I Have A 600 Watt HPS....My Seeds Are Just About To Start Going Soon...When Should I Start With The 600 Watt? And Should I Use Maybe Something Not As Strong For When The Seedlings Are Just Starting?
You can use the hps as soon as you want to. Start off with the light about 2 feet above it and then gradually lower it. Just be sure that the temp stays right and if you notice burning raise the light back up.