Should I use MH at veg and HPS during flowering?

[Dutch Pimp]

A Metal Halide bulb in the 5000k-6500K.. kelvin, color temp range will reduce the stretching of plants.
A HPS bulb will let the plants stretch more, but is fine for vegging too. Most HPS bulbs are in the 2000k-2700k...kelvin, color temp range.

I've used both... use, whatever is easiest, for your situation...the KISS principle...:thumbsup:

I use 6500k High Output T-5's, now...for vegging