1st time grower

I'm just starting my first grow. I'm going to use a 400 MH for the veg, and a 400 HPS for the flowering. How far should they be away from the plants. The humididty is @ 27%, I know that's low I'm going to get humidifer. But does it matter if it's warm mist or cool mist. Any suggestions from any1 would be greatly appreciated.. Thanx

use your hand/wrist to determine how hot it is, get the light as close as possible without it being uncomfortable to the plants/your wrist. if you have an air cooled reflector you can get them like 5-8 inches away or even closer. otherwise prolly a foot or so, but its all about heat! use your hand to see how close you can get them.

I saw a chart that showed a 400W HPS from 12" away is similar to power of sun in a tropical climate....

Thanx. I'm growing my plants in soil, what is the best kind of fertilizer. When should I 1st feed them and how often?