when should i give seedlings in soil nutes

hi i have some seedlings in soil under a 600 watt for about 2 weeks a friend of mine said give em a light feed which ended up in brown tips yellow leaves i have left em alone and have given just straight plain water for about 2 weeks so so far they have had 2 feeds they are not very big as i think the nutes have stunted there growth from the shock of the nutes so i was thinking should i just plain water it for a wile till i see some new green growth ?

Yes you are correct. A seedling doesn't need any food till the cotyledon ( first set of leaves rounded) start to turn yellow. Then you can give them very little. Like 1/4 the recommended dose. Did you flush the seedling. Are they still getting worse?

yes i did flush with water and im given nothing but plain water now every 3-4 dayz

It would be useful to test the pH of your soil also. When your seedlings start taking full applications of nutrients you can adjust to avoid problems like lockout.