6. Oyster mushrooms
Estimated price per pound: $7
While all mushrooms are convenient as specialty crops – given that they can be grown indoors – the most productive choice is the Oyster Mushroom. In fact, on a surface of one square foot you can grow up to 25 pounds of these mushrooms and given their sales price per pound, that can amount to $17,500 in one single medium sized harvest. The fresh gourmet mushrooms are also in high demand at every farmers market.