Hi mate, 6 plants seems a lot for a 2x2. I grow one in that space and at a push maybe 2 autos but 6 would be impossible. Is 300W the true output of the light, you're looking for about 30W/square foot but 100W is minimum for a 2x2. Mine is 110W. Any higher and I would struggle with high temps. I hope this helps....good luck and happy growing.