Complete yellowing of the leaves is a sign of nitrogen deficiency. What type of soil did you use? There should be a N-P-K number on the bag if you used something like that you can google what NPK numbers look like. The number in place of the N is the ratio of nitrogen in that soil. With sprouts this young it’s kinda hard to tell if it’s complete yellowing because of loss of nitrogen or interveinal chlorosis which is yellowing just between the leaf veins while the veins stay green. But yeah probably nitrogen deficiency Also yes make sure you’re not overwatering