OK, it has to be Spring,Summer,or Fall 1st. Now, buy 2 of 1 seed (ex-2 Corn seeds). Then, make a 3x3 plowed land for it. Stand in the middle square and spread both seeds(press Y to use a tool). Then, open the map and go to the mine. Carter might be there and he'll show you a tunnel to the Ore mine. Get all the Ore you can and do not ship it or move it from its square in your bag. Save all items until the end of the month and ship everything. You'll have plenty of money.
Why save it till the end of the month? Sorry to say but this "hint" doesn't seem very helpful at all, playing normally will get you the same amount of money.
