When it comes to taking care of your monsters in Rune Factory 5, fodder is the most important item you need. When you get your first monster, you won’t need much as they only require a little bit of fodder per day. However, as you expand your farm and get more monsters to help you with the fieldwork, the demand for fodder skyrockets.
You can purchase fodder from the Serendipity General Store after completing Ryker’s “Build a Monster Barn” request, which becomes available after you clear the Whispering Woods. The seeds cost 30G each. Fodder takes four days to fully grow. Once it’s ready to be harvested, there will be a golden arrow above it, pointing down at it. Walk up to the Fodder and harvest it with the A button, just like you would with any other crop. Once you do this, rather than throwing in one pile of fodder at a time into your fodder bin, you’ll want to walk up to the bin and hit A. It’ll ask you if you want to throw in all of your fodder. Do this and all the fodder in your inventory will be thrown in there.
Unlike a majority of crops in the game, Fodder will continue to grow even after you harvest it. Just make sure to take good care of it so you can keep harvesting more Fodder without having to spend gold on getting more seeds.