How Cold Can Cannabis Tolerate?

gaztron3030 said:

Phosphorus isn't taken up by the plant in cold soil temps

Click to expand...

are we talking below freezing?

no, below 15 degrees C

I've got some purple maroc and easy sat outdoor uk had loads of frosts and I've woke up to snow this morning going to go over first light and shake off the snow checked on them last night and they are fine on the up side the cold seems to stop bud rot but yield is down on last year got loads of pics how do I get em of iPhone to here

frost blankets are an easy and cheap solution to overnight temps but gaztron3030 is right phosphorous absorption is slowed down dramatically in cold temps

gaztron3030 said:

Phosphorus isn't taken up by the plant in cold soil temps

Click to expand...

I found this out the hard way, my plants seemed to like the occasional night or two, but a solid week of 40 degree nights fucked up my Indica, but not so much on my Sativa.
All my fan leaves on the Indica turned dark brown/ black from lack of phosphorus and fell off a week to two later, and the growth on both plants slowed with the cold 40-44 degree nights, but the Sativa seemed more resistant to the cold.

They can handle a light frost, but only for a short time. 40 degrees will not hurt them.

60 C? lol I presume you mean 60 fahrenheit, 60C would be 140F which is ridiculously high. And 2 degrees I presume you mean celsius, as 2F would be the other extreme - both of those are extreme lethal tempretures.

I recently started an indoor CFL closet-grow that's within a room with open windows.

At night it drops between 50-60F (10-15C), when the lights cycle off for 5 hrs.

Will the constant exposer to cold nights impact the health of my 2 weeks old plants?

I would be concerned with anything below freezing ( 32 F ) uncovered or for any amount of days if you really care about the outcome of your plant . They freeze . Fruit And Vegetable crops are damaged by a freeze. I have had Mj freeze or get frost bite. Yes it might not heal or could grow back but whats the point. I gow all year outside but as someone posted They are vegged indoor and put outside in a hoop house (covered ) to flower. If it is going to hit 32 f or below they get a little electric heater with a thermostat turned on low. Makes me feel better. lol ! And the hoop house with the heater on is a nice place to burn one when it's cold outside. lol Im not buying into they are fine at 2-4 C or F And watering at night seems to me like the worst thing to do. imho

so cal

i had a small indica outside in the winter as expiriment, it only died when the snow fel and i didnt do anything cause it was december and it gets below -10C out here sometimes. if anything it was fine untill the snow came, i know that purple plants are more winter plants so i can imagine a purple haze being able to fully flower

Anybody know how it works in hydro? I'm growing in a insulated, non-heated garage, In a 2x4 grow closet. I live in a area that temps can drop as low as -35*c/-31*f. My thinking is that I will run the lights durning the night (usually the coldest in the day it gets is -30*c/-22*f). I'll remove my light hood cover, to allow the heat into the grow space, and change my fan cycle from 24/7 to probably on the same timer as my hydro 40s on/240s off. In the lower veg chamber ill put a space heater which will run durning the day (lights off period). I'm hoping to keep the space around 5*c/41*f. I'm sure ill have to tweak this to figure out how to run the space heater.

i also plan to run a propane heater in the main garage area about 5-10min prior to opening doors. Does the res water perhaps need a fish tank heater?

Mine have been thru 30* temps a couple times already, and one night it got down to 26... BRIEFLY...

Depends on strain, but its gotta be below freezing for a few hours to really hurt them.

I've had pure afghani plants put up with 2 back to back nights of snow. They were stunted but finished up nicely with a purple hue. usually the more indica the plant is, the more cold resistant it will be, tropical sativas are not very hardy in the cold department.

like evryone says, you can grow in cold weather. just don't let the plants leafs get hit with frost, or will be game over. keep plants covered, if frost comes. i forgot my plant,in feb and frost killed it over night.

One of mine had frost on the leaves and after the sun came out in the morning it looked fine. That was over a week ago and she is going strong.

I really have no idea about the hydro setup, but my guess is the roots are more sensitive than the leaves and stems to cold temps.

i never get frost till dec, but my leafs where frozen hard, leaf would just brake off. must hae been a hard freeze that night. water will freeze at 32f and below. and in my town. i never seen it freeze past 28 f here. and if it does, man its a big deal, for ag!

stickerbushman said:

everyone here is an amateur? i'm not. mid-atlantic. cannabis is fine fine fine down to the upper 20's no problem, no problem whatsoever, it is not going to curl up and die, not a mature plant, with a little frost, i mean it can get totally frosted and still be just fine. but as the temps go down down down, to those upper 20's what happens is the growth stops anyway, and the cold, damp increases chance of frost and it is time to pull them. i will keep one out until the very end!

Click to expand...

UH OH FOLKS, WE GOT OUR SELVES A VETERAN!! 33 posts since 07 lmfao

Only have a few outdoor plants, but so far it's gotten to 45F a few nights here in Coloado and I've had no issues yet. Just about ready to harvest, so wont be much longer.

Landrace sativas, flowering 22 weeks avg.. I grew year round in the midland-odessa area in tx.... they've survived 100+days of over 100 degree weather and they've survived 4in of snow (most we've ever had) they make it fine in the low 20s for short periods(lowest we expect to hit) but we average 30-40s in the day and I've never lost a plant from temps....that's my 2 cents