Potting in lava rock

[james mickelso]

My apple trees lasted two years and then dried up during the summer when I couldn't get up there to water. I have a well and can't get up there as much as I used to. The remaining apple tree awoke for it's third year but split with a late frost and couldn't survive after that. So i just plant cedar and spruce with some ponderosa thrown in the mix each fall before the snow hits.

[nutgirl]

Originally Posted by james mickelso

So i just plant cedar and spruce with some ponderosa thrown in the mix each fall before the snow hits.

Probably wise since conditions can change pretty fast up there. If you're not there all the time, best to go with the natives.

One of my favorite places.

Maureen

[NYCorchidman]

Originally Posted by james mickelso

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.

Oh, I see. It has a new lead looking good. a nice rescure plant on the way to recovery successfully I guess.

[NYCorchidman]

Originally Posted by tucker85

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

I think it will be excellent in your climate as the air is very humid already. you don't really risk rotting them by frequent watering. I love watering my plants

[NYCorchidman]

Originally Posted by nutgirl

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

That sounds like a grea idea! I never really wanted to hang those large baskets with roots hung down all over, plus the drying issue.
Maybe I should try vanda in lava rock

[NYCorchidman]

Originally Posted by nutgirl

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

Good luck and let us know how it goes!

[NYCorchidman]

Originally Posted by james mickelso

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.

I was going to respond to Cym lady's post but you already have.
Thank you!

I actually moved my dendrobiums from lava rock to bark mix. As whiteRabbit points out, I find lava rock get slightly crushed everytime I move the pot and see tons of fine rock powder. a little bit annoying, but the fast draining&drying is the best quality it offers I think.

Miniature dendrobiums stay in the lava rock as they don't seem to wobble much at all.

By the way, do you soak the entire pot in a bucket of water to wash out the salts once a month or will heavy watering do?

[james mickelso]

The rock I use is very hard. It isn't like a pumice so doesn't crush at all. It has been rained on for about 660,000 yrs so has little dust left. I get it off an old volcano east of the sierra eastern Cal. I dip all of my orchids when I water (the crowd gasps), because I couldn't afford to water all of them with the RO or distilled that I use. Since most of mine are rescues anyway, most share some sort of bacterial or fungal affliction. But since I don't get the leaves wet, it doesn't spread very much. The new growth you see here is all I am after. The current growth is immaterial to the final objective which is to get flowers. Here is what some of the flowers look like until I can get good fairly defect free plants. This BLC has some sort of bacterial defect in it which distorts the flower and gives it the brown edges. It could be viral but it is getting better as each pbulb flowers. It used to be a frankenstein flower. This happens to be blc greenwich elmhurst. I run water from my yard hose once in awhile to wash out any accumulated salts. The rock has myriad holes of various sizes in it but is not porous throughout. It holds moisture for awhile yet is not wet like say an average bark. It just aids in keeping the micro environment humid around the roots and leaves. Unlike bark or moss and especially peat which stays wet in the middle, the lava rock dries evenly throughout. I also burn holes in the plastic pots for increased airflow around the roots. I try to mimic the natural environment the orchids grow in.

[keithrs]

I'll jump in and back up cymlady.... Lava will hold onto salts over time if you don't flush the media well with RO water on high TDS water/fertilizer mixtures. If you flush you'll be fine. I use crushed rock for catts.... I find it to be a bit cheaper than lava and just as good. I was using Leca but it cost way more for the same results.

[james mickelso]

Hi keith, yes crushed rock is a good substitute for most any media. It is superb in not allowing water to sit and cause problems. The two-three yr old orchids I buy at SBOE use granite as media. The roots like it. They can water whole benches full of seedlings in 2" pots at one time. The lava rock I use isn't porous enough to hold onto salts very much. Large holes that are not connected so the rock doesn't soak up water the way sponge rock or some cinders do. But I still wash the pots every once in awhile. My water out of the yard hose has about 350 ppm salts in it mainly calcium carbonate and manganese. So I started using store bought RO and distilled. I add NPK and minor minerals to it. Really cut down on nitrate burn and other problems. Some day I'll break down and get an RO system. 45 gal barrel and shutoff float. Install a small pump and water each separately. Keith is leca a porous rock? I have some very finely porous rock the size of gravel in some of my rescue catt pots that is very light, porous, and hard. I was wondering if it is the same.