I run an urban farm on property I own, where do I account for interest on my mortgage, taxes on land used for farming, and rent I charge myself on my schedule C?

You'll actually enter it on a Schedule F, if it's for a farm.

To enter it in Turbo Tax:

1.  Click Federal on the left-hand side menu.

2.  Click Income & Expenses across the top.

3.  Scroll down to Rentals, Royalties, and Farm and click Show more.

4.  Click Start or Revisit by Farm Income and Farm Rental.

Go through the interview to enter all your income, expenses, and assets.