Help with simple Plant deficiency...Noob grower.

Hi everyone just recently started my first grow about 40 days ago unfortunately I ran into some problems and am looking for advisement. My set up is small 30'' x 30' x 28'' stealth grow box. I have 5 100w and 1 150w cfl light bulbs. A 12v 120mm intake fan, exhaust port and regular fan inside to keep good air circulation. Currently i have three plants growing, one is a bag seed approximately 40 days old, the other two are auto flowers: berry ryder and barney's farm purple cheese. All three plants seem really small for over 30 days. The two auto flowers especially, although they are not showing any signs of deficiencies. The soil they are planted in is some organic quality soil from my local store and i started FF Grow big nutes a little after each plant was 3 weeks old. I use 1/4 strength and give them nutes every other watering. I water about once a day but make sure the first few inches of soil are dry. Still the bag seed which is 40 days from sprout has yellowing, curling up leaves, and although the two others are showing no sign of deficiencies they are very small for their age. I use distilled water to water the plants, and the soil ph is right around 6.4.The waters ph is about 6.8, so i do not think it is ph problems. The bag seed was in a small 4'' by 4'' pot to start out but i just recently transplanted it to a 1 gallon and changed the soil to FF ocean forest because i thought it may have been root bound. Unfortunately my bag seed plant is still showing signs of deficiencies and the others are growing very slowly, but i can not figure out why...please help

Here are some pictures of my plants:


Bag seed before transplant, 34 days old:





Bag seed, after transplant, 40 days old:













Auto flowers, first one is berry ryder already starting to flower, second is purple cheese which I lst, both in one gallon pots: