Espoma Organic Lightning Lime is no ordinary limestone. A 30 lb bag of Lightning Lime covers up to 5,000 square feet. That is because our lime is treated with a natural humic acid that helps the soil and plants convert calcium into an immediately available form. In addition, Lightning Lime can work in just 6 to 8 weeks instead of the up to 14 months other lime products require. Lightning Lime is also less dusty than traditional lime products and is approved for organic gardening.