“Extended Moisture” Mounting

Epiphytes, for the most part, live attached to trees and shrubs, or with their roots in the moss growing on the surf of-, or in crevices between rocks. Many will tell you that mounting is “the best way” to grow plants, but I can tell you from personal experience that unless your growing conditions favor that method – high humidity and frequent watering – doing so can be an issue.

Why? Because mounts tend to dry out really fast. Even if you put a pad of moss over the roots, it will eventually break down and crumble away. Well… here’s a way to extend the time the mount stays moist – lightweight expanded clay aggregate – LECA!

What??? How can you use “marbles” on a mount? Easy – by gluing the pellets to it!

In this case, I use a cedar slab (sold for grilling salmon), smeared some fast-set epoxy on the surface, then poured some dry LECA onto it. It is important to use “fast-set” epoxy (I used 5-minute stuff) so that the liquid does not soak into the pellets, which would preclude absorption.

The LECA provides great texture for roots to hold onto, and will hold water for a lot longer period of time than will a plain slab.

As of this writing (16 January 2020) I haven’t tried it, but that’ll be coming in the spring. I have, on the other hand, conducted a crude experiment to see if this really does have a “moisture extending: benefit, and it does!

I took the bone-dry mount pictured above, weighed it, then completely immersed it in a bucket of water for 10 seconds, figuring that might be typical of a brief hosing-down of a mounted plant. After shaking off excess drops, I weighed it again and did so periodically after that. The room where I hung it was 60°-61°F and 75% RH, with no air movement. Here’s what I saw:

Weight Loss of LECA Slab
HoursGramsRetained
Dry352-
038230
138028
437220
637018
163608
183586
243564

Weight (grams) versus Time (hours)

So you can see that the LECA held water for quite a while. I didn’t have a plain slab to use as a comparison, but the uncoated back was totally dry within 2-3 hours at those conditions.

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