They will, on passive and wandering enabled, produce and hold a Max of 100 organic polymer and 100 Achatina paste, if given some hours. Which means every day you log in you can collect a full amount. We have 12 of them and it really helps.
If you are considering breeding these, go slam your hand in a car door a few times. It will be much less painful. Literally one veggie cake per percent of growth....and it grows slow.. Digests roughly one point of food per second, so feed a cake about one for every 7 mins (during event boost) and it will gain one percent of growth.