5-8 Solution mixed to 750 ppm but should have been 600 max...I forgot to add CalMag after ArmorSI. I did add it after the Micro and ph adjusted with 1/4 tsp ph down. I think its OK...I need to be super careful with VPD or they will probably burn. Put back PerfectPH balancer. Increased light intensity to just under 20k lux. All looks OK but I can tell the PH has been too low for too long. (both PH testers were reading high a while back). I top watered with new solution and set timer to 8 hours
5-9 Found PH at 6.7 this morning. Probably because I used the new nutrient solution to rinse the hydroton from the top yesterday. New PPM meter shows 550, lowered PH to 5.9 (needed more than 1/2 tsp PH down) Roots look great.
5-11 found RH at 38% dammit. Clear signs of stress to match. Humidifier and swamp cooler both ran out of water 4+ hours, my bad. Leaf to air delta was 5-8 degrees. They'll recover by the end of day. I'm double checking the notification systems. Lowered lights to 30 inches, increased intensity 22k lux
i) 5-11 slight curling of edges 4 hours later....lights too intense. reduced intensity to 18k and added 'end' lights.
5-13 Humidifier ran out AGAIN and I missed the notifications. RH was as low as 37% for a few hours. estimated VPD was 1.5+ - More stressed edges. LST - *1st internode is now same height as top. Heat is causing the humidity to be vented out quickly. Its possible the heat from the end lights is a net loss (especially if I keep running too arid)
5-14 Lowered light intensity (16k) and ran RH all the way up to 70% for most of the day to destress these girls (brought VPD to nearly 0). They look fine now. As in the past, this strain seems more finicky than other autos I've grown. Turned off end-lights and 2nd fan too.
5-15 75 degrees 60% 16k LUX @ 1-2 degree leaf delta (low VPD) is about the best I can do at 550 ppm. If transpiration picks up I start seeing stress. (uneven leaf color, edges curl). It seems I can continue to run low VPD at 550 PPM or remix lower concentration solution and try higher VPD. Right now, not all these leaves are transpiring (some are @ or above air temp). So... I am struggling to keep old growth transpiring without stressing new growth. I'll mix the new solution @450 ppm, turn up the lights and lower humidity and see what happens.