at what temp should i cover?

Discussion in 'Growing Marijuana Outdoors' started by MN_northernherb, Sep 30, 2010.

  1. at what temp should i cover my plants? 32? 34? 30? its suppose to get down to 34-35 on saturday so i'm trying to decide if i should trek out there and cover them or not.
  2. where you at? im in PA and wondering the same thing. what are you using to cover?
  3. minnesooooota. lol. i'm gonna use a tarp and weigh it down with some rocks, but is 35 cod enough that i should cover them? what temp does it take for frost to form?
  4. Lmao no offense man but did you ask what temp frost forms? 32 degrees F, and Yes I would cover them if its getting that low I draw the line at 40 degrees F and start getting anxious.

    I myself am growing in MI outdoors and am harvesting tomm because this next week is bringing temps of 40-44 night time lows and im not takin chances.

  5. I am not from MN, but I think it would also have to do with wind chill?
  6. I knew to all forms of gardenning where frost occurs. I am originally from SoCal. Only had frost once in like 10 years.

    What do you cover plants with? I am in SW Oregon now. Can I just wrap plastic around them? Or burlap?
  7. I am 60 miles west of Minneapolis... I have not seen any forecast suggesting lower then 33 so I am just gonna let mother nature takes it coarse... I have 5 different locations, all doing very well with about 10 to 20 days left to finish.

    If I had the ability to cover them I would... my sites are so out in the open that I can only visit them in the dark and cannot even use a light (it has been challenging) so covering them would be like a turd in a punch bowl.

    here's my take: a light frost can happen in low lying areas at 32 f. any breeze at all be prevent the frost. if it warms up quick enough in the morning all should be good at 32 f. A hard freeze occurs at 28 f and will kill any plant regardless of the wind.

    I am risking 10 plants that are on coarse to yield at least a couple of pounds... hope my gamble pays off...
  8. It has been about 44-47 att night in my area. Some of my babes have been turning purple leaves and whatnot but they still healthy. I am going to harvest abut 1.5 weeks as weather permits. If ur temp is in the 40s u should be ok anything like 35 and u should cover and be safe
  9. anything that will not let rain thru. plastic trash bags if ur plant is small enough, sometimes i will use a few of them to cover the whole plant. one of those big tarps work, but they are heavier so ur plants need to be pretty sturdy/strong
  10. alright forecast says 36 for tonight. i think i'm gonna try to cover them just for safety, thanks for the help.
  11. If I were to cover mine I wouldn't use plastic... it really isn't that good of a insulator. the idea is to trap the heat from the ground so be sure to cover them as early as possible (don't wait until it has gotten down to 32) keeping the moisture off 'em too. Unless you want to try an old trick by watering them down like they do with fruit trees.

    Also, set a few 5 gallon buckets of HOT water next to your favorite plants... and use that water in a few hours to water them... add nuts as needed :)

    I plan on watching the weather... if it gets down to 32 f I may just hurry and top a bunch of 'em... split my loses... I have to be done before sun up...

    It is supposed to warm up fast in the morning...
  12. go to and subscribe to their daily sends you the low temperature at night in your area...very easy and alot less stress because you dont have to check the frost advisery.lovely stuff
  13. all good advice, thanks everyone
  14. I forgot to cover mine up last night and they got some frost on them, I'm wondering if there gonna make it now? Im also in MN,

    OP what did you end up doing?


    Uploaded with

  15. I cannot visit my sites in daylight but I can see them... one of my sites looks just like your photo (wish I could have snapped a photo of mine) I am sure it will make it... in fact, I think it will help it to finish with the nice weather we are going to get :)

    unless your plants got down to 28 f for a significant length of time they should be fine. the frost wasn't on them for more then a few hours... temps are in the 50's before noon, 50% humidity and a gentle breeze should help a lot!

    It is gonna be a great week or two coming up... I am getting very excited.
  16. it didnt quite get down to freezing last night where i am, i put some cedar mulch around the base of the plant and called it good (for insulation? i hope thats ok), i have bigger fish to fry now... my spot has a light leak. (i talk about it in the thread in my sig). i'm an idiot.
  17. The street light may have caused your plants to flower late but I do not think it is an issue at this stage... I think it is the sativa dominate stain needing a longer flowering cycle... my understanding is outdoor grows do not suffer "light leaks" as do the indoor grows... you said it wasn't brighter then the moon

    There is a big difference between natural sunlight and a street light.

    BTW, I have 5 swiss cheese, 4 aurora indica and 4 ak-48 and one short rider (that didn't auto flower) all from Nirvana I hope to take some photos
  18. #18 Lil Sis, Oct 4, 2010
    Last edited by a moderator: Oct 4, 2010
    I was surfin' the web for info on frost, I came across this and thought I'd share. Good Luck to you all! ;)

    Plastic can be used to protect plants from frost, but it’s not the best or most effective material, and some expert gardeners warn against it. Plastic or vinyl materials do not breathe, causing moisture to get trapped inside. If the temperature drops low enough, the increase in moisture presents a greater threat to the plants. Instead of plastic, try using natural fabrics like cotton or linen, an opened burlap bag, or newspaper, as a covering to protect plants from frost.

    A fabric covering will allow moisture to escape but will still protect plants from frost by preventing the freezing air from coming into direct contact with the moisture. Bed sheets work well for covering large plants and shrubs, as well as young sprouts. Newspaper can be used on low-growing foliage, but won’t stay on top of larger plants well.

    In a pinch, you can use plastic sheets, but be sure to remove the plastic covers early in the morning to let the increasingly warmer daytime air reach the plants. If the threat of frost is prolonged and temperatures remain low during the day, be sure to use a fabric covering. When there is a threat of frost, cover your plants before sunset.

    You can also purchase commercial coverings designed to protect plants from frost. These may be more attractive than other methods, but usually bed sheets or burlap work just as well. If your efforts to protect plants from frost fail, you will have to allow nature to take its course. If you have vulnerable plants that would be expensive to replace, it’s best to try to protect them.

    The cold, cloudless evenings in the fall, winter and spring may be harmful to your plants. During the day, your plants and the soil absorb and store heat from the sun. As the day turns into night, your plants quickly begin to lose all of their stored heat. Clouds will help to insulate and slow the loss of the heat, but a cloudless, wind-free night will afford no protection from frost. The temperature within the soil and in the plant’s cells may even drop to a few degrees colder than the air.

    As the temperature decreases, the moisture in the air condenses into dew, which then freezes when the temperature reaches 32 degrees F. on the plant surfaces. At 32 degrees, damage to most plants may be minimal and only affect a small amount of leaves. However, if the temperature drops far enough for the plant cells to freeze, non-hardy plants will die.

    Frost can occur even in supposedly frost-free areas. It is important to heed the weatherman’s warnings of ‘a chance of frost,’ and take precautions to protect your garden. It is possible to extend your growing season by several weeks if you are able to keep your plants alive through a single early frost!
  19. I am growing outdoors in Michigan as well. It's supposed to be around 38 degrees tonight. I have read that the plant handles frost better if the bucket it grows in is burried in the ground, is this true?

  20. that is true, the ground helps retain heat through the night.

    and good info lil sis

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