The very best perlite in the United States of America for use in a growth medium, is the perlite sold by Paramount Perlite Company, Paramount, California. Size 2/3 Perlite. - Millet

I transplanted two trees today, a Myrtle Leaf orange and a Thomasville Citrangequat, using a new experimental potting medium. 1 part of the blend (4 parts CHC 1-peat), and 1 part Paramount's 1/2-inch size perlite. This brand of perlite has no fines, all granules are approximately 1/2-inch in size. The CHC/peat is partially degraded as it is already 2 years old. I am currently noticing some problems with the traditional 4-parts CHC 1-part peat blend that is now 4 years old. As with most all blends it has degraded to the point where a lot of the Chip texture is turning into a meal texture. This requires a VERY CAREFUL watering to avoid any root damage, causing death to the trees. Therefore, I have added the 1/2-inch perlite as a 50 percent ingredient. Now all that remains is to keep records of the tree's response. - Millet

Philip, most "retail" perlite commonly sold has a mixed texture of perhaps 1/4-inch size as the largest, down to a point where a lot of fines, and even some dust makes up rather large portion of the product. This I think can cause a problem. Paramount's perlite (Paramount California) is a very clean 1/2-inch product. I will watch the blend for the next month or two, and report back. I have for a long time been on a quest to find the all perfect EVER LASTING medium for container citrus. I have come to the point, that I think the "perfect" medium might not exist. - Millet

Millet,

Please do keep us posted on what you discover as this is an area I am greatly interested in myself.

My oldest CHC filled container citrus is just at two years old now and is still holding up well, but from my experience under Florida growing conditions I have come to the belief there is NO organic potting medium that is going to last forever. Sooner or later our long months of heat and humidity is going to turn it all to mush no matter how rot resistant. The CHCs you turned me onto several years ago are the best I've found, but I'm expecting three to four years at best before I have to replace them.

Of course the trees are going to have to be root pruned ever two to three years anyway so I'll end up replacing a fair part of the media when I do, but still I'd like something that doesn't have to be replaced so much.

Have you looked at Turface or any of the other synthetic potting media components? I don't have any experience with them yet, but it seems a number of other perennial container plant growers use it or something like it as part of their potting media makeup.

.....Alan.

Do you know of any retailers who carry this Paramount perlite, or do they sell direct?

The bulk bags of perlite I've found at Home Depot and OSH (here in California) are made by "Therm-O-Rock", is very fine and has lots of small particles.

Alan, I have no experience with Turface, nor do I know anything about the product. I should look into it. Do you know a brand name for the product? - Millet

Turface is a brand name - http://www.turface.com/lawn_garden/index.cfm?lp=gb - but I have no personal experience with it. Only what I've read in other places. I've only recently started thinking about this myself.

.....Alan.

I don't remember the name of the product, but my mother used to sell a porous rock that was used for growing houseplants---it was basically a hydroponics system. The system was basically just these porous rocks and a float in a tube that went to the bottom of the container. All you had to do was maintain a water level that was between 0 and 1/4 of the depth of the container. She sold the components (the float tube, fertilizer and the rocks) the rocks were about a dollar a pound retail, and it worked well--we had all kinds of plants in the system including Norfolk Island Pine and Ficus. Later my mother found out from her supplier that basically the same rocks were used for making lightweight concrete. I went to my local concrete supplier and bought a pickup truck load for $20. The rocks are made by flash baking wet clay chunks-- the moisture in the rocks swells as the water turns to steam and then leaves a porous lightweight rock.

I have a few of the rocks still around the house and I have used them in my citrus containers, but only as a small part of the 4:1 pine bark mix. I have not tried a 4:1 rock/peat mix but it might be worth a try, however, while the do retain some water, they will probably need more frequent watering than the pine bark mix.

Skeet, you are talking about crude perlite in the rock form. - Millet

http://www.schundler.com/transit-mix.htm

They use Diatomaceous earth at the race track to absorb oil off the track after a crash. It is also use for cock roach control, because of the abrasive surface when the "rock" is crushed to a powder. Diatomaceous earth is a soft rock and crushes easily. Ascoria (lava rock) would be similar but much harder. - Millet

I would like to see a picture, However, crude perlite is not necessarily white and is not soft. - Millet