What benefit is there to adding LECA to a bark mix?

[estación seca]

That the interface between two different media presenting a relative barrier to water passage has been recognized in horticulture and civil engineering for many decades. It was first explained to me by a civil engineer almost 30 years ago. Perhaps a shallow layer on the top of a container in a warm space would dry out rapidly.

[K-Sci]

Originally Posted by YetAnotherOrchidNut

I don't know where this myth comes from, no doubt it has some foundation, yet it doesn't make sense.

The idea comes from an over-generalization of priciples that apply for plants in soil. In soil, the particles are very small. They wash down to fill the spaces in the gravel. The result is a media that has less open space than soil alone because the media includes impermeable rock.
-Keith

[Shadeflower]

why are we talking about cactusses again?
This is Orchidboard not cactusboard.

Orchids are not grown in stones and soil. That's cactusses

We are talking about lecca and orchids. Lets be on the same page at least.

[Roberta]

Well, I grow my Rupiculous laelias in stones and a bit of soil...not an unreasonable way to grow a lithophyte. So it's not just cactus that grow that way.,

[K-Sci]

Originally Posted by Shadeflower

why are we talking about cactusses again?
This is Orchidboard not cactusboard.

Orchids are not grown in stones and soil. That's cactusses

We are talking about lecca and orchids. Lets be on the same page at least.

I though cactus were grown in sand and rock. Who mentioned cactusses? Or is that Cacti? Probably both.

-Keith

[SADE2020]

Originally Posted by estación seca

Layering potting soil over a layer of gravel for a standard house plant most definitely leads to worse drainage of the potting soil, not better.

Really?
All the soil packaging here instruct to first place gravel

[Shadeflower]

Originally Posted by Roberta

Well, I grow my Rupiculous laelias in stones and a bit of soil...not an unreasonable way to grow a lithophyte. So it's not just cactus that grow that way.,

I did not know you did this Roberta. I know they grow on rocks in nature but I know that neofinetia falcata does too.

I would never thought stones and soil would work even if they do grow on the stuff loosely in nature.

[Roberta]

Originally Posted by Shadeflower

I did not know you did this Roberta. I know they grow on rocks in nature but I know that neofinetia falcata does too.

I would never thought stones and soil would work even if they do grow on the stuff loosely in nature.

Yes. Learned the trick from an orchid club speaker who grows them very successfully, and it works. I start with a layer of gravel, then a very thin layer of sphag just to keep the soil in place. About 1 to 1-1/2 cm(half inch to an an inch) depending on pot size, of of potting soil (I like cactus mix) and the plant so that roots are in or just above the soil, then top it off with more gravel. Lithophytes may have some roots on rocks, but mostly they root down into the cracks where there is detritus and moisture, and some shade. This setup mimics that.

[K-Sci]

Originally Posted by SADE2020

Really?
All the soil packaging here instruct to first place gravel

Sade, I've heard that too. Speculating now. If the gravel is fine enough and the soil has enough humus, the soil may not wash down into the spaces.

BTW, I replied to you message re: my plants.

-Keith

[rbarata]

The techniques I use for rupiculous, that were taught to me by the best orchid specialist in Portugal (a lady in her 70's that owns more than 3000 orchids) are:

When using clay pots: a bottom layer of sphagnum and the rest is LECA or pieces of vulcanic rock. The sphagnum layer represents only 20 to 30% of the total height of the medium.

When using plastic pots: the order is reversed, i.e., sphagum at the top and the rest is just LECA.

In both cases, the plant roots grow in inorganic medium.

Heres an example of a Laelia vasconcelosiana that I posted a few days ago. It's growing using the clay pot technique.