Lava?

[Stone]

In my quest to find the perfect substrate rollhappy I'm trying 100% lava rock (scoria) with some species. Has anyone tried it long-term? How did you go?

 

[wjs2nd]

I have some catts in lava. I find it a little hard at times with watering. Sometime they need watered every day other time I can go a few days without watering. The one I have in bark (division of the same plant) is doing better. I'm probably going to switch the others into bark soon.

 

[Cochlopetalum]

I grow cochlohybrids in it sins 2007 and I have only had to repot some of them ones.
I also have Dendrobium eximium, Dendrochilum glumaceum and a couple of other things in it for several years.
It's essential to get rid of the dusty and smal stuff, so I always put it tru a siv.
Sorry about my bad english.

 

[Ozpaph]

I grow cochlohybrids in it sins 2007 and I have only had to repot some of them ones.
I also have Dendrobium eximium, Dendrochilum glumaceum and a couple of other things in it for several years.
It's essential to get rid of the dusty and smal stuff, so I always put it tru a siv.
Sorry about my bad english.

Hey, I understood every word even if your spelling was phonetic. Don't apologise we appreciate your input.

 

[mrhappyrotter]

With the right conditions and attention to detail, I think you could make just about any substrate or media work for slippers long-term. So, the perfect substrate for you, may not be the perfect one for me and vice versa.

Anyway, I've not personally grown slippers in lava rock, but I've seen a good number of acquaintances and nurseries test it out on them, never with much long term success. In every case, they've switched to another substrate except in those cases where the plants deteriorated to the point of no return or died before they could be switched out.

The general consensus was that it was too difficult to water the slippers as regularly and consistently as they needed in an inert media like lava rock. It would work fairly well for phrags left sitting in saucers, but then they'll grow in just about any inert media when sitting in saucers of water.

 

[Rick]

I've never tried 100%, maybe 25% with roths and tigrinums mixed with either bark or chc.

I wouldn't say it got me anywhere special.

Seems like I've seen some cactus growers us it.

Some say the quality of the lava varies a lot with location/color (red vs black)

Most of the info I originally got on lava use came from the tropical fish hobby. Since it is so porous, it can be a great substrate in trickle filters (maximum surface area for bacterial colonization). But some said that some types contained too much toxic metal while other sources were just fine.

 

[Secundino]

I use it, for rocklaelia (flava, milleri, etc) and Psychopsis; for Cattleya 50%:bark, same ratio for Oncidium-group and Phal. Great for plant that need getting dry inbetween. Only fine lava for my seedlings in compots - but repotted as usual every six month in new lava. Just clean und wash it as cochlo said, if it fits to your watering schedule, it will work.
Depending from where the lava comes, it can contain high amounts of iron.
Big plus: after washing and drying/sun-drying, you use the same media again as it does not break down. Great aeration. It never rots. And it looks good. Caution with salt built-ups.
But consider that it is heavy.

 

[Stone]

The reason I thought that this might be worth a try was when I noticed some orchids (various) which were placed on a tray of 5mm scoria sent their roots into it for quite a distance and when lifted, brought up lots of the stone with them so they obviously enjoyed growing in it (or on it).
The problem of underwatering could surley be solved by including some finer material. (I can get hold of all sizes here easily from dust all the way up to 40mm) It should be just a matter of tweeking to get the mix right.
So anyway, so far I've put in 2 bellatulums, 1 hangianum, 2 vietnamense, 1 wenshanese, and 1 niveum in 50mm pots with 5mm VR. And 1 wenshanense,
1 concolor and 1 henryanum in 75mm pots in 15mm VR. I think feeding at every watering is probably important. Keeping my fert EC to 0.3 dS/m and flushing well every 2 waterings/feedings. They seem to be drying out about
Here's one bloke that seems happy with it:
http://roseg4art.com/Growing-tips/growing_paphiopedilums_in_lava_r.html

http://roseg4art.com/Growing-tips/growing-phalaenopsis-in-lava-rock.htm

 

[NYEric]

Plants from the Orchid Zone have some kind of lava product as a media. I have not seen it anywhere on the East Coast USA. I am using a product called Featherlight (or something) from Black Jungle Terrairum supply, It's a spun glass product and is very light. I use it as it is not moisture retentive.

 

[gonewild]

With lava you don't really know what minerals it is made up of since it is a random mixture. It may contain toxic amounts of certain chemicals that may have some effect on plants. Maybe or maybe not the point is lava is not like leca in that it in a known mineral and then "baked".
Lava may leach out undesirable minerals.
If you use lava as a media you will not be able to know exactly what nutrients your plants are actually getting.

 

[gonewild]

With lava you don't really know what minerals it is made up of since it is a random mixture. It may contain toxic amounts of certain chemicals that may have some effect on plants. Maybe or maybe not the point is lava is not like leca in that it in a known mineral and then "baked".
Lava may leach out undesirable minerals.
If you use lava as a media you will not be able to know exactly what nutrients your plants are actually getting.

What? That's kind of crazy, but I agree it is a possible problem. I have grown plants in lava and it works OK but not near as well as leca. If I lived where I could get free lava I would use it foe stuff like cats and phals but not paphs.

 

[Secundino]

Commonly it's not 'fresh' lava you get. The lava you can buy has been washed by rain for a few hundred/thousand of years... And you don't now either what is leached out when you use bark.
If you want absolute control of the media and the chemicals, you must use an 100% inert material.

 

[gonewild]

Commonly it's not 'fresh' lava you get. The lava you can buy has been washed by rain for a few hundred/thousand of years... And you don't now either what is leached out when you use bark.
If you want absolute control of the media and the chemicals, you must use an 100% inert material.

With bark you know the chemicals leaching out are from once living plant organic tissue that is fairly consistent within a species of (tree) bark..
Lava could have content of any mineral and that varies from source to source. Lava may not necessarily have been exposed to rain as it may be mined from below the surface.

 

[Secundino]

OK, we are speaking of different things. I meant lava (ashes) aka lapilli. I don't believe the mineral content is easily washed out. It's even used in freshwater aquarium.
Most plants love to push their roots into it.

 

[gonewild]

I think we are talking about the same "rock". I'm not saying it is not good to grow plants in.
I have used it in the past but it is not the "perfect" media because for a media to be perfect we need to know what it is made of.
Lava by itself just did not work perfectly as a media and is certainly not an improvement over lighter weight Leca minerals.

 

[Stone]

The lava here is very ancient (gazillions of years old) It has almost 0 CEC and almost 0 buffer capacity. Some samples (unweathered) have a rather high pH
(7-9) but this is easily brought down with a good wash. Once the dust is gone the pH stabalizes to whatever you want. The 15 to 20mm size looks very old and has lost most of its red colour which I presume is some kind of Iron compound. Its VERY porous and some pieces even float. It is often used in commercial hydroponic set ups and doesn't leach anything. Theoretically all you need to do is monitor your solution pH and EC. For a $100 I can get a truckload so I figure its worth a try.

 

[Rick]

Despite potential source issues, it get used ( or used to get used a lot) for aquarium filtration. That would have provided a more sensitive test than plants.

I would suggest (depending on how long you want to kill on this project)leave a bunch of this lava soaking in your water of choice, out in the sun. If you get algae growing in it (or mosquitoes breeding in it), it's probably not leaching anything bad.

Kind of reminds me of an old Aborigine or Native American line that if you don't see anything swimming in the water, it's probably too toxic to drink.:wink:

However, ( due to chlorine) non of the test animals at work can handle the tap water for much more than 1 hour!

 

[Stone]

I would suggest (depending on how long you want to kill on this project)leave a bunch of this lava soaking in your water of choice, out in the sun. If you get algae growing in it (or mosquitoes breeding in it), it's probably not leaching anything bad.

Thats a very good tip:clap:

 

[gonewild]

Despite potential source issues, it get used ( or used to get used a lot) for aquarium filtration. That would have provided a more sensitive test than plants.

Not really. Fish tolerate and appreciate salty water much better than orchids.

The lava as potting media is going to accumulate salts from the irrigation water and fro evaporation within the air holes. Sooner or late this will become an issue unless a huge amount of water is applied frequently. Growers in Hawaii use lava to grow a lot of species but they get a lot of water also.

History lesson......Lava was tried decades ago, it is not unknown and if it was a great media for orchids we would never have used bark.

How much Potassium leaches from lava?

 

[Stone]

History lesson......Lava was tried decades ago, it is not unknown and if it was a great media for orchids we would never have used bark.

Decades ago they didn't have the nutrient data available now. As I said It is used commercially for hydroponics so it DOES work. You just need to get the watereing and feeding right.(which may not be so easy?)

How much Potassium leaches from lava?

TONS!!