Hey there again my friend. If your plants are not burning then the light is not to close. If it doesnt get to hot for your hand after 30 seconds its fine. Although I think people keep their lights to close generally. If you have a HPS light and its anywhere around 24 inches its fine. The amount of resin or tight buds you get with a closer light is not that much. Keep it farther away and cover the plants better...dont worry about them burning this way either.
Yellowing of new growth is not good. Can you get a good pic. As far along as they are I would not think they would need any kind of extra nutes or bloom nutes necessarly yet. If ya have bloom nutes sure...switch to them but any yellowing I would say is not because they need any extra p or k yet. Its to soon.
Just let them get through the stretching period and re-evaluate their health. I usually wait till I see dime size flowers before I add any stimulators....I wait till I have nicle size button flowers then hit them with a tea of worm castings, bat guano, eathjuice catalist, Kelp meal and a little mollasas just to get the microbes going in the tea. Applying this tea to a plant that is not completly done stretching and has small button buds will stunt the growth and the leaves will twist and get thick. If you time your feedings with the plants metabolism you can effectivly rev up the pistol production...make the cola heads elongate bigger/taller/sooner and add more weight overall to your harvest. Again..understand I am a nooB grower but this is what I have noticed and the method that is working great for me. May not be for you with your setup as all rooms are different....
I am growing PPP again I do a perpetual grow with new plants flowering every 2-3 weeks. I have all nervana now..PPP, Blackjack, Super skunk, Ak48, Ice and Rasberry cough. Ice, Raspberry and PPP are in veg along with more aks and blackjacks.1 Balckjack...3 ak48...and 1 superskunk are in my flower room under the 1000 watter..all in different stages...all LST trained with between 4 and 6 colas each plant. I need to update my thread with new pics...I get lazy with this.
Gabe...what is your soil again? and nutes used?
Grasshopper