Red Lava Rock

[Ray]

I avoid lava rock for s/h (which is a passive hydroponics technique - no pumps or controls) because it traps and holds minerals really well, mandating relatively frequent replacement.

I have used it for "traditional" culture - I just released a bunch of new plants grown in it - but do a lot of flushing with plain water.

How fast it dries is related to the size used (finer=slower) and your conditions. It is used a great deal in Hawaii, where the conditions favor it, and it is cheap and plentiful.

[Bird Song Farm]

Originally Posted by Cookiemonster

Would you mind explaining passive hydro please?

Secondly if you would like to use this medium well not in SH but as a mixture of other components- how fast does this stuff dry?

Appears as though Ray took care of your questions. If not, PM me.........

Al

[Lorraine]

Originally Posted by DelawareJim

Lorraine and Kip;

I'm curious, when you say sort into small, medium, and large, is that approximately nickle, dime, and quarter size; or less that 1/4 inch, 1/4 - 1/2 inch, and larger than 1/2 inch; or do you just divide a bag into the smallest 1/3, medium 1/3, and largest 1/3?

Cheers.
Jim

I get the red lava rock, wash & divide the bag from the box store into the sizes. They are all usable in different sizes of pots. There is always a lot of crumbles and red dusty stuff on the bottom of the bag that is useless to me.
I will check out the landscape rocks. I tried to find some "feather rock" for a large pot, A BIG basket of dendros was given to me to play with. Will look for some there too. Thanks for the suggestion Jim.

[Royal]

I like using a few big chunks as a replacement for styro peanuts in the bottom of the pot for those that need a bit more bottom weight or stability. That's about it.

Ray, Thanks for the tip regarding flushing this stuff.

[DelawareJim]

Originally Posted by RoyalOrchids

I like using a few big chunks as a replacement for styro peanuts in the bottom of the pot for those that need a bit more bottom weight or stability. That's about it.

Ray, Thanks for the tip regarding flushing this stuff.

I’ll have to give the big chunks in the bottom of the pot a try. I've got a Dendro. 'Emma White' that's getting so tall it's getting top-heavy. It's in one of Ray's 5.5 inch S/H pots and since the roots are down into the bottom of the pot, I can't go with Ray's squat pot.

Last time I was at Al's Orchid Greenhouse in Leesburg, VA I saw that he has all his S/H Dendros in 6 and 8 inch clay azalea pots for stability. His are on a gravel floor and get watered 2-3 times a day. Unfortunately I don't have that luxury.

Cheers.
Jim

[jim blanford]

I have 12 tons of black lava rock in the beds around our house as mulch, it's great never have to replace it I think it's better then wood mulch. I haven't used for my orchids yet but I just might. How's this for a lava rock.... Jim

[DelawareJim]

Jim;

I think that was the idea Lorraine had using an orchid instead of a petunia.

Jim

[Ray]

If Al is watering several times a day, he's probably growing traditionally in LECA, not using S/H culture.

I have no first-hand knowledge of this, but I have read that the chemical differences between lava sources can play a huge role in orchid-growing success, so it's probably a good idea to do some experimentation before going large-scale.

[peeweelovesbooks]

Well, I grow all my catts in straight black lava rock. They are doing very, very well. Having said that, I have to water constantly. I had thought about switching to moss, but after much evaluation, I have decided to stick to the method that works for me. It's relatively cheap, but it's a pain in the butt to clean. I have to soak the rocks for about a week or two and rinse, rinse, and rinse.

[Cookiemonster]

maria why do you keep soaking the lava rock? I dont get it, please explain-