Well that 42 watt outputs 2600 lumens, if you want a good grow you need 10,000 lumens.

So four 42 watt bulbs will be good making it more than 10,000 lumens, but you would have to get four 42watt soft white(2700k) bulbs for flowering and four 42 watt daylight(6500k) bulbs for vegetation.

The good things about soft white(2700k) bulbs you can use them for vegetation and flowering, but daylight(6500k) bulbs would be the best.

soft white(2700k) bulbs = best for vegetation

daylight(6500k) bulbs = good for vegetation, best for flowering



I mean soft whites instead of cool whites. On my post above.