jerejoy,
My boy doesn't have soft poop like he did previously when he as drinking only fm. Since he started on solids, his poop is firm but still can be pressed easily. i.e. it's soft to press. It shouldn't come out like little round marbles. If it does, then it's a sign of constipation.
Currently, everyday he takes 1x plum puree and 2x papaya puree. Have also introduced blended leafy vegetables and corn - hopefully this helps him to poop more easily. Will monitor and see how it goes.