Question on lithophytes and lime

[Wynn Dee13]

Island Girl- People do add crushed oyster shell to their orchids. Read Ray's post above.

[King_of_orchid_growing:)]

Limestone rocks, dolomite, crushed egg shells powdered calcium, fertilizers with calcium, calcium citrate pills (yes, the ones you take as vitamins) - they all work. I'd be careful about the dosage with the calcium citrate pills though, they dissolve pretty quickly and is pretty bioavailable.


I would not try growing orchids that are naturally found on granite with calcareous rocks. Too risky. Granite usually has a slightly acidic pH.

[Chris Green]

Hi.

I do like my rupicolous Laelia's. I only have one right now but have grown a few. The species i have is Laelia fournieri and i grow in in limestone chunks, fine aquarium gravel and with a tiny layer of moss on top.

The rupicolous Laelia grow a little different to most other rock growing plants. They require very very high light levels in general to get flowers, basically full sun morning til night and they get most of their water from spending time in cloud cover, due to how high they grow up in the mountains in Brazil. Though a benefit of them being from such high altitudes is that they can take low temps.

[james mickelso]

In Vietnam there are paphs that grow only on limestone. Also Laelias grow in the gran sabana in Venesuala I think. I have grown lealias and BLC's on rock before and use lava rock as a potting media a lot. I have a couiple very nice vertically oriented lava bombs that I will plant some Catts and laelias on soon. Most epiphytes don't care what they are grown on as long as they get three squares a day.

[Chris Green]

Oh, i forgot to mention Epidendrum goodspeedianum Another favourite rock growing plant of mine and it can get a little bit big... canes can get up to around 7ft long

[Leisurely]

Stabilizing the plants on a rock could be easily accomplished by simply drilling a few small holes in the rock and inserting metal rods to which the plants can be secured by ties. A little sphagnum moss around the roots might be beneficial.

[blackvine]

Originally Posted by Ray

Be very careful with calcium additions.

Yes, some lithophytes grow on limestone, but they may not necessarily be ON the limestone, but in the detritus and leaf litter in the cracks in the limestone.

Such natural limestone deposits are very slow to dissolve, so while they do release the calcium into the root environment, it is a very low dosage, and doesn't boost the pH enough to overwhelm the acidity of decomposing vegetation. If you use a water-soluble additive, I think you'll be pushing it too far. You're much better off with a fertilizer containing the calcium and magnesium (they work better together) or top-dressing with slow-to-dissolve stuff like dolomite or crushed oyster shell.

Ray, does this apply to those with hard water supply? I'm in the Chicago suburbs and our water - I think - has all the minerals needed for orchids, including calcium and magnesium. I want to grow some of my orchids on rocks in a terrarium. Not a clue what these rocks are - they're just porous and pretty. I don't think I need to supplement with anything special, other than my weekly/weakly dose of regular orchid fert (from Hausermanns) . . . or, do I?

[Edward Brookes]

I have Dendrobium kingianum thriving on a weathered granite boulder. The plant is far healthier than the others of this type which I have as epiphytes on trees, in pots & teak baskets. I know this species is as tough as they come, but on the rock, it is way stronger than the others. Does anybody think dried, crushed eggshell would be benificial to orchids as a fertilizer, source of calcium or just an old wives' tale?

[blackvine]

Edward, old wives tales frequently turn out to be true. Yes, eggshells contain calcium and could be used as a top coat for calcium-needing plants. I know that just from gardening!

[kindrag23]

Originally Posted by blackvine

Edward, old wives tales frequently turn out to be true. Yes, eggshells contain calcium and could be used as a top coat for calcium-needing plants. I know that just from gardening!

Interesting I will have to remember this.

---------- Post added at 09:08 PM ---------- Previous post was at 09:03 PM ----------

Originally Posted by Chris Green

Oh, i forgot to mention Epidendrum goodspeedianum Another favourite rock growing plant of mine and it can get a little bit big... canes can get up to around 7ft long

Wow I love Epidendrum they are quickly becoming a favorite of mine, but I feel my bifalce and gramm. Wallissii will be taking up all my space.

Love this thread though very interesting information.