Potting in lava rock - Orchid Board

james mickelso · #1 05-21-2012, 12:07 AM

I'm a fan of potting in lava rock and here are some of mine. It holds moisture well and yet has lots of air flow preventing root rot. I can water nearly every day when it gets hot or the catts are growing quickly.Phals seem to like it very much. It is reusable and I get it for free when I go packing in the mnts up north. I sort it through various size screens and just bag it up.

NYCorchidman · #2 05-21-2012, 04:19 AM

I have two dendrobium hybrids potted in lava rock. They do well in it as they are free draining and I can water everyday.

I didn't know you can grow phals in lava rock. I always thought it might be a little too dry for phals. I guess not. are you using lava rock only or mix with something else?

Your cattleya looks quite dry though with lots of wrinkles on the pbs unless it is something usual for that plant.

james mickelso · #3 05-21-2012, 10:12 AM

Yes the leaves are dry. This is another rescue orchid and so I couldn't overwater since there was little root material, I potted in this lava rock so it would dry out as fast as it could. No rot.

tucker85 · #4 05-21-2012, 10:47 AM

I think lava rock is an excellent potting medium. A fast drying medium that requires frequent watering is ideal for many orchids.

nutgirl · #5 05-21-2012, 11:06 AM

I put my Vandas in it and they are doing quite well.
It's too dry here for bareroot but lava rock in wood baskets gives them just the right amount of moisture and air.

Maureen

Leafmite · #6 05-21-2012, 01:25 PM

I use Lava rock for everthing except jewel orchids and the mounted orchids. Works great and I don't have to disturb my orchids with yearly repotting.

Cym Ladye · #7 05-21-2012, 01:30 PM

All lava rock is not the same and a lot depends on the TDS level of your water. I would avoid lava rock in any ratio for Cyms as many forms accumulate salts after 2 years and become toxic to the roots on contact.

CL

WhiteRabbit · #8 05-21-2012, 03:13 PM

I'm always wondering about lava rock so appreciate the comments here. I've had a couple Catt alliance do well in straight pumice, but when they get bigger, it's too much hassle to sift so much of it to get out all the dust and tiny bits.

james mickelso · #9 05-21-2012, 08:50 PM

The lava rock I use is very pH neutral and has a range of pore sizes. I have a couple catts that are on their 3rd or 4th year in the same pot and seem to be doing ok. One of the things I like about it is that I can water heavily and wash out any accumulated salts. The pots dry quickly no matter what. LM I am impressed that you can grow orchids in Chico. I have property in McCloud by Mt Shasta and it is as dry as Aridzona or so it seems. And hot July-Sept. Cym, if you wash the pot once a month the salts wash out. But there is some lava rock/cinder that has a high pH of 9 or more. That isn't too good for most orchids. I soaked my first batches of cinder years ago when I potted all of my huge bonsai collection in this cinder. It's neutral pH works well for me. One of the drawbacks as Sonya knows is the weight of the pot when you use it for larger pots. I don't. And unpotting an orchid needs care because the lava rock is heavy and will pull on and break some roots when you get it out of the pot. But for rescues and smaller orchids it works for me. And I put it in the bottom of all my pots instead of foam peanuts so that there is some weight. That way the pots don't tip over with longer leaved varieties.

nutgirl · #10 05-21-2012, 08:59 PM

You're right, this is not an orchid friendly environment. I have a GH for summer (misters and swamp cooler). Max temp 95-100, RH 45% if I'm lucky.
If they can't adapt I don't grow them.

I'm experimenting with Cyms outdoors under a tree to see if they can take the dry heat. Daily water.

Maureen