Home & Garden Garden How to Start Seeds Indoors By Tom Oder Writer Furman University. Tom Oder is a writer, editor, and communication expert who specializes in sustainability and the environment with a sweet spot for urban agriculture. our editorial process Twitter Twitter Tom Oder Updated May 31, 2017 Share Twitter Pinterest Email Home & Garden Planting Guides Indoor Gardening Urban Farms Insects Meet the soil blocker Tom Oder. An inexpensive, easy-to-use, hand-held tool called a soil blocker makes cubes of soil for starting seeds indoors. A soil blocker that makes four 2-inch cubes is ideal for home use. In the following series of photos, we present step-by-step instructions for how to start growing seeds using a soil blocker. (Text and photos: Tom Oder) Mix the soil Tom Oder. Step 1: Mix the soil with water into the consistency of oatmeal. Press blocker into soil Tom Oder. Step Two: Press the soil blocker into the mix until the mix fills the soil blocks. Wipe excess soil Tom Oder. Step Three: Wipe excess soil from the bottom of the soil blocker. Release soil into tray Tom Oder. Step Four: Release the soil into a tray (four rows of two-inch cubes fit perfectly into a 13-by-9-by-2-inch aluminum baking pan (available at box stores). Place seed in soil Tom Oder. Step Five: Place a seed in the indention the soil blocker makes in the top of the cube. Cover the seeds Tom Oder. Step Six: Cover the seeds with worm castings or potting soil. Mist the soil blocks Tom Oder. Step Seven: Mist the soil blocks and keep them damp. You can add water from the side of the blocks, but don't hit them with a stream of water. Place trays near window Tom Oder. Step Eight: Place the trays of soil blocks near a window that gets good light. Because air to the roots is not restricted by a plastic pot, seedlings will grow vigorously in the soil blocks as they await transfer to the outdoor garden.