I am having heat issues in my greenhouse. It is running around 95 during the day. Would a few sugar and yeast co2 generators help? I figure if I sick them behind my fan it will blow on the plants and help.
I grow indoors an when I had heat issues, if it got hotter than 85 degrees, it destroys resin production, it nearly stops, for me that's happened, sometimes burning co2 generators can work against you, just haveing good air flow, fresh air entering an exiting the grow can be good enough, an just wait till it gets cooler in fall an winter, an early spring to run a co2 generator.
At 85 degrees, photosynthesis is reduced by nearly half. At 95, it's about stopped. You have to figure out how to cool it off, and at least get air circulation going. Adding CO2 would help, if you were around 85, but there are several other conditions, too.
You need to get your greenhouses ventilation dialed in sounds like you are running high temps because you dont have enough cold air intaking and hot air exhausting, you should have atleast two fans to move air inside the greenhouse and one intake fan and windows to exhaust. Google search: greenhouse ventilation should help you find what you need
I'm in southern Cali desert, it has been over 90F here on a regular basis. I keep the doors open most of the day time, I have 2 exhaust fans, 2 circulation fans and 2 extra intake inlets for when the door is closed for extended dark. I'm just going to have to get a small window unit (AC) if I want to flower sativas in there. The indicas seem to do well, I think the sativas with their longer flower times would like colder weather while flowering. they don't seem to mind the heat during veg as my 12' tall banana OG attests. I put two of the 2 liter bottle CO2 generators in there and the plants do seem to like it. I have a few indica autoflowers I just started yesterday to replace the one in there now.
No matter how many fans you have in your greenhouse if the ventilation is not setup correctly then you will have heat soak issues. you need to intake air from down below around ground level and you need to exhaust you hot air through the roof or a high up window, if your air is not flowing properly then your gonna have heat issues, also you need to calculate the amount of air going through the greenhouse if you are in a 30x10x10ft greenhouse then your room contains 3k cubic feet of air, so you need fans that can move all the air in the room ever 3 minutes, so you would want atleast (2) 800cfm inline exhaust fans on a 30x10x10ft greenhouse hope this make sense I can send you the link to more info if you like
I'd love the link, ty. Greenhouse is a converted shed 8x8x7=448 cu ft. I have 2 exhaust fans at the top, one 80 cfm & one 45cfm =125 cfm x 4 = 500 cfm (its how I calculated it). However, during the day the doors are open. Its a double door so its like having one whole side open. For dark when its all shut up, I have a 4" passive intake, aka a hole on the bottom of the wall, and a standard HVAC register 6"x12" ? With a bunch of 3/4" holes in it in the floor. Its slightly raised and that's probably the coolest air around. Another part of my problem was over crowding. I didn't know sativas got this big and I was trying to squeeze 6 of them in there! Lucy Yesterday I'm 6' 2" 2 weeks ago Early veg, west side shelf Over crowding
I'll put up better pics of the greenhouse in the AM. Here's another clue: I cover the gh @ 7 PM & open @ 8 AM. Sun comes up around 6:08 and goes down at 7:38. I had just checked to see if I should be in flower yet. 13:30 is getting close.
extra co2 is a great way to make use of extra heat but doesn't solve the heat problem. Contrary to your beliefs, in my experience, sativas usually love the heat and indicas don't. I lived in areas where the average temp in summer was around 110F and the tropical landraces there grew fine, as did some of the more heavily leaning sativa strains...indicas flat out flopped. Might wanna try just increasing the ventilation. If you're in a greenhouse, there's nothing wrong with extra ventilation. Usually plants shouldn't have a huge issue with 95 degrees outdoors. Indoors is another story but not outside...
here's how I'm starting to understand the heat sativa/indica thing: Sativa's are from closer to the equator so they tolerate heat better during veg and cold during late flower. And the indica doesn't tolerate extremes either way because it is from further from the equator. Indicas seem to flower with shorter nights then the sativa, so they start to flower sooner (hotter temps) and finish sooner too, still warm weather. While the sativas start flowering later and can last all the way through November... But there's always the possibility that I don't know what I'm talking about