2 Week Old Constipated

My baby pooped once yesterday and just finally pooped again (about 22 hours later). It is definitely constipation poop. Nothing was "solid", but it was definitely clay like and he was grunting and screaming/crying every time while trying to poop. Will he be cured of this constipation now or should I give him some apple juice? I do know the amount to give. He is on soy formula due to a medical condition, so I know that soy can cause the constipation.