i have 3 x 600watt HPS lamps in a 6x7 area. 12 plants in FF soil in 3 gallon buckets and FF nutes and calmag. on two occasions my a/c unit kicked off due to the outside temp getting to low and my flower room reached very high temps (100 degrees) for approx 6 to 8hrs. this used up all the moisture in the dirt and made my plants show signs of heat and underwater stress. drooping and dead leaves etc. my plants are in the 6th week of flowering with 3 weeks remaining. do i have to worry about hermies or other permanent damage? i am stressing out. i know i have done this on past grows but only when i was first starting out. i am aware plant growth stops over 80 degrees but just looking for feedback?
Annuals respond well to stress but there is a limit. If you go over that limit you can have a potential to hermie but there's nothing you can do about it now but keep on keeping on. You can disable the outside low temp cutoff. Obviously if you have a load in the room still it's not helping you for it to cause the AC unit to turn off. If that doesn't work you can block off part of the condenser with a piece of plywood to raise the high side pressure enough so it functions well. Plant growth by no means stops at 80. There's growers in warm areas that grow without co2 and hps in the 90's. No joke. Optimal temp with HPS is approx 77 but with led you'll get the most rapid growth in 80-82. Even 84 isn't that bad. That's about where I start to get negative effects. I see many rookie growers that attempt to keep their grow room too cold. The plants usually don't mind 72-75 degrees so much, they just don't grow as rapidly as they do when it's a little warmer. Plant growth is in the end a complex set of chemical reactions. Many of these reactions take place faster at a higher temperature as long as the plant can tolerate it. A plant that is raised in warmer conditions over the whole course of it's life can develop a dramatic tolerance to high temps compared to a plant that is just occasionally subjected to it. Temp and light distance tolerance also varies fairly dramatically between strains and phenotypes. Sativas are hard to burn and generally indicas don't like the light as close or the temps as high. Any Kush strain indicas or going to be higher altitude and higher latitude plants naturally. Sativas are more tropical in general. Higher temps cause higher metabolic rates in the plant increasing feed rate, growth rate, ect.
thank you for the detailed response. now that i am aware that my a/c has the possibility of turning off in the colder season, i will keep a closer eye on it from now on. i also have a outside vent that i turn on when it is too cold for my a/c to work properly. i was just curious if those two times could cause any damage such as hermies or even bud damage etc.?
The extent of the damage is going to vary based on many factors like strain, pheno, local conditions, what temps they are used to, ect, ect. Most plants are pretty hardy and can recover quite quickly from temporary extreme temps or neglect. I've seen them look almost dead and then they'll be thriving two days later with some proper attention. Just stay on top of them and most likely they will just bounce right back. In the end you probably won't be able to notice.
my main concern is they are 2 to 3 weeks from finish. i have done this type of thing with younger plants but never with plants 6 weeks into bud.
just water them get it under control vent it out in the winter like the rest of us do . im not running ac in the winter lol . after you water and the leaves and branches go back to normal your good . not getting technical into this .
I would assume the only reason to use an ac when it's that cold out is to run a sealed space for co2.
If you're not sealed with co2 then your exhaust fan is too small. It's likely all that you need is a higher cfm exhaust fan in 6 or 8 in piped to the ouside to control the temps with a variable speed controller. That's all I use in Alaska to keep my room temp controlled.
i have a 6" in and a 6" out exhaust fan, then i also use the a/c for cool air as well. i usually do not use to intake fan when the a/c is on so that is what happened to me this time. it was just a accident on these 2 occasions but now i have the temps 78 to 82 at almost all times. i was just freaking out when i first seen the plants. i had branches leaning over and lower leaves dead etc. it was scary! they have already bounced back but now i am worried about damage to the buds or hermie possibility!
i have found one male sac so far but that is nothing unusual. i usually find one or two on some of the plants especially when using fem seeds. i plan to keep an eye on them though. i did loose some lower leaves but they seem to be bouncing back over-all. i just wonder if it will effect my yield in any way?
next run will be mostly TH seeds Original Bubblegum! i had 2 of those mixed in with my barneys grow last winter and they were excellent quality.