Diatomite in S/H

[phragguy]

Hi All
I have move some of my phrags into pure diatomite using the S/H technic.
I read on a site that this forms to much alegea and the rock lays against itself so the roots can not breath right.
Has anyony used this by itself?
any advise would be helpful.
Thanks
Russell

[littlefrog]

It is what I use... I don't think the algae is a problem, and there is plenty of air space in the pot.

I often top the pot with just a little bit of good sphagnum moss, which cuts down a bit on the algae growth and looks nice.

[phragguy]

Thanks littlefrog,I usally have all my phrags in moss but thought I would try S/H. I did top dress it with moss. Just can't leave the moss along.
Thanks
Russell

[Ray]

Joe DiDimenico sent me some diatomite when he first started imporint it and I tried it under my greenhouse conditions.

It was horrible - the light color favored the algae growth, and it was way too compact, so the root suffocation quotient was maxed out. However...

I have since realized that I might have been able to do better with a coarser grade than I tried.

I have been quite successful with it as a non-s/h medium, and would guess it's pretty good in growing conditions that cannot manage the RH too well.

[ScottMcC]

there is a brief article in this month's Orchids magazine about diatomite and mineral retention. Essentially the conclusion is that it will pick up various water soluble salts and retain them within the media despite thorough flushing, and the only way to get rid of them is to do repeated prolonged soaks. This may necessitate unpotting and changing to fresh media while the soaking is going on though.

[IdahoOrchid]

Originally Posted by ScottMcC

there is a brief article in this month's Orchids magazine about diatomite and mineral retention. Essentially the conclusion is that it will pick up various water soluble salts and retain them within the media despite thorough flushing, and the only way to get rid of them is to do repeated prolonged soaks. This may necessitate unpotting and changing to fresh media while the soaking is going on though.

That is interesting since there is a product out there that uses the larger sized diatomite as one of its main ingredients and it is advertised as being reuseable a number of times. The product is Aussie Gold.

[Ray]

Don't believe everything you read, Steven.

The Aussie Gold folks are good at marketing, but in my mind, any medium that contains organic components is definitely NOT reusable, and Dr. Wang's article on mineral retention also speaks volumes about reality.

[Diatomite Joe]

Hi to all,

I would like to respond to some of the questions/comments regarding diatomite and Aussie-Gold.

First, I would like to say that I have avoided commenting for some time on the various orchid forums because I would rather not get into arguments with other growers regarding growing mediums as results are highly variable in my opinion and rarely the mediums' fault when things do not go well. That being said, I will only talk about my experiences with diatomite and Aussie-Gold.
I have been growing with diatomite for over 4 1/2 years in a variety of ways. I grow phrags on a flow table with the pots in 1"-2" of water in straight fine diatomite. I have no algae in my pots and the phrags are growing like weeds. I repot yearly. I have only had algae 'problems' is in smaller S/H containers when growing under lights. In non S/H growing, I use a variety of combinations of diatomite, CHC, coir, perlite to suit my many different orchids.
As far as the mineral issue, I think that people have over reacted to Dr. Wangs' article in that most growers change their medium yearly or at most up to 2 years. While the diatomite will absorb the minerals and retain some of them, most of the excessive minerals will remain within the medium and not adversely effect the plant. I have catts in the same diatomite over 2+ years without any negative effect.
On the Aussie-Gold topic, I agree with Ray that any mix which is using organic components is not 'reuseable' in the normal sense, but the coir is very slow to break down and I have plants in it well over a year that are doing fine.
Quite honestly, I don't reuse my mixes but rather put them into the compost pile and add them to my outdoor gardens in the spring. The extra fine and fine diatomite are a great soil conditioner which will retain moisture in sandy soils and help break up heavy clay soils.
I use the larger diatomite as a base for drainage under my cyps and they are doing great.
I realize that some may think that I am shilling for my products (another reason why I don't normally post), my response to that is try it first before you dismiss it. If it doesn't work well for you, move on and do something different. I get far more positive responses than negative ones.
One last note about diatomite; it is the only natural source of proven 'plant available' silca that I am aware of currently available.
Finally, I would be happy to share a photo or two if you are interested in how well my phrags do in S/H, just email me.

Good growing,

Joe DiDomenico

[kielley]

Hi, I've just joined this community after searching this site on a few occaisions. I'm going to jump right in and say that I switched most of my plants- mostly cattleyas- into aussie gold last year with great results. I did this because many of my orchids had gotten dehydrated by the dry hot summer here in northern California and by vacation neglect. The diatomite did a great job of rejuvenating the whole collection. I have some concerns about salts accummulating, so I flush the pots frequently. I'm growing the catts in net pots; a few phals in clear plastic. I no longer worry much about too dry or too wet. Just everything else. Which is why I joined this group.
Thanks for all your input!

[IdahoOrchid]

I think it is probably the coconut husk that contributed most to the rehydration. The diatomite is mostly in there for drainage assistance.