I kept struggling to keep RH and temps on optimal and constant levels, but managed to fix it.
Swapping to the HML introduced problems, The plants looked "cooked" with very pale green turning to yellow.
After analyzing it I came to some conclusions:
- It generated too much heat
- HML had too much red LEDs (as I designed it to flower sativas)
- It was too close to the plants canopy (around 10cm/4")
To fix two birds with one stone (heat, and too much red) I disabled the red LED strings: I simply disconnected the 24x XP-G's (about 60W) and left the 10x XM-L (around 90W). As I put inline fuses from the drivers to the LED strings, I simply removed the inline fuses for the red LED lines to disable them.
To gain distance to the canopy, I attached the HML as high as possible, had to be on a fixed manner, to let about 12"/30cm to the canopy, as the XM-L are rather powerful (10W) with lots of penetration.
I don't think there will be any need to lower the LEDs, and hopefully this will have the added benefit of creating more stocky plants, something good as I'm very fond of sativas. If it still too powerful for seedlings, I may just simply prop a "shade" using translucent plastic for seedlings once I have seedlings / moms / cuts mixed in the vegging chamber, or add the PLL back between the two HML bars for seedlings if temperatures allow.
Temperatures finally turned to optimal values.
I had a mist humidifier constantly on. RH was not steady, now that temps were in good ranges I needed to fix the RH.
The fix: repotting the plants to 1L pots. They needed it anyway, and having 10L volume of moist coco keeps humidity closer and stable to more optimal values.
I have found dialing in RH in the grow area is most times a matter of finding the "sweet spot" for pot size/plant number, specially when running coco. De/Humidifiers help, but cannot keep such "steady" levels and struggle.
I use U-Gro 11L coco bricks, I have found it to be really good quality. I just add 3L of tap water to it. I repotted all the plants and gave them a 2/3 strength dose of rhizotonic and B52 (0.9EC/PH 5.8). For curiosity I measured the runoff after watering: 1.3EC, PH 6. Looks pretty good IMHO.
Right now I haven't finished to build the mycodo/raspberry/sensors rig, so humidifiers/extraction are run from timers. After letting them alone for 6 hours, I found RH lower range was spot on 60-70%, but RH had peaks of 95%. Not good...
To fix this, I went from having the humidifier 24/7 and extraction 15 minutes each 1 1/2 hour, to run both from the same timer, 15 minutes each hour, so that humidifier "makes up" for the lost humidity.
Now RH hovers between 60-80%, great!
Girls started turning greener and surely will recover soon perking their lovely leaves towards the HML! They had healthy root balls, so I'm positive things are going to take off.
They're one month old now and look clearly underveloped and droopy (my fault, I cooked them with lights too close with too much red) but... these things happen on new spot first stealth grows
I was too confident but truth is I'm rusty!
Taking the big jug with the humidifier mister out of the tent, and re-purposing it on an external jerrycan-like sealed container, will use an aquarium air pump to bring humid air through a couple hoses to the vegging tent.
I'm not happy running humidifier/extraction each 15 minutes, is too much for the size of the tent but that's the minimum I can run on my mech timer, my digital one supports only 1-minute resolution & 8 daily programs; I may try it and run extraction/humidifier each 3 hours for e.g. 1 minute until raspberry is deployed.
I have to fix an issue with electricity going there (no neutral), then will deploy the raspberry.