Berries and composting

Ultracompost is the best compost; once supercompost is ready to harvest, add volcanic ash (mined on Fossil Island) to the opened compost bin (after produce has matured into supercompost) to convert the whole bin to ultracompost. The Farming Guild has a big compost bin which takes 50 volcanic ashes to convert, a single supercompost bucket needs 2 volcanic ash to become ultracompost--converting whole bins is more effective. If you accidentally take a supercompost from the bin, you can still add volcanic ash to the bin so the rest is ultracompost.

Bushes, once grown, continue to yield berries which you can pick repeatedly. This is a good way to get super compostable produce, for example white berries and jangerberries.