Master Nursery® Bumper Crop® Organic Soil Builder is a soil building blend of manure and high organic nutrient content of shellfish compost, dark, rich earthworm castings (adds minerals and biology), kelp, peat, aged bark, and lobster – inoculated with endo and ecto mycorrhizal fungi to improve root function. The lobster body provides a lot of Nitrogen, and the shells breakdown to release a lot of calcium, the #1 ingredient that plants need. Bumper Crop® Soil Builder is an all-purpose, pre-fertilized planting and garden soil amendment. This product excels as a nutrient rich top dressing and mulch. OMRI Listed for organic use. This formula will help protect plant roots from soil erosion and temperature extremes. It will also help retain soil moisture.