FROST: general rules from experience....

poplars said:

Anything else I should edit into this guys? or is it pretty solid?

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I think it is pretty solid, but this is my first year outdoors. I have learned a lot reading through this thread and it made me feel more comfortable about frost. I appreciate you all taking the time to write such great, reassuring info for us beginners, & everyone for that matter!

I read somewhere (May of been in this thread) that if you have a frost for an extended period of time to water with warm water to keep them going.. (Kind of like the sprinkler idea, but warmer water) What do you all think? My only concern would be if recently watered, causing root rot, or the water evaporating causing artificially high humidity which could cause mold?

I would prefer methods of using wind, or tenting to that.

damn ive been away from my plants for 3 months and they were flowering when i left

im going back to Virginia after its been in the 40s and frosted a few times

but @poplars thanks man for this guide its making me optimistic and hopeful that my girls aint F.U.B.A.R

im going back this Tuesday so im crossing my fingers there okay

poplars said:

Anything else I should edit into this guys? or is it pretty solid?

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what about snow

I live in colorado and grow in the high rockies. I'm also not a fan of auto flowering. ( in my experience I don't get as flavorful buds) I have had plants start to loose leaves after 32 degrees while some did just fine. I just try to water less if I know of frost coming, or if my plants really need it I water early in the morning. I don't know the exact reason but it seems to help. We didn't have much frost this year. (rained like crazy and stayed warm till after halloween, made for an awesome late harvest)

My frost solution

Frost and snow...
Depends on how long...
I have a couple of plants that have been frozen crisp multiple times. One AM I went out and they were covered with ice and snow. I hauled them in and they are OK. Not kickin ass, but OK
I think a certain amt of resistance is strain and age dependent.
not to derail the thread
but does the plant's chemistry change to deal with cold?
My plants get frosted consistently, overnight, thru the winter.
It does get up to 60`F in the day...

I heard when breeding, the strains adapt to their environment. I don't have any facts to back this up though so idk.

entertainer1224 said:

I heard when breeding, the strains adapt to their environment. I don't have any facts to back this up though so idk.

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When seeds are producing outdoors the flowering time reduces I believe...

When I worked in Mendo, we got some heavy frosts that fully encased the buds. We would spray lightly with water before the sun hit them because, the extreme temp difference from frozen to sunlit would make the buds turn to mush. Seemed to work for us.

Things to consider, some strains are more sensitive to frost than others, if they are in pots this can make them more sensitive.

Sativa strains tend to be more sensitive to frost than Indicas. Indicas and Indica dominant hybrids are capable of handling frosts as low as 28F. but there have been reports of sativas handling frosts just as well.

I'll leave this sticky open to discussion for other experienced users to post their experiences, I will compile it into this. I felt this was needed as this question gets asked a lot when a frost comes by.


you can protect the plants if they are of manageable size or if you are handy enough to build a sturdy setup.

this can be as basic as a pvc greenhouse with plastic wrapped around, or even sheets if properly secured to not touch the plants... or as large as a full car port with greenhouse grade plastic secured.


how much the temperature rises the next day also tends to define how the plant deals with the frost. if it frosts and it rises up to 65 degrees+ with sun in the daytime, the plant is much more likely to take the frost and keep growing vs a plant that takes a hard frost and sees a 45 degree day with clouds....


cooler temperatures (55-40 degrees F) will definitely bring out some purpling in some strains, and cause flowering to speed up, nights that dip into the 35F zone boost this even more, bringing out even more color.

sorry for the organization of this thread, guess I'm too much of a stoner after all [/QUOTE] I had an orange Bud out side this year, when it came a hard freeze, 20 degrees with a 20 + North wind all night for over 16 hours before warming up. Some picture's of before after, I had to trim off the fan leaves, because as you can see, they all died. The rest of the tops survive, and the last picture is what it looks like today. Long story, they can take a lot of crap. happy growing

poplars said:

Lots of strains of cannabis can handle a pretty strong frost. I've had plants handle frosts as low as 28 degrees F without killing the plant.

Things to consider, some strains are more sensitive to frost than others, if they are in pots this can make them more sensitive.

Sativa strains tend to be more sensitive to frost than Indicas. Indicas and Indica dominant hybrids are capable of handling frosts as low as 28F. but there have been reports of sativas handling frosts just as well.

I'll leave this sticky open to discussion for other experienced users to post their experiences, I will compile it into this. I felt this was needed as this question gets asked a lot when a frost comes by.


you can protect the plants if they are of manageable size or if you are handy enough to build a sturdy setup.

this can be as basic as a pvc greenhouse with plastic wrapped around, or even sheets if properly secured to not touch the plants... or as large as a full car port with greenhouse grade plastic secured.


how much the temperature rises the next day also tends to define how the plant deals with the frost. if it frosts and it rises up to 65 degrees+ with sun in the daytime, the plant is much more likely to take the frost and keep growing vs a plant that takes a hard frost and sees a 45 degree day with clouds....


cooler temperatures (55-40 degrees F) will definitely bring out some purpling in some strains, and cause flowering to speed up, nights that dip into the 35F zone boost this even more, bringing out even more color.

sorry for the organization of this thread, guess I'm too much of a stoner after all

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I have grown close to 20 different strains all outdoor in Denver and have experienced hail, down pours, frozen rain, frost, and even snow in late flower. I have literally came out in the morning and have my plants covered in snow and I'm like god damn it but I just shake them off and they are fine. I have NEVER covered my plants at all. I grow mostly Indica strains mostly because of preference. Almost everyone I know that grows outdoors covers their plants in cold weather. I'm just lazy and have never had any negative experiences. Not to say it wont or cant happen but I haven't experienced any losses. The worst that has happened is that I have had limbs break over being wet and having heavy colas. In my experience, the worst weather problem for me has been the wind. When you have big heavy buds the branches tend to break. I try and stake and support the branches but shit happens and that pisses me off when a huge branch breaks off the main stem. Anyways, thats my .02

I usually heat up some jugs of water or big rocks, put them around the plant and then cover it with a tarp making a small micro environment. It's a P.I.T.A when you have to do it every night for a couple weeks. From what I've read, If your plants do get heavily frosted, you should hit them with a hose before sunup, something about it is a slower melting process than letting the sun do it and mitigating plant tissue damage.

I once had plants get a complete covering of ice on them and bounce back with minimal damage once they thawed out.

so I guess when the frosts start pull em out? or the frost may ruin them?

2d9s said:

the first frost of the year was on sunday night, i checked my pumpkin patch today - tuesday - and everything seemed fine. the temperature dropped to -1*c so it wasn't a hard freeze - the weather network also posted a frost warning. the only difference i found was that top colas were 'browned' and withered a bit but the rest of the plant parts (colas underneath, leaves, stems, roots etc..) seemed intact.

here are two photos of the top cola of one of the plants. the first one is from friday (before the frost) and the next one is from tuesday (2 days after the frost).

hope it helps as i had no idea what to expect as well...

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what time of year mate?

Laney said:

I've never had frost kill a plant and I tend to leave them alone to ripen, weather or no. That's because, in most places, there will be one or two light frosts (like I just had) and then a clear spell, during which the plants will quickly ripen. I've lost a lot of leaves from these weather dips. The buds are fine, though. I guess it'll just make trimming easier

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its early april now, when should i think about harvest? im in canterbury, not sure of strain... sorry just need a rough guide, apart from trich and other signs

when a new season starts i basically just take the soil from the last year, fill them in pots and plant the seeds in there. the only thing i do is to cage the plants against birds for the first 2 or 3 weeks. had never problems with low temparatures even with light snow. of course they germinate very slow but this is one way to assure only strong plants are in my guerilla spot. may they get killed when the temperatures are extremely low, but i like to risk it because the harsh climate in early spring gives robust plants ant there is also plently time left to replace them just in case.
cannabis can take some serious abuse, i had some plants abandoned in early stage in small pots last year because i thought the spot got busted. they were on their own in harsh climate which means coldness, wild animals and little water in times of high temperatures.
i sneaked a month later to my spot just to find my plants healthy and bigger. toke the best with me in my backpack and planted them in another spot lol.

This is one of my blue widow from Dinafem it's been pretty strong so far I started them inside about April 20(germination) they were only outside for about two days before the frost hit , and they were to far away to just go cover so I had to take the chances .... But they took the cold like a champ! This is one in a 5g pot as well , it did end up falling over but she looked to be growing well anyway , VERY strong strain in my personal experience . #dropseedsnotbombs

Michigan here. Frost kills plants, freezing kills plants, snow rain and cold brings in mold botrytis and that kills plants. I noticed nobody said anything about young plants or larger ones going outside in the spring. Its dropping down to 28f tonight and tomorrow. I'm trying out a couple heaters in the greenhouse to see it I can keep the temps up. If not then I'm moving everything inside until morning. I left one outside in 27f for one night and it died.

Really helpful information. Thank you! I have seen sheets and towels over plants before when it's been frosty outside so I'm really happy to understand that now and know what temperatures to keep in mind. I already understood a little about what sativa strains and indicas preferred thanks to another grower's education but had forgotten some things.. Thank you for all the details!