Want to know the secret to harvesting more food without buying or planting seed every year? Instead of ripping out plants when they start to bolt or go to flower, plant heirloom or open-pollinated seeds (this is super important for this to work) and let some of them flower and go to seed. Especially plants like lettuce, dill, calendula, and cilantro that don't cross with other plants. Carrots can cross with Queen Anne's Lace but I've had fabulous success with them without taking any special meas