79 daytime, 61 night: is this a problem?

My grow box is in my garage, which is insulated but not independently heated. It is consistently 61 degrees out there. My 400w HPS heats the enclosure to 79 during the day; it drops to 61 at night. I am currently 3 weeks into flower. Is this an OK temperature swing? Is 61 too low?

some people will say that's too low, hasn't been my experience though.

you'll probably be advised to keep lows in the 65-68 region.

towards the end of things near harvest, i turn off the heat function on my mini split and let it dip into the 40s in there. really brings out the colors. might not be best practice but i'm not trying to build a drug empire or anything. just trying to keep myself in good smoke and put food on the table.

an 18 degree difference is pretty close enough to 15. you'll be fine.
Ive had plants go through a 20+ difference in the winter its not ideal but its not gonna kill em...

If anything some leaves might turn purple

Yes too low. 72 is a good low. The colder they get the longer it takes to warm up and start growing when lights come on.

For optimum yield 85 with lights on and 72 lights out. MIT and a few other universities have stated such. But other temps do great too. Yields a little less is ok to us non professionals. I would be concerned with root zone temp too...... If you want to....

Cannasutraorganics said:

For optimum yield 85 with lights on and 72 lights out. MIT and a few other universities have stated such. But other temps do great too. Yields a little less is ok to us non professionals. I would be concerned with root zone temp too...... If you want to....

Click to expand...

got a link to that?

if i can dial up the temps a few degrees on the mini split, i can save a few pennies.

i've just always heard 77-78 was that "sweet spot" at lights on.

Temp at tops of plants under lights. AC set temp should be dialed in based on setting that temp..... Also silica in the nutes lets them go even higher. But with higher temps comes more nutes used and more humidity to control. Sometimes humidity is a concern some can't control with higher temps. Especially being covert. If useing silica it goes in mix first and is stirred in.

Thanks guys. This gives me some peace of mind. I might pick up a little space heater from goodwill and throw it in there, just for good measure.

Yes, not a professional or growing for anything other than personal use. If I lost 10-20% by weight I wouldn't be losing sleep...

80s can be run if you're using about 1200-1500 co2, 79 tops with out co2, the worst that's gonna happen with temps low at night is you're plant will stretch a little more. Some want the extra stretch, not really a big deal though.