How can I keep the temperature good? It gets warm in summer, and pretty cold in winter. No insulation in barn... I can make the grow box by myself.
A heater will work fine for the winter. As far as for summer as long as it doesn't get above 95 degrees in the barn you'll be good. If it does invest in one those window air conditioner units if the barn has windows and cool down the whole barn if you can. Also make sure there's plenty of air circulation with fans and such to make sure no dust gets in the grow.
Yea, the barn is pretty open..walls, but no doors. How do should I put lights and filtration in it? The box will be around 6’x8’x9’. This is something very new to me...