one problem is the flea beetle: for example in 1876 flea beetles have destroyed half of the crops; many trials and experiments were needed to combat this problem.
Additionally, you needed to make sure that you have enough workers cultivating it.
Finally, your income was dependent on the prize you could sell it for, if the prize dropped, as in 1750s, it could happen that you would not even make ehough money to pay the loans.
