orchids can never be overwatered. I have over one hundred cattlyeas, oncidiums, and dendrobiums which nearly lost all of their roots due to prolonged dampness and inevitable rot. The rock appears to store large quantities of water. This supplies continued moisture to orchid roots, but also to any organic material contained in the mix. I propose the continued overall wetness of the material was the problem. When used alone diatomite might be o.k. I would experiment with a small number of plants at first. Try potting these in clear plastic pots so you can keep an eye on the root system. Remember orchids might appear to be well for some time when root rot occurs. Then suddenly all portions of the plant rapidly declines.
:goodluck:

Diatomite sounds like it's pure lime. I'd be extremely cautious about ensuring proper pH in the pot. Also I'd investigate whether the concentrated calcium would be appropriate.

I have put some phrags, paphs, phals and catasetums in straight diatomite for over a year now, so far so good.

I use about 1/3 to 1/4 Diatomite in most of my mixes (different sizes, depending on the mix) and have had no problems with it. I would be a little uneasy about using only Diatomite for potting, but some (like Jorch, above) say it works.

Ed

Beanluc, diatomite is calcined freshwater diatomaceous earth mud, so it is essentially 100% SiO2.

H&R uses it as an additive to their seedling mix, but it stays way too wet for my growing environment.

Likewise, the claim that a commercial mix made with it "cannot be overwatered" is hogwash.

It is prone to algae growth ontop of the potting medium, phrags love it when potted in a SH setup and it does well for me as a 50% blend medium sized diatomite and 50% medium sized CHC.
Comparable to perlite in what it does, however it is heavier and will not break into smaller pieces unless you really grind it.

Hi, thanks for all the replies on diatomite. It will really help me!

Hi,
What does diatomite provide to plants that other media does not provide? Is it not just silica based rock that maintains some predetermine amount of water? Is it heavy to ship? Have been wondering what the attraction to this one is.
Orchids3

I've put 3 "Cats" in diatomite using clay pots a couple of years ago as a test. I have yet to see any difference between them and any others that are in bark.