When reusing containers be sure to properly sterilize them first.
Whether you recycle nursery containers or reuse those from last year’s garden, make sure all are properly sterilized before planting seeds. Wash out all remnants of soil or organic matter sticking to the sides. Then dip each clean container into a bucket containing a 10% bleach solution to kill any remnants of prior diseases that could attack your seedlings. Wait until your clean, sterilized pots dry before adding Black Gold Seedling Mix for a safe, sterile germination bed for your seeds.