how far from my 3 week old 10 inch tall plants should I have my 430 watt hps light bulb(normal sunsystems reflector)?
general rule is to put yar hand on top of the plant. Too hot for you, too hot for her. Given heat is no issue, ill say the closer is the best since lumens decrease drastically as you pull away the source. peace
also if you keep a fan blowing up at your light...pushing heat away from you baby girl you can have the light lower....is heat a problem in your spot?