Cubic Inserts are required to make a hole to accommodate the blocks made by the Micro 20 Soil Blocker. Each set contains four heavy-duty ¾-inch cubed plastic molds that will last for years. They come with four screws and four washers. Insert black cubes in the Mini 4 soil block maker, then fasten with screws and washers where the existing seed pins are.
Try out this Mother Earth News Seed Starting Recipe!