Hi Dandrew, It all depends what you're looking at growing (yield and flowering time). A good, conservative approximation with continuous harvest would be 1.5 ounces a plant every 8 weeks. You want 8 ounces every 8 weeks, so 6 plants will cover that. If you're growing something that you can harvest every 6 weeks, 4 plants will take care of your needs. I generally pull 2-2.5 ounces (dried and cured) off each white widow plant, so if you're looking at a strain with a relative yield like WW and are utilizing nutes to their potential, that's a good standard. For lighting, if you have a nice Mylared or flat white area, you could get away using a 250W HPS (DEFINITELY enough for 4 plants). If you want the extra edge, boost that to a 400 and you'll be rocking. Hope this helps out. Take care. Mak~
