Using stone af only media?

[Brotherly Monkey]

Originally Posted by Erce

like medium pea gravel?
when you say ph neutral, i were thinking on cooking them in hotwater to stearilise them!

but my main concern is if the roots can grow in it? are they stones maybee to heavy for dendrobium roots?

sterilizng won't do much if the material itself is reactive, like limestone

[King_of_orchid_growing:)]

Some orchids should be grown in "rocks".

Some terrestrial orchids grow on a limestone bedrock with a little humus, topsoil, or leaf litter on top. Limestone is alkaline.

Others grow on a granite bedrock with leaf litter, humus, or topsoil on top. Granite is acidic.

There are even lithophytic orchids that grow smack on the limestone, granite, or whatever it is they're growing on in the wild.

Some terrestrials grow in a combination of humus and crushed basalt.

Others grow in straight up sand such as certain Satyrium spp.

There are terrestrials such as Epipactis helleborine that grow lushly in soil rich in serpentine.

Then there are those that grow in between rock crevices such as Spathoglottis plicata in which one of it's habitats is known to be like this.

It really depends on the kind you're talking about.

Lithophytic Laelias do exist, and they're commonly called rupicolous Laelias after the rupicolous fields they come from, which consists mainly of rocks and very short scrub.

Dendrobium kingianum is mostly found as a lithophyte growing on sandstone or granite.

Enc altissima grows on limestone.

The list goes on.

[Erce]

[QUOTE=King_of_orchid_growing;299999]
Dendrobium kingianum is mostly found as a lithophyte growing on sandstone or granite.
QUOTE]

The thing i wanted to try, is to pot a kinganium and a nobile dendrobium up in medium pea gravel? Is that a bad idea

[King_of_orchid_growing:)]

I'd try the Den. kingianum in the pea gravel. The Den nobile just grow that as a regular epiphyte.

The Den kingianum is in my opinion a better choice for this experiment.

If you want, you can also try Dockrilla striolata or Dockrilla linguiformis.

[Izzie]

What I'd be concerned about, is what stone the pea gravel is made of- as Philip brings up, would it be a stone that is reactive?

[Izzie]

What about aquarium gravel? You can get several sizes, a lot of it is sealed in some way. I have the natural kind in my humidity trays.

[Norton]

I grow one of my Den Phals in straight gravel. It works very well in my opinion. Funny I came across this today as I just repotted a few hours ago. The root growth was excellent. The roots had formed a large ball and had started coming out the drainage holes on the sides. If you look at your local pet store you can find nice natural looking gravel that will work just fine. Between the heavy gravel and the mass of roots my Den Phal has not required any staking or rhizome clips to stay upright, even with spikes full of blooms. I like to experiment some with cultural practices and this one really worked for me.

[Erce]

Originally Posted by Norton

I grow one of my Den Phals in straight gravel. It works very well in my opinion. Funny I came across this today as I just repotted a few hours ago. The root growth was excellent. The roots had formed a large ball and had started coming out the drainage holes on the sides. If you look at your local pet store you can find nice natural looking gravel that will work just fine. Between the heavy gravel and the mass of roots my Den Phal has not required any staking or rhizome clips to stay upright, even with spikes full of blooms. I like to experiment some with cultural practices and this one really worked for me.

Do you have any pic? i would love to see how you done it! And how often do you have to water?

[epiphyte78]

Most lithophytic/epiphytic orchids don't really care whether they are growing on rock or on bark. The main consideration is surface area...decrease the surface area (larger media) for better drainage and increase the surface area (smaller media) for more moisture. For example, really smooth bark has less surface area than rough bark. 7 medium sized rocks in a one gallon pot will provide less surface area than 50 smaller rocks in the same pot.

If you tend to over-water your orchids then you should decrease the surface area but if your orchids are usually dehydrated then increase the surface area. However, what I've found is that many of the epiphytic orchids that I grow respond well to less surface area and more frequent watering. Also, when you decrease the surface area you decrease the chance of rot.

Incidentally, SBOE uses 3/4" crushed granite gravel and they water the orchids potted in rocks twice a week for 25 minutes. They are a stone's throw from the ocean though so their conditions are a lot more moist than where I live around 20 miles inland.

[Norton]

Erce, I have no pics but can tell you my experience so far. I like to use gravel that is about the size of a pea. As I mentioned before you can find it in a pet store. They will carry several colors but I like the more natural shades of brown and off white mixed together. I use a clay pot and put a stone bigger than the drainage holes inside to keep the gravel from falling out. You could also use pieces of plastic mesh to block the holes. I water by placing the pot into a plastic container and filling it up to just below the base of the plant. Soak the roots for about ten minutes or so. Try to use the pseudobulbs as your indication for water frequency. When they are too wrinkled they need water. Good luck and remember you may have to adjust some things to suit your specific growing conditions.