Ceramic Metal Halide bulbs, at much lower wattage than HPS, but with more power than LED seems to be the immediate compromise. A 315w Phillips Ceramic MH will

Ceramic Metal Halide bulbs, at much lower wattage than HPS, but with more power than LED seems to be the immediate compromise. A 315w Phillips Ceramic MH will deliver a huge spectrum to the plants with less than half of the heat of a comparable 600w HPS/MH. The cost is getting very close to traditional HPS lights. LEDs do work, but they still use plenty of power, and are largely unproven. Try to find a greenhouse/grow store that stocks ANY led fixures. They have been cheap China crap for so long, that the better ones cost quite a bit of $.