Growing in cool temperatures

Growing in cool temperatures is a problem for many, but I haven't seen much to deal with it. I have some ideas and hope others can contribute.

I'd like to make a grow box of foil faced foam insulation. I'm hoping to get by with minimal air exchange to keep the heat and humidity inside, but have little info on this.

I expect air exchange to be the biggest obstacle to retaining heat. I think one site said three times a minute and that seemed crazy to me. Maybe it was 3 times/hour, but that wouldn't have seemed so crazy to me.
So, is there any good info on the amount air exchange needed?

I guess the next thing is to research and calculate the heat loss through insulation.

lower temps promote mold. if your afraid of mold, keep tent in 75-78F range ALL THE TIME, and humidity at 50-60% AT ALL TIMES DURING LIGHTS ON, and 40-50% light OFF. When lights are off, its very important to drop below 50%, especially if you cant keep the 75F heat constant.

I have a veg room I am running for fun at around 55 - 60 just to see how it goes.

I am having no issues cloning at 60 degree air temp. Everything is slowed down by the cool temps but the plants are growing fine and green. No mold.

I do have one heat mat I use for clones and starts. But no heat at all.

Welcome to cold club

Keeping the RH down at night when it's cold will help mitigate against rot/mold. Warmer moist days make for standing water on cold nights.

Other than that, things move a bit slower.

My temps drop into the 50s at night in the winter, RH swings from 20-50%+ working harder this year trying to keep it above 30 and below 50 or wherever is ideal on the vpd chart relative to the temp.

What are you daytime temps? I forgot to mention, I'm looking at a 2x2 or 60x60 with LED and aiming for efficiency, trying to minimize power used for heating. I'll have more time to get back to this on the weekend. One idea I had is having an adjustable shelf to raise the pots up to the lights.... where it's warmer.

15 c night 18-20 c day. Will plant start flowering? Just Flip and cant get warmer then that

pollen205 said:

15 c night 18-20 c day. Will plant start flowering? Just Flip and cant get warmer then that

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Just exactly the numbers I’ve been dealing with and I’m at week 4 of flower and it’s coming along nicely.

mastrmasn said:

Just exactly the numbers I’ve been dealing with and I’m at week 4 of flower and it’s coming along nicely.

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So the Plant not slow Down ? Have you ever drop lower than 15 c night?
What is you hummidity

Thank you.

It was slower during veg. Worst was 13 a few times. And RH is usually around 55 lights of and down to 35 lights on.

That’s a blueberry just before the flip so size wise they were ok. This was at around 6 weeks I believe. And that’s a 12” pot

What about burning a little bit of propane, like a small stove or heater? Burning propane would create heat, co2, and humidity.
Has anyone tried it?

mastrmasn said:

That’s a blueberry just before the flip so size wise they were ok. This was at around 6 weeks I believe. And that’s a 12” pot View attachment 4282627

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Nice plant

GroDank101 said:

Nice plant

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Thanks. Turned out to be a male. Thinking back it had a nice structure. Should have saved the pollen.

TheTinkerer said:

What about burning a little bit of propane, like a small stove or heater? Burning propane would create heat, co2, and humidity.
Has anyone tried it?

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Be extremely cautious burning anything in a closed area.

You can use infra red: theres led diodes @850nm and there are also ceramic heat lamps. Neither should give off any light.

Rocket Soul said:

You can use infra red: theres led diodes @850nm and there are also ceramic heat lamps. Neither should give off any light.

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*visible light to the eye, put a camera up to them