Pot sizes for regular potting using LECA

[bogdan]

Hello
I read that bigger pots can be used for s/h potted orchids, due to the nature of the particles that wick moisture uniformly.
My question is, would this apply to using LECA instead of bark in regular pots, or that would keep humidity longer, thus rotting the roots (of Cattleya alliance plants in this case)?

I did pot some plants directly in 6" pots from being overgrown in 3" pots and used Hydroton (I imagine this would be a no-no-no with bark). I did not plan to use s/h on these, as I wanted to see if they can grow without a reservoir as well, and to see how fast they would dry. If the need arrises, I may put a bigger saucer under them and call it a reservoir.

Thank you!

[Ray]

With any medium, the drying is always from the top surface and along the pot wall, in toward the center.

"Staying moist" has never rotted an orchid root. "Suffocation" has.

When you change into a different root environment, you will experience root loss. Don't make the mistake of equating that with "moist", rather than "different".

LECA offers the advantage of being able to absorb and wick really well, which "sucks" the water out of the spaces between particles, leaving them open of air flow, so roots don't suffocate.

However that absorption capability is a double-edged sword. In the S/H environment, where the LECA will (should) stay constantly wet, it's not a problem, but in traditional culture, allowing the LECA to dry out between watering, mineral and waste buildup will be accelerated.

[bogdan]

Thank you. So what you are saying is that more salts will deposit on the surface, therefore increasing the need to flush the pot more often. If this is the only issue, I don't necessarily see it as one.

[Ray]

First - my apology for not answering your original question about pot side - I think overpotting is far less of an issue with LECA than most other media types.

As to the mineral deposits, unfortunately, it's not just an "on the surface" phenomenon. Consider this scenario:

• You water regularly with a fertilizer solution.
• The LECA pellet becomes saturated with that solution.
• As it dries out, it does so from the outside in, with precipitation of the fertilizer solids as it does. Left to become totally dry, there will be solids all the way to the center.
• Re-dissolving of a precipitate is not as rapid as making the original solution, so when you water it again - with the liquid again penetrating from the outside in - all of the deposits do not redissolve. The stuff at the surface has a greater chance than does the stuff in the interior.
• Over time, you will see deposits at the surface , but it will be throughout the pellets.

The same is true of bark, but it simply doesn't absorb as well, so tends to decompose before the buildup is an issue (unless you are really bad about repotting).

All that said, I like LECA as a potting medium for more traditional culture. You simple need to be aware of the possibilities and account for them.