is mylar neccesary?

Im setting up my grow room and there is a definite need for reflection of the lights

i usually just use a white sheet but i cant use one in this situation

im having trouble finding some mylar can i use foil instead?

this may be a ridiculous question but it wont get too hot there and i dont need to use much

and how much does mylar usually run?

Foil creates hot spots which will burn your leaves. I don't think mylar is that much, but don't mind me... I have no hydro shop anywhere near me. You could just paint the walls white, it works just as well.

Theres a military surplus website called cheaperthandirt.com and they sell a package of three 50something inch by 80 something inch emergency blankets for like 10 bucks.

I have heard you can use those and that they will work almost as well.

Flat white paint works great,emergency blankets,hell iv'e even used the backs of spent party balloons just don't use foil it is no good save it for the kitchen.

If you can get co-extruded plastic has a black side and a white side if not I would just stick with flat white paint