I plan of growing 3 plants, is 600 watt lights that is dimmable too much? Or will they be fine under it. Or should i look at flourecents? And if you think i should get fluorescent keep in mind I'm growing only 3 maybe 4 plants also I'm short on cash for something under 50 dollars would be great for the 3 seedlings also do i need a oscillating fan or something like that for the seedling and should i grow the seedlings in my 2'7x4'11x6'7 grow tent or somewhere else. And can someone tell me something about the domes for seedlings. Any info you have would be great.
You should keep the light as far away as your setup allows and dim it as low as it goes. You need to slowly adjust your seedlings to light that powerful. EDIT: If you haven't purchased anything yet, then you'd get a far superior harvest with the HID lighting, but if you want to purchase fluorescent tubes for vegging those work great. Get some 5000k or 6500k temperature t5s to start out seedlings and clones and get them ready for the HID. The humidity dome you are speaking of is good if your setup is low humidity. Seedlings and cuttings need high humidity since they are developing roots still, so a dome is good if you're spot is too dry. Other ways to increase humidity is simple things like filling a bowl with water, and leaving a washcloth hanging half inside the bowl and half out. Personally, I just use solo cups for seedlings and take sandwich baggies and put them over the cups for humidity.
i put seedlings under my 600 watt hps alllll the time. or i did. now i have a smaller light. but when i did it i put them at minimum 28 inches away to start. and that was when i had no glass shield on the light.