Grow Q&A: Choosing Grow Lights • High Times
Dear Eric, You are smart to start with the 250-watt unit. Too many growers set themselves up for failure by buying a light too strong and hot for their space. 400-, 600- and 1000-watt HID lights create increasing amounts of heat buildup that must be addressed. Stepping up from Compact fluorescents to HID lights is a big step so act accordingly. You can also keep your CFL’s for growing seedlings into the vegetative stage and then switch to a HPS for flowering.
As for ballasts, most grow lights come as kits with a ballast, bulb and reflector all together. This is better than trying to mix and match a ballast to a separate bulb and reflector. Many people favor the new digital ballasts for heat reduction, but I’m not convinced yet that they don’t shorten the life of the bulbs substantially. Find a decent 250-watt HPS system specific for growing plants costing between $200 and $300 or so and you’ll be fine.