I grew kale in self-watering plant boxes. Had a lot of aphids. Do I have to get rid of soil in boxes and wash out boxes before I plant this season?
If you have lost a plant due to an aphid infestation it is generally not a good idea to reuse the soil, but to start over with sterile soil and a pot and saucer that has been cleaned well. There is a possibility that aphids may have overwintered as eggs in that soil.