Very First Grow

Rough start of week 4, The Auto ultimate seemed very droopy at the start of day 21 and the first true leaves are showing some yellowing, I tested my soil and water PH, both seem fine, I think it may have been underwatering, My water frequency seemed alright, but I dont think I fully saturated my medium and let the centers of the pot dry out. I promptly watered untill I got runoff and a day later both plants seem to have really perked up, I'm afraid I may have stunted the Ultimate a little, she's still growing and very bushy though, both plants smell like a fresh bush of nettles and seem very firm. I think Im going to be less paranoid about overwatering, the plants are in fabric pots and get plenty of airflow, if anyone has more tips on how to foolproof the whole watering, I would really appreciate it. Its by far the most stressful part, since im never sure when enough is enough and not too much or too little