Ok sharp if he is worried about the cotyledons then its is probably a seedling. If it is the tips its probably overfertilization. Seedlings use very little water. I'' feed it a light fertilizer weekly and water the other times about 2-4 times a day. I mix organic fertlizers in the soil and that carries them for months. Leave them alone. Water them makes sure they are ok and leave them alone. They will grow and be fine.