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How cold is to cold?

T

Tiresmoke19

Member
I made a set up for starting plants in jiffy pots.
It's a very big plastic tote with heating mat. The 3" jiffy pots and the led grow light I have fitted to top of lid. The heat sinks and fans from light are on outside of lid since I assumed it'd get to hot.

Did a trial run and with lights off, just pad on it gets down to 42 degrees.

With light on it stays at about 56 degrees.

Our ambient air temp in this barn is about 32 degrees

Can I start my seeds or is this to cold?
 
7

707OGBUSH970

No. You really cant. I mean, it is possible that some might, but this would be the lowest end of the spectrum. You should be able to achieve some insulation with a heat source..that would be the only thing...at about 60, some will start to pop, but thats the zone for mold and other nasties. Heat and oxygen are what you need...you can actually achieve heat with even a candle in a small area, but you are asking for trouble. There are ways if you are careful, but that is too cold.
 
W

Wendull C.

Active member
Veteran
It is way too cold. Wait for your night time lows to be 45 and above. No reason wasting, or if you can keep em alive, stunting seedlings when only a lil patience is needed. Imho.
 
troutman

troutman

Seed Whore
If the ambient temperature is that cold you should have waited for it to get warmer.

Anything below 65F will result in very slow growth.

If you can, bring it all inside the house for a few weeks. :tiphat:
 
I

igrowone

Well-known member
Veteran
i'm growing in temps like those right now
it's growing, not as fast as if it was 70, but i'm fine with it
 
aridbud

aridbud

automeister
ICMag Donor
Veteran
Just think if your feet were exposed to cold temps....similar to roots. They don't grow until it's warmer, the soil warmer. Too, jiffy pots notoriously acidic. You'll learn.....
 
T

Tiresmoke19

Member
I didn't actually put seeds in the starting medium yet. Just trial running to see where Temps and rh ended up.

Yes I've used jiffy pots for other plants around the home farm. Our soil here has very high ph (basically on a big lime stone deposit) so the jiffy low ph isn't much of a factor. Tomatoes always worked well so thinking weed should do fine.

I'll be starting a second batch for some other lands where I'll need to bring up ph and will skip the jiffy pots for that run and stick to solo cups.
 
T

Tiresmoke19

Member
As far as soil temp, is there a magic number for marijuana seeds? I read various different air temps but never see any soil temps mentioned.

Our field corn we always wait till soil hits 50 degrees, and beans @ 55 degrees.
 
M

moose eater

With average air temps at or below 50 f., many/some plants go into a near-dormant stage of existence. Limited to no real growth.

A bit of insulation on the outside of your tote, continued use of the heat mat, and possibly a second source of heat into the tote would work at your current barn temps.

Bear in mind that 'too hot' can be as problematic as 'too cold.'

Ideally aim for 70-75 f. for growing plants, and 5-10 degrees warmer than that for young plants/clones/seedlings.

And keep the comic books and television remote control away from them; the lil' buggers have nearly ZERO self-discipline when it comes to such things!!! ;^>)
 
7

707OGBUSH970

Tiresmoke19 said:
As far as soil temp, is there a magic number for marijuana seeds? I read various different air temps but never see any soil temps mentioned.

Our field corn we always wait till soil hits 50 degrees, and beans @ 55 degrees.
Click to expand...

About the same. The magic number is like 60, if you wanna call it that. Ive seen them germinate at high 40's, but growth was slow, and it was seed from a very vigorous F1 hybrid and growth was slow the whole time. You have to remember, that these plants are like little chemical factories. There are optimal temps for certain things, and as you raise it, things happen faster, as they do in simple chemical reactions. Once you get into the 90's, things start to happen too fast, and other problems occur. You might have the seeds crack faster, but often the embryo pops out of the shell without developing enough to make it...
 
G

Guy Brush

Well-known member
ICMag Donor
Veteran
420giveaway
Start them in your living room if you can't wait. When they're bigger you can place the lights-on-cycle into night time compensating for the cold temps and that way also take advantage of the higher day temps when the lights are off. For a late winter comeback you can also still switch the lights on to 24 h for the remaining veg period. Weather forecast for the next 20 days should be studied too.
 
aridbud

aridbud

automeister
ICMag Donor
Veteran
Tiresmoke19 said:
As far as soil temp, is there a magic number for marijuana seeds? I read various different air temps but never see any soil temps mentioned.

Our field corn we always wait till soil hits 50 degrees, and beans @ 55 degrees.
Click to expand...

Corn is the answer. 50F in soil, you're good to grow.
 
E

Easy7

Active member
Veteran
Low germination rates, seeds rotting, seedlings rotting, slow growth if any growth.

Save the seeds for warmer weather. Focus on a good grow plan that natures and times the needs with natural cycle. Something tells me this is not a 420 state. Large 15 pound plants don't hide well.

I'm 41 north and 2.5 - 3 months veg is what we have and that can produce plenty of stash. Depends on the year of course. Usually mothers day to memorial day is a good time to start and plant. Stretch starts last week of july. Harvest up to second or third week of October, or sooner if plants are ripe.
 
TychoMonolyth

TychoMonolyth

Boreal Curing
I'm at 45N and keep them in the nursery for the month of May with a move to the green house the 3nd week before their final home in the ground June 1. If the weather's nice, they'll go in the ground a week early.

I'm popping a dozen GG4 and a dozen Honduran in a couple weeks and are going in the ground mid May. No risk, no glory. lol
 
aridbud

aridbud

automeister
ICMag Donor
Veteran
Getting close....60F soil temp optimal, yet 50-55F works. It's almost time, folks! As other posters mentioned....start indoor, preferably under light, then transplant. If in wooded, varmint area, cover tender plantlings with chicken wire dome. Great growing to ya!
 
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