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?

Good question. I guess it can be read many ways.

My temps during the Winter challenge are 14c - 4c (54f - 40f), during this period I resort to a spray nozzle to trickle down the roots every 7 days and attempt to dry out the reservoir, having the leca constantly wet will kill the plants in short time.

My only real strategy in these conditions are to 'see them through' to the warmer weather and then re-establish the reservoir 1/4 from the bottom that gave such good results in Summer. I understood the wicking of this keeps the roots in constant moisture as the principal, which turns out to be the opposite of what I'm after in Winter.

With such cool temps (do you mean in your growing area or outside??) S/H may not be the best choice for your environment. It sounds to me that you are trying very hard to force the method to work in the winter, when ideally S/H reservoirs shouldn't dry out at all. I'm wondering if it wouldn't be better to go back to (and stay with) organic media, unless you buy heating mats for all.

Thanks I think you've answered my question. I wasn't sure if there was something I was missing but these temps look to be a limiting factor without a fleet of heating mats, any moisture is tricky let alone constant moisture.

The temps are reflective of the lowest in my sunroom (when raining), it does improve but have learnt to hope for the best but prepare for the worst. When it becomes 33c (91f) at night the s/h is a godsend though.

I read a good article on a Canadian growers experience (herebutnot blog) who encountered challenges in their cold. He also brought my attention to the aerial roots growing away from the media which I wondered about as became the case on many of mine.

Be careful relying on info from the herebutnot blog. He’s real good at making and sharing misinterpretations that become misinformation.

For example, aerial roots in phalaenopsis are not “growing away” from the medium. In fact, they are “reaching” for a place to grab and anchor the plant to provide mechanical stability. When I grew phals in S/H (I don’t any longer due to winters without a greenhouse), I often put them into pots having a diameter equal to-, or greater than their leaf spans. Those aerial roots soon grew into the medium, farther out from the plant, reminding me of guy wires on an antenna tower.

Fredmax, I grow all of my orchids in s/h. My summer temperatures are 30-40c and my winter temperatures sometimes are as low as 10-12c. I empty the reservoirs when the night temperatures drop to 16c and resume watering/flushing in Spring. I do give them a splash of water on sunny days (once or twice a month). So far so good, definitely not giving up s/h:)