Soil Blocking

Black plastic seed growing trays have warnings for cancer and reproductive harm. The seed trays are made of recycled polyethylene terephthalate with the California proposition 65 warning. While the warning label didn’t outline the compound of concern, I suspect it’s antimony trioxide, which plants can absorb. Rather than continually contributing to extra plastic waste that can pollute your water and soil, I like using clay, soil blocking, charred wood, egg cartons, and milk containers. 

A soil blocker is a great way to avoid relying on individual plastic growing trays and improve the hardiness of your crops when you transplant them. I’ve been experimenting with a soil blocker and found it works best with a blend of top soil and garden soil. You have to make the soil extremely moist but avoid over compacting it for the soil to hold together. You can then sprinkle the same soil on top after sowing the seeds into the little holes. When you release the soil blocks, be sure to spread them out to ensure air flow. You can then easily water the blocks from the base.