dehydration in lava rock and aliflor

[bethmarie]

I've got a lot of plants potted in lava and/or aliflor. I was cautioned when I got them that these mediums hold more water than people think, which may be true under greenhouse growing conditions, but in my conditions they seem to dry very rapidly. I've got a couple in 2 and 3" pots that have been set back significantly due to my under watering.
I grow indoors under lights, running about 50% humidity, with constant air movement.

I'm hoping to hear your experiences with these mediums, and tips from those of you who have plants thriving in one or the other.

Thanks!

[katrina]

What kind of orchids?

I grow under lights for at least 8 months of the year and my 2" and 3" pots have at least half sphag or they get too dried out. Even catts...sphag. Some of the seedlings in 2" pots are in sphag only in clay pots.

[bethmarie]

The catts, laelias and brassavolas are the ones looking dehydrated. But I've got a Phal or two & Dens in it as well.

I grow under LEDs, so some, but not a whole lot of drying heat generated there.

[AnonYMouse]

A majority of my plants are in inorganic media (LECA, lava, pumice, etc). The plants took sometime to adjust but came around.

I think the size of the media is important here. I use large pieces to take up space and smaller to retain water. The ratio differs with the kind of plants.

[isurus79]

I've always seen aliflor and lava rock added to make media more breathable and therefore dry out more quickly. I see it more often in very humid places like Florida or Houston, but not usually in a home environment.

[Leafmite]

This is my first year growing under T5HO lights. I have always previously grown in the window so I was surprised by the increased need for water.
I use straight LECA and red lava rock for my orchids except the Vanilla, Gongora, Sievekingia and mounted orchids. I combine these mediums with basket/net pots and plastic Vanda baskets. All of my pots and baskets are set in plastic containers or trays. When I water, I leave a little on the bottom for humidity (it is gone pretty quickly). If the orchids need more water, I soak them for a few minutes to give them time to absorb more water.

I hope this helps.

[My Green Pets]

I have Oncidiums in one inch pieces of lava and they are doing ok in it. I have some cattleyas in some smaller pieces of lava and they need to dry out completely between waterings or the roots will get nasty. If you are having trouble with it drying out too quickly, I can only recommend that you use smaller pieces.
My happiest cattleyas seem to be the mounted plants, as their roots dry quickly after watering.

[ALToronto]

All my lava rock dwellers are in clay pots and get watered every day. I use mostly big rocks. They're all on windowsills with some supplemental lighting.

[bethmarie]

Originally Posted by ALToronto

All my lava rock dwellers are in clay pots and get watered every day. I use mostly big rocks. They're all on windowsills with some supplemental lighting.

What genera do you have in lava, Al?

---------- Post added at 05:21 PM ---------- Previous post was at 05:16 PM ----------

Originally Posted by AnonYMouse

A majority of my plants are in inorganic media (LECA, lava, pumice, etc). The plants took sometime to adjust but came around.

I think the size of the media is important here. I use large pieces to take up space and smaller to retain water. The ratio differs with the kind of plants.

Most of mine came potted the same way, with large below and small on top. Are you growing indoors? Curious what plants you grow in lava/LECA and what your watering frequency looks like in these mediums.

[AussieVanda]

All my angraecum's are growing in a lava rock mix. It is mixed with charcoal and polystyrene. All my lava rock is 20mm in size. 3/4 inch?

I water heavily every morning, on hot days a second watering in the afternoon.

Edit: I should also add that I am using plastic slatted square vanda pots. Sizes used are 150mm and 200mm. (8 inch and 10inch?)