OK, so my seedlings are getting big about on their 3rd node of leaves and the roots re starting to reach the bottom of the pot. its time to move them to bigger pots. so i do... the next day the top leaves on 1 of the seedlings were yellow at the tips of the leaves. i need help on how to fix this problem... the ph in the soil is 6.3 so its not the ph.. idk if under watering or over watering causes yellow leaves? cuz thats what im thinking happened withthe new soil.. please help~!