My outdoor grow is getting cold, but I think I'll make it, we'll see

This is a post to track the progress of my outdoor grow.

  • Hindu Kush (Sensi seeds)
    I got like 12 extra seeds that came with my 30 Hindu Kush seeds from seedsman:
  • Jack Herer Fem
  • Critical purple kush
  • Magnum auto fem (trich picture)

I planted the seeds around Aug 22nd. I transplanted 10 plants on Sep 2nd. I was naive, in the beginning, because I believed that if they grew in a greenhouse, the greenhouse would retain a decent amount of daytime heat. I was so wrong, LOL! With no added heat protection, the greenhouse was maybe 2 degrees warmer throughout the night. I got a mr. buddy heater to heat it up at night and added mulch to the plant beds with freshly chipped tree limbs. The last straw was when the buddy heater turned off on me in the middle of the night because of low oxygen (I wasn’t ventilating the greenhouse) and it got to around freezing in the greenhouse. The plants outside had frozen dew on them, but my cannabis had no frozen anything on it, and 2 days later, they are all still green. Additionally, my greenhouse isn’t REALLY structurally sound, and my landlord calls the heater a fire hazard and says I can’t run it when I’m sleeping, which I understand is totally fair. I also think a few of my plants that are in veg have been stressed by the cold, hopefully my solutions will help fix that. I’ll have to see if it herms :call_me_hand:

So, this is what I’ve done to try and move past this. I reduced the size of the greenhouse by 25%. I also added a second layer of polyethylene 6mil fabric. I added 1.5 feet of freshly chipped trees to the whole greenhouse. The decaying matter is getting hot in the big pile we had dumped on the property and should add a few degrees of ambient heat. I also put in 3 black garbage cans filled with water to help add ambient heat. I plan to add boiling water to each of them every night before bed when I turn off the heater and close up the vent. I also went out last night at 2 am to turn on the heater for a bit. Keeping it in the 50 degree range would be aweeeeeesome.

Humidity is great this time of year, with around 50% consistently during the day. Highs are estimated in the 60s and some 50s, but the highs don’t really matter because it gets up to 85 and 90 in the greenhouse during the day, just from the sun. Lows are projected in the high 30s and low 40s for the next month or more, but we’ll see.

I ordered the Hindu Kush from seedsman with Bitcoin over a year ago. They are supposed to be seeds from Sensi Seeds, and they are regular not feminized. They came in the original packaging and didn’t seem to be tampered with. They also do look like Hindu Kush. HOWEVER, all 7 of my seeds turned out female. Not sure the odds of getting 7 straight females from reg seeds or if they are not what I bought. Maybe they accidentally got feminized? Idk


That’s a lot of information. I’ve been racking my brain on some sort of solution to help you out a little bit. If you have the supplies maybe makes some sort of insulated frame box or something that you could put over them to keep the heat a little bit better or I know that sounds like a pain in the ass I wouldn’t want to go that route. Or maybe eat that Greenhouse up to 90° 85° somewhere in there before you go in for the night maybe with a bigger heater a nipco or something. If you have an indoor setup maybe cut some clones take them indoors, Re veg them start all over.

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Maybe put your heater on a timer and a couple hours before it gets light out have it turn on if possible. Or maybe talk to your landlord put some sort of metal plate or frame something that is not and cannot start on fire to ease your landlord’s mind a little bit that way if he’s worried about it falling over and starting a fire it can’t and then maybe he will or she will let you go about your business

I’m kind of already at my max for budget, but I have one more idea that could help me stay asleep through the night. That is to get a large metal 55 gal barrel, and boil the water over a wood fire and fill the trash bins with the boiling water before bed. I feel like it would work, although im still not sure. Also adding more actively composting mulch today. The greenhouse stays warm enough until 3 or 4am when I can wake up early and turn the buddy heater on again.

Welcome , I’ll tag in @Caligurl may have some good advice on greenhouse grow or know other members. :+1::v:


Sorry, I don’t have any experience with greenhouses (yet). I do know that, mold is always going to be an issue unless you have great air flow. It worries me other about pouring boiling hot water on the mulch to keep it warm inside? That sounds like making the grow space into a sauna.

Maybe @Myfriendis410 or @AfgVet can think of someone to tag who does grow house grows throughout the winter.


No boiling water on the mulch. I pour it in 3 x 40 gal black plastic trash bins from Ace Hardware, and they all have a lid to keep the water from evaporating. Great airflow during the day, not so much at night.


This gal has been outside since August 27th and the last 2 weeks have seen temps as low as 35, multiple days with lows in upper 30s low 40s and she’s been awesome, had slight purples when it was warm but ince temps dropped she went monster purples. Daytime temps ranged from low 90s to upper 50s entire time outside. Think you’ll be just fine.

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I would say watch for frosts and if possible find a way to drape a very light sheet over the plants at night if it is forecasted to frost as that will help keep them from frosting. Now if you have freeze warnings do the same and hope it’s not that bad. The heater idea would help in a greenhouse i would think, just dont crank it because it will dry the air out a lot.

Thanks for sharing that, good to know! Hoping for some nice purple too.

Here’s an update to show other the success I’ve had growing in the greenhouse and how I kept the temps up.

  • I added a second layer of 6mil polyethylene plastic sheeting
  • I loaded the inside of the greenhouse with decomposing mulch
  • I buried the edges of the plastic sheeting all the way around the greenhouse, then I added ~ 15 wheelbarrows of actively decomposing mulch around the walls of the greenhouse

These are my results from a really cold night last night. Left side was the record low outside and on the right was the record low inside the greenhouse last night. I also added 2 additional pictures of temperature readings I took lately.