Pros and cons of lava rock - Page 3 - Orchid Board

cbuchman · #21 01-05-2013, 06:35 PM

I've found a lot of red dust washes off too. I've been using a big colander and running water through to get the dust off. I may try soaking next time as well just in case.

Nice basket!

Vanda lover · #22 01-05-2013, 06:51 PM

I soaked mine overnight, drained, rinsed and repeated a few times. There is still a little dust in the s/h containers, but it does no harm.

Ferns Daddy · #23 01-05-2013, 08:04 PM

I got a bag of lava rock today, the price wasn't that bad just a little over what I pay for orchid mix, I washed and made sure there was no dust in the last rinse the re potted a catt. in it I do like the looks of it, I'm thinking that I'll repot my others in it when they need to be repotted.
Thanks for all the great help, I now feel better about how I grow my orchids.

james mickelso · #24 01-05-2013, 11:58 PM

You can incorporate moss into a lava rock mix if you need more moisture.

RJSquirrel · #25 01-06-2013, 07:36 AM

this is really Rays topic. Hes an eye opener and considers all things. Your vanda will grow in nothing but a wooden basket. Like most orchids they will grow in next to nothing. Is why we put stuff like mix rocks moss etc etc on our orchids is bec we dont have a tropical climate thats moist wet or humid enough to sustain the aerial roots needs for moisture. Vandas be very water heavy plants. Planting the vandas in lava rock isnt going to make a bit of difference if you arent watering them enough. You can water them enough without the rocks is my point. Lava rock collects a lot of chlorides and salts in them tiny cracks. The tiny cracks will also collect a lot of water and restrict air movement across the roots. Think about it.

james mickelso · #26 01-06-2013, 09:14 AM

I used lava rock (cinders) for decades in growing bonsai and never had an issue with it collecting chlorides or salts. Because it absorbs water and then releases it slowly the water trapped in the pores of the rock is always readily leached out by the next watering. And because the rock has sharp angles and corners it never restricits the movement of air. If you put too much small moss in it that may clog the air spaces. But everything I have planted in lava is doing well. True the media is not really needed because most orchids can grow in no media at all but it does help to stabilize the plant and another nice thing about lava rock is that the roots don't seem to cling as tenaciously to it. I think that is partly due to the small void spaces in the rock itself. When I go to repot an orchid from lava rock, the roots are very healthy and the rock usually falls off the roots easily. But lava rock is heavy so when you do repot, you have to be careful when pulling the plant out of the pot. I just put the pot on it's side and gently pull the plant out. The rock usually falls away from the plant easily. What remains I leave. Rock is not for everyone. Give it a try in one plant and see if it is good for you. One other thing is that because the water adheres to the tiny cracks, the fertilizer is available longer just like in nature. But with the next watering it is leached away. Wednesday evening our orchid club had a great speaker from Gold Country Orchids here in California. He suggested that coral might be a good material for orchids to be grown in because a lot of orchids need calcium to grow well. Just a thought. Sorry I didn't get more info. I was busy trying to pick up on a new gal that just joined the club;->

ALToronto · #27 01-06-2013, 10:34 AM

Quote:

Originally Posted by RJSquirrel

this is really Rays topic. Hes an eye opener and considers all things. Your vanda will grow in nothing but a wooden basket. Like most orchids they will grow in next to nothing. Is why we put stuff like mix rocks moss etc etc on our orchids is bec we dont have a tropical climate thats moist wet or humid enough to sustain the aerial roots needs for moisture. Vandas be very water heavy plants. Planting the vandas in lava rock isnt going to make a bit of difference if you arent watering them enough. You can water them enough without the rocks is my point. Lava rock collects a lot of chlorides and salts in them tiny cracks. The tiny cracks will also collect a lot of water and restrict air movement across the roots. Think about it.

This vanda WAS growing in nothing in my home for over 3 months, and it was not doing well. It has dropped 5 lower leaves since I got it. The humidity in my house is 60-70%, which is pretty good for a house in Canada in winter. But not enough. That's why it is now in a basket with lava rock, charcoal, some coconut husk chips and a bit of sphagnum in the slats, keeping the charcoal from falling out. I hope it does well, otherwise the next step is a vase.

Vanda lover · #28 01-06-2013, 10:35 AM

I agree with you, James.
The idea of coral sounds interesting. I was wondering about the possibility of using it. I had a box of bird gravel on hand and since it contains calcium, I added it to my cymbidium mix. They grew well, but they might have anyway.

james mickelso · #29 01-06-2013, 11:43 AM

I think for the calcium to be readily available the pH of the water has to be around 4.5 to 5.5. If Ray is listening, please chime in as this is your expertise. But it may slowly leach out with each watering. I wasn't listening very well. And no I didn't get a date. (dang it. She is cute)

james mickelso · #30 01-06-2013, 11:46 AM

One thing I learned awhile back is that vandas need maximum light levels. They need all the light they can get. Here in SoCal most grow them outside in full sun. If not enough light they lose leaves and slowly die back. I think light is more important than water. I would think in the northern areas the winter would be really hard on them but the summers they would really take off due to the greater length of daylight. Anyone know if this is true?