Uninsulated Room/Tent Grow

Hello all, first time poster, second time grower.

I grew two tiny auto-fems two years ago in my basement crawl space. I yielded about two ounces without knowing jack about growing anything, let alone pot. Fast forward two years and my state has legalized recreational MJ and I can grow legally!

I also bought a house but I have many guests, and while legal, pot growing is still stigmatized. Hence, I am utilizing an uninsulated room below my three-seasons porch. I live in MA, and we get some very cold winters so I am worried about keeping the grow environment suitable for my plants.

I am growing two (maybe 3) white widows in 5-gallon Home Depot buckets. I plan on LST or maybe even SCROG. I have a 300W LED and two 15W LED bulbs for pointed lighting. The tent is 48x32x60. I have a heater set on a temperature plug that will turn off at 78 and on at 72. So far, the coldest the room where the tent resides has gotten is 32. That was on a night where temperatures were in the low teens. So the room definitely keeps some heat in, but obviously not enough for the LEDs in the tent to keep the tent warm, hence the heater. The tent, according to my thermometer, was 70-78 degrees over the 36 hour span of the polar vortex. This was with no venting.

Here is my setup:

Door from outside to uninsulated under-porch room.


Here is a view in the tent:


View with LEDS on and extra LED hanging:


And one of the two seedlings popped through:


So, here's my concern/questions:

I have a set-up unlike any I've seen here. I am planning on running a 190 CFM vent fan from my basement through the wall to the tent for air exchange purposes. The will provide positive pressure, and is not something I have seen anyone discuss. I am doing it this way to keep as much heated air in the tent as possible. Is this a bad idea? Will this cause my heater to run constantly, as the air in my basement is 65 degrees, and I will also lose heat as the duct work will be about 7 feet, 6 of which are uninsulated in the room? Will the humidity in the room drop or climb if I'm adding cooler air to the tent, which has pretty dry air as the heater seems to dry out rooms (when I use it in a regular room so I'm assuming it does the same in the tent)?

Do you think this setup will also work in the summer? I am hoping to be able to grow year-round in the tent.

Thanks for any comments/help! I can take pictures as needed.

You're going to need more light for those two plants.

You should consider some insulation which would help both in winter and summer. You could build a box around the tent or insulate the inside walls of the shed with Styrofoam insulation. Cheap, easy to work with and will keep your temps more reasonable imo, reduce your heating and cooling costs in summer.

GroErr said:

You should consider some insulation which would help both in winter and summer. You could build a box around the tent or insulate the inside walls of the shed with Styrofoam insulation. Cheap, easy to work with and will keep your temps more reasonable imo, reduce your heating and cooling costs in summer.

Click to expand...

I had not thought of that option. I could go buy the insulation boards and create a shell to go around the tent. This is great idea.

Hey Tyleb173rd: is it the size or wattage of my lights thats the issue? Again, pretty n00b to all this. Should I add CFLs, get a larger LED panel?

Mexojay said:

I had not thought of that option. I could go buy the insulation boards and create a shell to go around the tent. This is great idea.

Hey Tyleb173rd: is it the size or wattage of my lights thats the issue? Again, pretty n00b to all this. Should I add CFLs, get a larger LED panel?

Click to expand...

Cheap way to manage temps and reduce your electric bills. I insulated my cold cellar and turned it into a flower room. The insulation helps both in summer and winter. Cheers.

Mexojay said:

I had not thought of that option. I could go buy the insulation boards and create a shell to go around the tent. This is great idea.

Hey Tyleb173rd: is it the size or wattage of my lights thats the issue? Again, pretty n00b to all this. Should I add CFLs, get a larger LED panel?

Click to expand...

I'd say both. Also, insulating will help you more during winter than summer. When I grew in a tent, in the garage, I shut the growing down for the summer. It's so much easier and cheaper battling the cold then the heat IMO. Good luck sir.

Update: I hooked up a filter to my vent fan and I'm sucking through the filter, into the duct, through the room and into the tent. I have the fan set so it's at about 90cfm. The temperature has been very stable (72-77) in the tent, and every time I check the heater isn't going. And we've had teens at night again. The room that houses the tent it isn't getting below 35. So I think supplementing the tent with 65 degree, filtered basement air is helping the tent stay at the correct temp. However, the RH doesn't get above 25%. Is this too dry?

Both plants look excellent. They aren't stretching, which would lead me to believe they're getting enough light. I still want to add more light but am not sure how to. Should I buy another led panel or I should I get some kind of HID ballast?

Mexojay said:

Update: I hooked up a filter to my vent fan and I'm sucking through the filter, into the duct, through the room and into the tent. I have the fan set so it's at about 90cfm. The temperature has been very stable (72-77) in the tent, and every time I check the heater isn't going. And we've had teens at night again. The room that houses the tent it isn't getting below 35. So I think supplementing the tent with 65 degree, filtered basement air is helping the tent stay at the correct temp. However, the RH doesn't get above 25%. Is this too dry?

Both plants look excellent. They aren't stretching, which would lead me to believe they're getting enough light. I still want to add more light but am not sure how to. Should I buy another led panel or I should I get some kind of HID ballast?

Click to expand...

That's not bad at all if you haven't done any insulating yet. RH is a bit low but not going to hurt anything if it stays above 25. You may want to consider hps for the winter, then look at LED for the summer to help keep temps in check.

Mexojay said:

Update: I hooked up a filter to my vent fan and I'm sucking through the filter, into the duct, through the room and into the tent. I have the fan set so it's at about 90cfm. The temperature has been very stable (72-77) in the tent, and every time I check the heater isn't going. And we've had teens at night again. The room that houses the tent it isn't getting below 35. So I think supplementing the tent with 65 degree, filtered basement air is helping the tent stay at the correct temp. However, the RH doesn't get above 25%. Is this too dry?

Both plants look excellent. They aren't stretching, which would lead me to believe they're getting enough light. I still want to add more light but am not sure how to. Should I buy another led panel or I should I get some kind of HID ballast?

Click to expand...

if ya lose power for a few hrs,looks like u might freeze up some thing to think about.do it right the first time

I have an auto-start generator for the house, so I'm not worried about power failures. We lose power a lot so I've had that setup for a while now.

I have not insulated the tent yet. I hope to do it this weekend. That should really cut down on the heater use.

As I go, will the plants provide moisture naturally to the air when they get larger, bringing up the RH?

Can you recommend an HPS light/ballast for a 4x3.5x5' tent?

I wanted to update the thread. The grow tent/room seems to be working very well. The space heater doesn't seem to run very often (electric bill only went up 3%), as the room the tent is in stays at least 40F even when its really cold out (and I haven't even insulated the tent). I have fresh 60 degree air coming in from the inside, and two 300W LEDs for lighting. The tent stays 72-78 with the auto switch hooked up to the space heater. Humidity does get low when the pots get dry, but that doesn't seem to be a big issue. My two plants, about two months old. I planted them into 5-gallon pots right away (mistake), and they looked like they were gonna die. Have since transplanted from 5-gallon to solo cups, then to 1 gallon where they currently reside. They are small for 2 months as the first moth they effectively didn't grow.

Take a couple big bowls or square Pyrex dishes and fill with water, then put in your tent.

Unless my hygrometer Is no good, it worked for me.