Perlite and water absorption

[PalmatierMeg]

I add extra perlite to my palm potting mix to make it less dense and freer-draining. I had always assumed that perlite did not absorb any water, rather let excess water pass through. Last weekend at a tropical plant sale in Naples I talked to a palm vendor I had bought from before. When I mentioned perlite he said that it did absorb water and I had to be careful with it (please don't sidetrack me with praises of pumice - no nursery here sells it and even a tiny bit of it from far away is prohibitively expensive). And I hate vermiculate.

So, do I need to be worried that perlite also may cause root problems with palms? Does it absorb enough water that I need to worry? This palm seller suggested I look for something called "Mite-e-Lite" or something like that. It's also expensive but I may be able to find it in FL to use on a particularly rare or sensitive palms. He also mentioned lava rock, but not the red rock found in garden centers - it's full of iron. Only black lava rock will do. I've never seen black lava rock in FL, except in palms I get from Floribunda.

Let's discuss. I'm sure I'm not the only person here that needs more info.

[rick]

Im not sure if it really absorbs that much water, especially compared to most of the other things added to potting soil mixes. I had a large bag of perlite that got soaked after Tropical Storm Isaac moved through last year. The bag was still very light but you could definitely tell the perlite was holding some water. Trying to scoop up wet perlite its about like wet sand but perlite will dry out faster. From my understanding vermiculite holds more water than perlite.

Not sure whats available in your area but Bushel Stop around here carries Mite lite in red or black. I got a bag of red to make a really porous mix for bromeliads. To me it looks like small red lava rock. The pieces are about penny or dime size. I think it seems a bit too chunky to use for a palm potting mix but I would be interested to hear if anyone has tried it.

[Perito]

The lava rock holds water also, probably more so than perlite.

[kahili]

Perlite doesn't absorb water-thats the key thing. What it does is holds water (for a short time) in the various little crevices and cups in it. When the soil (or soiless) mix starts to dry out, it will absorb any moisture from what the perlite is has in its "cups". Doesn't take long. I always have some amt of perlite in any bedding mix for containers and always add extra amts to the mix for palms, plumerias etc.

[Turtile]

As long as there is adequate oxygen in the potting medium, you'll be fine. Anything with fine particles that will further break down over time such as peat can lead to problems. Pine bark is a great alternative since it takes a long time to break down, holds little water and particle shape allows for a large amount of oxygen. (Make sure you don't mix it with your mix though! The fine particles will fill all of the space - just use bark and lime!)

[KennyRE317]

Perlite doesn't absorb water-thats the key thing. What it does is holds water (for a short time) in the various little crevices and cups in it. When the soil (or soiless) mix starts to dry out, it will absorb any moisture from what the perlite is has in its "cups". Doesn't take long. I always have some amt of perlite in any bedding mix for containers and always add extra amts to the mix for palms, plumerias etc.

this is what i came in to say