Listen to Zandor. NL's were my first hydro. 4 oz's off a 400watt HPS light. 6 x 6 is a good space I would get a 1000 watt and 6 to 12 plants I'm learning inside you don't grow tree's, you grow more small ones with big buds on them. The light can get to them . When you grow tree's your top light is only growing the top 1/3rd of the plant. Check out others grows. Mine are week 7 flowering orange bud. I'm learning too, if Zandor gives you advice take it to the bank.