First of all I give Fast Buds a 10 on the strain and give myself a 5 for my mistakes during the grow. I did alot of mistake, but got my harvest. Thx FastBuds and all who followed me:)
What types of lights are you using? Your plants are very small for 4 weeks old and have stretched a lot. Are you checking the PH of your water ? It looks like the leaves are yellowing from either lack of nutrients or wrong PH.
I’m still learning myself. Look at my diary for similar 4 weeks age (under week 5)