What's new

We have How Hot is Too Hot? How about how cold?

vicious bee

Member
We have How Hot is Too Hot? How about how cold? Will autos sprout in cool weather? Will they grow outdoors in the 50F or 30F? Will they take a short freeze or frost? How much does low temps. slow growth?
 

stevefrench

Active member
if i remember right IceColdCrickets did some testing with autos at low temps, trying to extend the veg period/delay flowering or something of that nature, maybe he could chime in here but i think he managed to get an auto to veg for 42 days in cold temps.


i started a bluestreak a couple of weeks ago to see how they can hold up to cold temps outdoors up here during the canadian fall/winter.. im curious to see how they do in harsh conditions

dscf9641z.jpg

gonna do some LST as well :smoke:
 

blynx

WALSTIB
Moderator
ICMag Donor
Veteran
if i remember right IceColdCrickets did some testing with autos at low temps, trying to extend the veg period/delay flowering or something of that nature, maybe he could chime in here but i think he managed to get an auto to veg for 42 days in cold temps.

Most of my stuff, including non-AFs, veg's at low temps and it totally slows down (delays) development of AFs.

If you look at some of the ages of the AFs I've grown;
Masterlow 1st Run
Creating an AF strain - 1st attempt
Massive Masterlow Harvest
Mossy's JEM 1st run

you will see that most of them have 'vegged' for a long time.

They were just kept in low light, low temps, and smaller containers until I had time to deal with them. Then they were transplanted into larger containers, put under more light and warmer temps. Once that happened then plant growth resumed to what most people would consider 'normal'.
 

*mr.mike*

Member
If you want it to keep growing well, 50F is about as low as you'd want to go.

45F and below is where damage occurs. It takes about a week for a plant to get over that kind of exposure for a night.
 

vicious bee

Member
Great information. Thanks. blynx- A question of clarification. Did the plants under cold temps go into suspended animation? For example: An eight week flowering plant under one week of cold goes nine weeks or did they stick to their eight week period. When you say growth resumed normal does that mean the final yield was the same or that the growth per day resumed same but the final yield was less? Thanks Again
 

blynx

WALSTIB
Moderator
ICMag Donor
Veteran
Great information. Thanks. blynx- A question of clarification. Did the plants under cold temps go into suspended animation? For example: An eight week flowering plant under one week of cold goes nine weeks or did they stick to their eight week period. When you say growth resumed normal does that mean the final yield was the same or that the growth per day resumed same but the final yield was less? Thanks Again

I don't know about suspended animation, but growth is certainly really slowed down. They don't 'stop' developing, they just develop very slowly compared to warmer temps.

I've never grown a plant to any size in warmer temps and then put it into cold temps to slow it down. My guess is doing that would cause the plant to produce a bit less and still be done in about the same time.

I would also have to guess that the early 'veg' in cool temps does somewhat affect the yield, ie lowering it a bit.
 

*mr.mike*

Member
I've grown a few af plants at temps just under 50 F a few times. They simply stopped growing, or grew very little. I had no room in my grow space, and had to put them outside for a while.

When they were put into a warm place, they sprang back to life. It was as if they had never been in the cold, and the two weeks in the cold meant I had to grow them out an extra two weeks, with no noticeable difference in yield and no difference in quality.
 

medmaker420

The Aardvarks LED Grow Show
Veteran
I just asked one of the above questions on another thread. My girls are draggin ass growth wise. Temps during the night is 55f and daytime around 65f at most. I just put something underneath them to get them off of the floor and am thinking of insulating the tent OR possibly tossing a heater in the room they are in during nights out. Any type of small heater scares the shit out of me especially when it is at a secondary location.

So pretty much as the temps go up they will wake back up and finish as usual BUT a week or two late then?

I am hoping to get a veg tent going and just vent that warm air into the flowering chamber versus getting a small heater. Hope that helps but am worried about my yield with these cold temps.

So keep em above 50 no matter what BUT preferably above 60 works best then?
 

SmokeyTheBear

Pot Farmer
ICMag Donor
Veteran
at 50 degrees MJ slows almost to a hault. pretty much not even worth your time. any colder than that and your plant is just something to look at it. it won't grow at all. i've found with my outdoor in the summer that they will still grow, but slowly when the temps are 55 degrees and higher during the day. these were with autos and regular cannabis plants.

if outside it really won't matter how hot it gets, imo. unless it's a very dry climate then you might get some sunburn on the leaves. if indoors anything above 85 degrees is too hot. they will grow but it's not really what you want.
 
Last edited:
just set this little guy jd deisel ryder out for a 29 deg f nite.. hoping he dies lol well see how long he last at 50 for highs and 20-30's for lows....
 

Attachments

  • 100_1312.jpg
    100_1312.jpg
    37.9 KB · Views: 9

vicious bee

Member
Where mine were growing it got too cold so I just left the lights on all the time. Thought about a heater but why not use lights and get some growth.
 
Top