it does but i found a hps keeps them very stocky and very close nodes, i had to veg my plant under the 600 watt hps and the nodes were all with in a 1/4 in of each other. if i had to choose to veg under MH or HPS i would do hps again. but i now veg under a single 200 watt cfl with great results as well as a lower bill
hps doesnt make them stretch either, its the light cysle and flowering that makes them stretch out so much. im not saying its the best to veg with but it works great and IMO better than MH. mabye once i start growing again i will do a comparison in veg with one MH and the other HPS