Thinking about "foaming" my naked shed

I live in the south and our winters are pretty mild. Last season I had a 4' x 4' x 8' grow box with a 400 watt HPS that kept my plants from dying. Since then my wife caught me and didn't want me growing (her idea of me growing was one potted plant, not the small factory I had) but I have converted the shed into my "man cave" and I have some other plants I have in there (absorb all my pot smoke). So not only do I want the thing warm for me but I also want to keep whatever plants I do have in there alive.

Has anyone tried spray foam insulation? Right now my shed is just 2x4s, plywood and cheap siding. I want to pull everything out and apply the foam just like they do on new construction. I might be able to get the stuff pretty cheap if I buy it in bulk but I wanted to know if anyone had ever tried it before I did it.

Spray foam is expensive - about $1.00 per board foot, so your shed would cost around $500 to spray with foam.

Use unfaced fiberglass, and cover with a white vinyl facer - it will be cheaper, and the white vinyl will give you a nice reflective surface for your lights.

You can spray foam on a small scale, with regular 'great-stuff'in spray-cans.
The foam you are talking about is a two component polyurethane foam, I believe, and it requires expensive equipment for the application. Not for the DIU.

Why can't you use styrofoam. Lowe's even sells it with reflective aluminum backing on it, in several thicknesses. Easy to work with - air and light tight.