Latt- I keep a tally of every [bold-faced, capitalized], every expense I put into the 'sang patches. Remember that your profit -or loss- is calculated wether or not you make money. if you put that same 5k into the ground, what about the mileage to and from, the cost of tools/your time/soil suppliments/etc etc etc. IRS will ask you for your revenue figures, so be prepared to put something down for that as well; like zero for the first few years.
IMHO all investment is at risk.