Using Perlite for the first time

[Suresh Kalyanpur]

I have not heard of any one using Perlite in their mix for growing orchids because it is not available here in India.

My perception has been that Perlite comes as granules, about 1/2 to 3/4 cm in size (please correct me if I am wrong) and is to be mixed with the other ingredients as a part of the potting mix.

Very recently I came across an Advert that there was someone supplyng Perlite here in India. I wrote to them and within a couple of days the parcel arrived. To my utter surprise I found that it contained a coarse mix of Perlite slightly larger than grains of sand. Is this how it comes?

My question now is as follows: I generally use charcoal, tile and brick pieces for most of my orchids in clay pots with holes at the bottom and on the sides as well for better air circulation and good water drainage. How do i add the Perlite to this sort of mix? Would it not get washed away every time I water the orchids?

[katrina]

It does come in this very small size. I typically use the larger/coarser perlite when I'm mixing in w/chunkier mediums for my orchids.

I use this small particle size in w/my terrestrial mixes...specifically w/my tropicals, cacti, and any outdoor potted plants.

You can still use the smaller particles...it will help to keep the medium open to some degree but you're right in thinking that some of it will eventually wash out of the pots.

Hope that helps.

[Fiona]

I use perlite when I need to improve drainage or aerate a bark/peat-type of potting mixture, depending on what will be growing in it. From what I have read it is some sort of volcanic rock which has been heated, and then pops into the little bits. Be careful when working with it, it is very important to wet it before using it, as it gives off a lot of dust, which irritates the lungs.

[Undergrounder]

That is very small for what i normally use, i use a 'extra coarse grade' which is about 3/4cm as you say, about the size of peas.

I grow just about everything in it, 100% coarse perlite. But you can add it as a mix to other mediums as well.

I've never used that fine stuff you're talking about, i think there's a difference between 'horticultural perlite' for aerating soil, and 'building' or 'hydroponic' perlite which is bigger, and used in making light concrete, insulation and in hydroponics.

I wouldn't use it in a charcoal/brick mix, because it would probably wash out... but in a mix with sphagnum moss and/or peat it's sometimes used.

[Orchid126]

The small perlite, rather than opening the mix, would actually fill in the tiny air spaces and make the mix less aerated. The roots wouldn't get the air they need. The larger perlite is better. Check out this article at First Ray's site under "Free Info" about particle packing:

https://www.firstrays.com/cgi/cart/commerce.cgi