[Tiresmoke19]

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?

[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.

[707OGBUSH970]

Im only a forum newb...LOL...

[Tiresmoke19]

Kinda figured it'd be to cold. I assumed that tub would hold more heat, maybe I'll add another heat pad

[Wendull C.]

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]

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.

[igrowone]

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]

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.....

[Tiresmoke19]

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.

[Tiresmoke19]

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.