FYI, children make an amazing force multiplier for seed bombing. Not only do they love making them, adults are a LOT more forgiving if they deploy them in inappropriate places.

Also, if you present it correctly a lot of groups like the scouts would jump on helping. It's a fun activity for the kids, as well as great for the local environment. The kids involved can also be STRONGLY self motivated to make and deploy them in large numbers. They have several badges that this could be fitted towards getting.