MY First Grow-Chisel VS White Russian

Hi im 3weeks in growing from seed i have 4 Big Buddha Chisel plants & 4 serious seeds White Russain plants and all should be fem.

Just wanna now what People Think and if anyone can help!!!!!!!!!

im using coco coir and want to no when to pot them iv still got them in a prohibiter and using a 110w sum mate proagate light producing 8000 lumens im thinking of changing light soon to a 250CFL for the rest of the Veg grow then hps 400 or 600 for bud.

i also have one extractor fan pushing the warm air out and a 9inch desk fan circulating the air.

one down side at the moment im growing in a very small space but plants will be moved when buding to a grow tent

Oh yer some Of my plants leafs have gone yellow or burnt on the ends why is this?

so any advise let me no pls!!!!!!!!!!

Are you feeding any nutes? They look pretty young so go really easy with the nutes.

No nutes until the 3rd or 4th node, and then only minimal amount. Looking good, I would suggest 600w hps for 8 plants. Does your soil contain any ferts?

Yer Im feeding nutes i started with viyalink seedling feed for the first 2weeks now im using vitalink coco coir growth feed with vitalink biopuls and silicon+ PH lvl is around 5.8 -6.2 in the nut tank

but have a look at this pics one of the plants look like its dieing dnt no if its over watering or nut bun or what help me out pls