Temps,how low is too low?
- Thread starter bluesdad
- Start date
vostok
Well-Known Member
C or F...I like to think that 13c/20f is the lowest my babes can stand, tho autos will go down to 7=8c/14f? with ease ..all plants can drop very low, but only as a temp basis, theres many tricks to preventing your plant from freezing, the best is putting a small light bulb in a cookie bin, creates heat and warms the average room 10x10ft
m3d1c1n3man
Well-Known Member
I'm sorry, but you said "13c/20f"??? 20f is below freezing (32f) and 13c is above freezing (0c). So in other words your statement makes no sense, no offense.
I would say that the plant can probably survive anything above freezing, 0c/32f. It may not grow very well at temperatures below 60F, but shouldn't die. It is a freeze that kills most plants. Anything below freezing and you could be risking death.
Rocketman64
Active Member
My experience with the cold showed me a couple things of importance. A previous poster pointed out that cold is okay, freeze is not. I've had plants in my attic grow room withstand temps in the high 20'sF. Generally speaking, this temp only last a few hours until lights come back on. I've found the plants don't mind the cold so much if the high temp is not extreme. In other words, try to keep temp fluctuations from becoming extreme. You don't want 95F when lights are on, 20F when lights go out. Flowering plants love the cooler temps when lights are off but avoid huge temp swings. Secondly, humidity can be a killer. I recently lost a beautiful Killing Fields because my humidity levels in my flower closet climbed up on me. I was foliar feeding during the first hour of lights on cycle. The low temp that night hit 30F, not usually a problem. With the extra humidity in the room, I hit the dew point by accident overnight and created a 'frost' situation. That one night of frost was enough to shock the plant. It took almost three weeks but the plant spiraled down hill and died. Obviously, anytime temps are below the freezing point there's a risk of damage to plant cells. Ambient temps in your grow closet can be lower than freezing but not for a sustained period of time. Water takes awhile to adjust to ambient temps. Being that your plant is comprised of cells containing water give you a very slight buffer zone. The moisture in the plant will not instantly freeze when temps go below freezing but over a period of a couple hours, the risk is there for sure. Also, your grow medium is storing heat as well. Just the fact the soil is above the freezing point allows for a slower drop in the ambient temp. When the lights go out overnight, the temp in the grow closet will very slowly drop. You may not even hit the outside ambient temp by morning depending on how your closet is set up. I've had outside ambient temps around 0F overnight and with no heater in the grow closet still kept things around 35F overnight. I would suggest keeping some kind of heat source available to the plant if you suspect the outside ambient temp is approaching the 30F mark. I have a pretty cool little mini heater I made for my 2x2x4 attic grow closet using a light bulb and a piece of metal tube. It's set up so no light leaks from the unit (it's in the flower closet, no light allowed). It's quite versatile because I only need to change the wattage of the light bulb to adjust the heat it puts out. I generally run a 25w bulb to keep temps in the 40's overnight even when it's way below freezing outside. I can post a couple pics of the heater if you're interested. Good luck, my friend.