5x6x6 plastic shed

ok i asked yesterday about a 4x4x6 tent but i was curious i have a 5x6x6 plastic shed on the side of my house? would the heat be to much for this shed?its actually pretty sturdy.or would i be better off just using a tent?

if you sealed it well and it was insulated, and have a portable a/c, i could make a killer enviorment out of it with what you would spend on the tent lol, well would be about same price but more room for more plants =)

how would u recomend insulating it?