BEST QUALITY! MICRO SOIL BLOCKING BLEND with Organic Compost and Greensand - 8 Dry Quart Bag Specially Formulated For Micro (1" or less) Soil Blockers. Developed and tested to promote excellent root and stem development for your new seedlings. Natural and Organic Soilless Seed Germination Mix in 2 mil poly bag. Made from Coco coir, sphagnum peat moss, organic compost, pumice, and greensand. Follow the manufacturer's instructions for making soil blocks.