Letting the pot/reservoir go dry

[Ellen H]

Hi All,

I've been growing in s/h for a couple years now. One question niggling at me is about those orchids (specifically my Catts and Dendrobiums) that like to get wet and then quickly dry. For those of you who grow these successfully in s/h, do you flush your pots and then let them go almost dry before flushing/fertilizing again? I often wonder if I should wait until the reservoir level goes low...or until I see only condensation on the interior wall of the pot....or no visible moisture at all? Or does it matter?

Which segues into...that cold dry winter rest for the Dens. Do you Den growers let your pots go dry in Winter?

Thanks!

[estación seca]

I wish I had time to water my Catts in S/H every day. I'm sure they would grow faster with roots constantly moist but well aerated. I try never to let reservoirs run dry.

[Salixx]

I water my catts at the same time as the masdevallia. I too wish I could water every day. Most of my catts have taken to s/h like a fish to water. I try to avoid letting them dry out.

It's my understanding that you can still water during rest periods, just do not fertilize. Or, you can do a more traditional rest.

[Ray]

If you routinely let them dry out, you're not growing in S/H culture, but in traditional culture, using LECA as the medium.

When you move a plant into any new, different root zone environment, it will have to grow new roots that are optimal for those new conditions. Once grown, they don't change. If your plants grows roots while constantly moist, they'll be fine.

Salixx is correct, a "dry winter rest" is more about no food than it is no water. For plants needing such a spell, either continue to water them, but with no nutrients, or let them dry, whichever you prefer.

[Ellen H]

Ok, thank you all for clearing that up. I do let my reservoirs go about half empty before flushing. The Catts really love this method of growing. Phals too, they get regular flushing and the roots are filling the pot and all over the place outside of it.

The Dens....the jury is still out. Many of mine need that cold, dry winter rest and I didn't get many of them cold enough last winter, so got no blooms. But cold + wet + light didn't make sense to me either, since cold wet roots are supposed to mean death to the plant. It's so confusing sometimes.

[hydroguy]

I grow with hydroponics and I think it is necessary to have a dry period between waterings on many types of orchids - including cattleya and dendrobium. These plants experience a dry season in nature so why wouldn't you want to mimic that in your growing area?
I use a hydroponic system that has an outer pot, inner pot, and water gauge - with LECA pebbles as the growing medium. The two pot system gives me complete control over watering and I introduce a dry period between waterings on many plants.
My plants also enjoy the rhythms of the seasons - more water during the active growing season (sometimes 2-3 times more!) and less water during resting (even totally dry for several days).
Being able to control the wet/dry cycle during transplanting (the transition from soil roots to water roots) is also a major benefit with this system.

[Ray]

I'm going to have to throw out a bit of disagreement. Maybe a few quibbles.

For many of the tropical orchids out there, the "dry season" is when it rains for for "only" a few hours a day, rather than the 18+ it might otherwise experience.

Even for those that do see days at a time that are rain-free, the humidity is often quite high, and the accumulated detritus the plants' roots are in stays pretty moist.

Besides, I have yet to find a plant that MUST have a truly dry period. Truly food-free, sure.

[hydroguy]

I don't know - I've seen many orchids thriving in the Everglades (including phalaenopsis clinging to trees) where it doesn't rain for days - sometimes even weeks - in the winter.
Have to agree about humidity though. But even so, humidity levels drop to 50% -or lower - in winter.

[estación seca]

If you try growing South African winter-rainfall succulents you'll meet plants that definitely require water-free summers.

[Ellen H]

For Dendrobiums that require the dry-cool-bright winter rest, how do you manage these in s/h? Mine will stay outside into the 40's or so this winter to chill them before I bring them in, but if I keep water in the reservoir the roots will be wet and cold. Problem?

I understand I could just let the pot go dry, but that is not truly s/h.