How cold is too cold?

I have my tent set up in the basement where it can get to the upper 40s. This is my first grow and I'm growing with bubble buckets.
I'm using aquarium heaters set at 66°F but the tent itself is staying at about 60° with the lights and vent fan on.
Is this too cold? Is it required that I vent the pendent? If I turn the vent off the tent should get into the upper 60s maybe 70°.

edit2: one more option is to get a speed controler for the fan.
edit: what if I use one of these to control the vent fan:

Your temps are not optimal, so growth will be slower.

They're growing but slowly; it's going to cost me a $fortune in electricity if I don't figure out an action plan. I ran a quick test on the last 1/2 hour of the lighting schedule... The temp at the plants rose to 78° without the vent fan. Before I spend any money on fixes, I will switch the vent with the lamp and close all the tent-port-vents with the exception of the port at the very top of the tent.
I imagine this is part of the growing pains (pun intended) of learning to grow in New England during the winter.

Maybe try some on off time or temp control like you have posted, perhaps trigger the fan to shut off if temps drop to a certain point

You can grow in those temps but as Bugeye says they'll be slower than in ideal temps, but don't let that deter you at all as it can be done.

The reward of killer bud at the end is the motivation.
Will the pendent or bulb overheat or shorten the lifespan if I turn the vent off?

In your getting the settings right, understand each strain has it's own needs. Knowing your strain is very helpful. Some strains can take cold temps - while another strain will get too cold in the 50 - 60 degree range. You will know it got too cold if the smaller stems leading to the plants turn purple. If that happens - the plant "can" be stunted for a month or more...

Also, You might consider running a day/night temperature controller connected to exhaust to move the air our instead of just circulating the air in the tent.

Check soil temp. Many set-ups have problems if soil temp is below 60f

Getting the air out is the problem as it brings in cold air from outside the tent.
This is hydro and I've got those heated at around 67°F.

Then just move your heat around the space, instead of removing the heat from the space.

I grow in an out building on a farm. It's insulated, and all the heat production comes from my lights. I circulate the heat in the building, and bring in cold winter air when the temps gets too hot.

Sounds like you'll need to do something similar.

Thanks all, it's a 2x4 tent. it would be as easy to overheat it as it is to keep it too cold.
Hopefully some creative venting will fix the problem.

a little automation and some learning curve and you should be able to sort it out

Clutchcargo_1 said:

Thanks all, it's a 2x4 tent. it would be as easy to overheat it as it is to keep it too cold.
Hopefully some creative venting will fix the problem.

Click to expand...

What will you do when your lights are off? In flower you'll only have heat producing lights on half of the time...

Maybe you need a second tent and more lights

a senile fungus said:

What will you do when your lights are off? In flower you'll only have heat producing lights on half of the time...

Maybe you need a second tent and more lights

Click to expand...

The classic flip a flop, use the heat from the "on" tent pumped into the "off" tent, great advice.

CannaBruh said:

The classic flip a flop, use the heat from the "on" tent pumped into the "off" tent, great advice.

Click to expand...

I bought a dpdt relay from eBay for $8, it flips my lights in two rooms, off of one timer. That's how I keep my place warm, either two gavita 6/750s or a 1000w single ended is always on, in addition to veg lamps.

That's a great idea but might be a bit outside the scope of my operation.

Experimenting with a high tech solution. This gets me to the mid 60°s.

Vent less! You only need to turn over the volume of the tent, once every hr!

A cheap ceramic heater in your basement with a built in thermostat to prevent the temperature dropping below 60 would be the obvious easy fix. If your basement is too big, then hang some blankets or tarps and fashion a small room around your 2x4 tent... like a tent inside a tent. Hell, you could put a little one right in your tent. It will only come on in the middle of your dark cycle and then for only a few minutes. You can get them for less than $30. Personally, I can't imagine your plants ever get that cold with a heated root zone so I doubt its a problem. That heat should transfer to the plant. I am curious how your grow works out. I grow in a NE basement as well, and I still have to ice my DWC buckets to keep them cool enough to prevent the rot but my basement never drops below 63.