I'm not sure if I'm answering this one correctly, but I'll try!
My idea for the "Harvest" challenge is to go to a Farmers Market and buy your fruites and veggies for a week there, instead of getting them from the grocery store. (Or, if you can'at go to a Farmer's Market, then see if your grocery store has "local" produce-- if not, try buying Organic produce). This way, you are supporting local farmers who are harvesting plants.
What do you notice? Is the cost significantly higher? Does the food taste better? Do you feel better having supported your local community? Do you think you could plant a fruit or vegetable this sprint that you'd be able to harvest for your own dinner table?