CMH vs QB in a cooler environment: advice requested

Rocket Soul

Well-Known Member
Hi all!

I'm setting up for a grow in a relatively cool basement, around 55-65 degrees F, in a 2x4 tent.

I had been planning on buying the HLG 260 QB kit, but I'm concerned about maintaining enough heat in a tent. As an alternative, I was considering a 315 CMH set-up, which I assume would generate more heat, probably to my benefit in the cooler environment.

I don't want to mess around with supplemental heat, for cost and safety concern reasons, if possible.

My question: In a cooler 55-65 degree environment, which light would maintain the right temperature environment in a 2x4 tent, the QB or the CMH?
CMH with batwing reflectors give a very nice 4x2 spread. The added infrared helps with transpiration but wont get your plants as hot as hps. If you wont have good environmental controls id rec CMH over led. But maybe a bit bigger than 4" outtake.
 

buckyshimp

Member
I'm really appreciative to you guys for your help! I'm going to build a box in the basement based on the space available. The advantages, I hope/assume, include that the foam will help insulate and hold temps during the cooler 55F nights (I could maybe employ a small heater connected to a thermostat if needed but I'm hoping to avoid this).

Are 1" thick foil foam boards like these from lowes the right idea, with some foil insulation tape to connect it all? (sorry, not sure if I can link to a store):
Johns Manville (Common: 1-in x 4-ft x 8-ft; Actual: 1-in x 4-ft x 8-ft) AP Foil R- 6 Faced Polyisocyanurate Foam Board Insulation
 

Aqua Man

Well-Known Member
The reason I use the metal tape is only for the seal inside and it's stay in the humidity and heat. If you are taping it outside any tape that sticks well will work.
 

buckyshimp

Member
Ok, great.

Is there a must-have tool for this process? Someone mentioned a hot knife, but that seems like a luxury more than a must-have, correct?
 

Aqua Man

Well-Known Member
Ok, great.

Is there a must-have tool for this process? Someone mentioned a hot knife, but that seems like a luxury more than a must-have, correct?
I just use an Olfa with a nice new blade and a straight edge. Measure twice cut one always saved me some materials over the years lol. Hot knife would be the cats ass though.
 

TintEastwood

Well-Known Member
I just use an Olfa with a nice new blade and a straight edge. Measure twice cut one always saved me some materials over the years lol. Hot knife would be the cats ass though.
I still use this method.
Heat up the end of a hacksaw blade with a propane torch. Carve holes and cut to size ezpz. It does take some practice. How hot to get the blade....how long it stays hot. Too hot not good....you will learn in practice.
Use long ruler/wood to guide for more precision.

Note: Melting the foam this causes fumes.....fumes that I consider toxic.
Plan accordingly. Not inside.


I use these... about $17 per sheet usa.
https://www.homedepot.com/p/R-Tech-1-1-2-in-x-4-ft-x-8-ft-R-5-78-Rigid-Foam-Insulation-320817/202532855

There are other foam sheeting types...possible higher R value.

Grow on!!
 
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