Dialing-in an UHL grow chamber

Gadzooks

Supporter
I recently completed a 7cu ft chest freezer conversion into a UHL grow chamber and wanted to get some tips from those of you that have successfully grown RHH and N. Villosa. Ranges of temperatures, hours for the temperature cycles, light-hours, average RH, and anything else you can think of. Additionally, a list of plants that would live together under these conditions couldn't hurt either.
 

Gadzooks

Supporter
Well, I should at least give you a primer on the current configuration. I modeled it based on a video from our friend Brad and an article authored by Dr. Jeff Shafer. I am using a PetsPioneer temperature and humidity controller. Which provides 3 device controlled surge protector. The light is on one of the controlled receptacles and provides the heat input in addition to the 12hr grow period from 0800-2000. The humidity is controlled via a 25CFM fan that turns on at 70% and turns off at 80%RH. The freezer is cycled to maintain day-time temperatures at 70-72F and night-time at 40-43F. The light fixture is a common hardware-store RBW 32w LED growlight. I added some mass in the form of a sphagnum propogating tray and some freezer packs (not shown) to arrest changes in temperature from one state to the other. The freezer is much better at sinking heat and so the drop from one range to the other occurs in 1hr. Anyone got tried and true graphs of relationships of temperature, humidity, and light cycles? If so, I'd love to benefit from your experience.
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Gadzooks

Supporter
Soo it's been a few weeks. I've been reading quite a bit. Looks like a 30F swing is sufficient for all UHLers and that it's the drop not the temperature that is significant. Additionally, a UHL grow chamber is not needed for young plants. I have one so I intend to use it to figure out what works.

During all the research and trials, I flipped the spectrum to blue-white at 53.3µmol/s and expertly scorched all the tips on the HI sphagnum. I have been propogating it from an orchid stowaway for the past year.
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I removed half the sphag and placed back where it was happiest and the rest on the bottom of the chamber. I flipped the spectrum to red-white at 44.9µmol/s
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Also, for some reason my temps where out of spec low. So I moved the band up because I was getting subzero indications on the sensor. I also set up the fan to blow straight onto the sphagnum in the bottom of the freezer. As a result, humidity quickly picks up when below the setpoint. The temp rise is solely the LED light fixture's contribution over ambient temperature and seems to plateau around 75F. Fan only really kicks on during the cool-down as the humidity plummets. You can see the cycles during the night.
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Concerns going forward are:
Is my light too close? It's 8-Inch from the plants crown. I have lids drying up, but it could just be shock from shipping. I never refilled the pitchers.
Is my humidity too high? It's seems fine, but it literally rains every day from the condensation on the cover.
Should I sacrifice humidity stability for increased airflow by turning to airflow back onto the plants? Maybe add a constant fan to run during lights-on.

I don't want to shift too many things at once, but I'll write my observations as conditions change.
 
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