8x8 Grow Room, will 2 inch foam be enough?

A question of a fellow grower:
Quick question, i want to convert a room in my garage/barn (not insulated or heated) to a grow room. room is 8 x 8 about 7 ft high.

I plan on insulating with foam board and adding a small heater and led lights.

I am north of 49th parallel so it gets cold.

I wont start growing until march.

You think 2 inch foam on all walls and ceiling will be enough?

Also when warm weather arrives I plan on leaving the door open (its an inside room) for ventilation.

Any thoughts?

Oh, will grow in 5 gallon pails in new dirt spiked with nutrients.


I think you should be able to make that work in March as long as you don’t have a real cold snap for some odd reason that lasts a month. 8x8=64 sqft =3200Watts of light to light area minimum + a space heater…I’m guess that and if you insulate well you should be fine, if not add a heater :wink:

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@Donaldj I recall you have a up north where it’s wicked cold grow shed?

I think you’ll be fine using two inch board
Just make sure you seal the edges well maybe even use spray foam to seal it
Also having either temp or speed control of your exhaust fans will be helpful to control temps

I would also suggest you run light at night when temps will be the coldest

I use a oil filled heater in my grow room
Which works well for me I’m located in my basement I have one similar to this one just older haha



It sounds like you need the foam on the floor too. If the ground is too cold the roots will have a hard time


@basementstealth that’s a good point

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