Yellow leaves

This is my first grow and I'm not sure how to fix this problem. The plant seems to be growing very slow and the bottom set of leaves are yellowing and burnt on the tips. The average Humidity is about 50% and the temperature is are 72. I use organic potting soil and general organics nutrients. I have a 400 w hps bulb around 2 and a half feet away from it.

Sounds like you are burning them, flush a few gallons of water through each plant then give them a few days and see what they do. I recommend flushing with R/O water if you have the means.
Post pics, that always helps.

Stop giving your plants nutrients.

Yeah if you're running with potting soil you do not have to give nutes the same way as in coco coir or other external nutrient systems. Agree with the flush, but easy on the Reverse Osmosis water. It will leach out nutes from the plant. Maybe one hit of that, then flush. Then light water for a few days after flushing.

Sounds like nute burn, Flush em and stop feeding them so much. Pics would also help..

they can be 12" away from your bulb and be fine. Mine are close to ten inches away, and growing every day. you're losing a lot of light being that far away from a 400w