How often should a five month old poop?

Varies. Baby food will usually alter the stooling pattern based on the items involved.Some items;applesauce, rice cerreal, bananas tend to slow baby down while peaches, pears, prunes speed them up. If baby is skipping days a reduction in the volume of the solids can increase stooling. Solids this young are meant to teach baby to handle solid foods, not replace the nutrition in breast of formula.