How and When should i nut?

Hello guys, I'm new to growing and have a couple of questions. I'm growing indicas in a 2x3 grow box and they are going on 4 weeks old now. I'm using 2 75watt soft white light bulbs and 2 pc fans to keep them cool and to keep air circulating. The plants are in half gallon containers with Miracle Grow potting soil. One of my plants has been getting yellowing on the edges and from research I've done it's because I don't have nutrients going on them. I been giving them Just rain water and I guess they been getting a little nuts from the soil. I bought some plant food that has 6-7-8 NPK. My question is; How do I use the nuts? How do I mix? Do I mix it in the water? Do I give them the mix everyday? how exactly do I go about this? Please help!!!!

Hello you should try using daylight bulbs this early I think soft white is more for flowering..
plants look nice though

i think they are yelllow on the tips because your using miricale grow i hear/read its very hott in nutes and it looks like u didnt mix with any perlite

most nutes disovle in water its 1 tea spoon per gallon on label most likley but you need to do half the strength on the directions so you dont burn em then you can gradually move up to full strength 1/4 strength might be a good idea too

as to how to feed you give them nutes once a week or once ever other water ex. water with just water then once soil is dried out water with nutes mixed with water then once its dry reg. water again

on the new sprouts dont give them nutes yet you will burn those little ones..but like you said it might be a deff. just dont feet the little ones yet wait for them to grow nodes

ur npk is pretty off for veg state you have NPK 6-7-8 you want N and K to be higher than the P
and for flowering you want higher P than N and K

well hope i helped some Good luck

oh ya next time you might want to buy some perlite and mix it with your soil so your plants roots can get air and have a better chance to avoid root rought

For seedlings, nothing but water for the first 3 weeks or so.

After that:

WEEKLY, WEAKLY

Wet