standnplant.com - I have seen various forms of this same tool but I really feel this one is the best value for your money. It does work with seeds, you would just have to watch how deep you place the tool so they weren’t planted too deep. Basically if it fits down the barrel, you can plant it!
Good question. I don’t have anything ready in soil blocks right now or I would run out and try but I don’t foresee any issues with small blocks if you’ve got nice healthy transplants. I start my sunflowers in 128 trays and haven’t had any issues with the smaller plug. Hope this helps!
