S/H and cold winters
 

Semi hydro was a big success for me last summer, I switched alot of struggling plants into leca cups with holes 1/4 from the bottom, they mostly showed immediate improvement (the Tolumnia hated it).

I had reservations though knowing in 30c temps it would be great but with no evaporation during the 13c days in Winter may not be so great having a constant pool of water.

My suspicions were correct and had to move most s/h plants back to bark in Winter or stop watering altogether mitigating risk rot or fungus problems. My Psychopsis thriving in summer and initiating new growths turned yellow and shrivelled (assuming it was root rot), but Catts and Phals seem to stick it through with occasional sprays only.

Has anyone with cooler winters mastered semi hydro? I could see clear benefits in dry warmer weather but don't want to seasonally repot to save them in the cold, or learn by losing more plants that s/h is suited to specific climates only. Thanks.

buy some seedling heating pads - easy peasy. this will keep the root temps up to a reasonable range.

I'll certainly experiment with a heat mat, it might mean a limited pool of plants as may be difficult at scale.

Moving back and forth from semi-hydro to bark is a recipe for disaster. Pick one and stick with it. The roots acclimate to the media, and you can't just flip-flop back and forth.

If you're going to leave outside, 13C is too cool for SH for many genus of orchids. So bring them inside for winter if you're leaving in LECA.

WW is right. If the plant grew the necessary roots once changed to S/H culture, they will be no good in bark, so will fail. Roots grown in bark are no good if put into S/H and will fail.

Pick one that works best you you overall, and stick with it.

S/H would only be appropriate outdoors in cool winters for cool-growing plants. The warm growers would need to come inside.

All s/h plants came inside to 18c lows, the issue was the highs stay at 18c during the day and no higher than 20-21c so the reservoir didn't move (like the 30's which all the s/h plants thrived in). The reservoir sat there for weeks and the algae turned the roots green/black, spreading to or dehydrating the plants.

For the experienced and successful growers what is the temperature range are you growing at?

As is, that question cannot be answered, because there are too many OTHER variables that have to be taken into account.

I know Asian cymbidium growers whose plants get snow in winter.

Phalaenopsis should never - in my opinion - be allowed to see below 70F, if you want them to grow well. If the ambient humidity is very high, maybe 60.

I don't understand the reservoir not moving. Aren't you flushing them at least once or twice a week regardless of level of water in reservoir? I flush minimum of once a week. I try to keep the reservoir at top level of holes regardless. Sounds like you're not watering often enough.

Average growing temps for me, for everything except cymbidiums, I shoot for 65F to 75F in winter months, and temps in summer months run 70F to 100F. Humidity 60% to 90+% depending on time of year.

It's a balance of numerous things whether growing in bark or semi-hydro. You have to find the right balance of all in your conditions. Algae is just from having a clear container+moisture+light and shouldn't effect the growing.

---------- Post added at 08:23 AM ---------- Previous post was at 08:21 AM ----------

I just re-read your first post. Having a reservoir hole 1/4" from the bottom of the pot isn't growing semi-hydro. It's more like growing in an inorganic medium, and requires watering a lot more often than semi-hydro.

Is the reservoir 1/4 of the way from the bottom to the top or 1/4" deep?