I am starting to prepare supplies for the garden. I would like to reuse my plastic seedling trays from last year. What is the best way to clean these for seedling use? Boiling water, warm soapy water, diluted bleach solution?
Unless you had disease problems last year, there is no need to clean the seedling trays at all. I just dump last year's remnants out and reuse trays year after year, and I've never had any problems.