One organic way to kill off any lingering disease, after a crop has been pulled, is solarization. You prepare your raised beds for planting and then add drip tape. If you don’t want to use drip tape, you can just cover the beds after a good rain. You want the ground to be moist. Then, cover the beds with clear plastic, in the summer. This causes any diseases to bake, and die. Leave the plastic on for 4-6 weeks. The farmer who used rain water rather than drip tape kept his plastic on for nine weeks. The picture above shows our use of plastic on beds under high tunnels but this practice is also done outside.
Here, campers from Camp Kingfisher are pulling up a row of our dead sunflowers. Sunflowers are an example of a plant that is eerily beautiful in its dying days:
As are onion flowers: