Pacific Pearl Pure Ground Oyster Shell Flour Supplement for Plant Nutrition - Nature's Best Calcium. Trusted since1906, Pacific Pearl has been a leading provider of crushed oyster shells for the agricultural industry for over a century, guaranteeing superior quality. We offer the purest form of oyster shell calcium, unmatched in the market for its quality and effectiveness. Environmentally conscious choice, sustainably sourced, and ensuring minimal impact. Suitable for all plants. Effortless application. Guaranteed Minimum Calcium Carbonate 96.0%. Organic and OMRI-listed. Made in the USA - our oyster shell is carefully harvested and processed in the USA, ensuring the highest quality and purity.SUGGESTED APPLICATION VEGETABLE GARDENS & FLOWER BEDS: Use 4-5 lbs. per 20 ft row. For small annuals & perennials, use 1 tbsp per plant when planting. Mix into soil. Roses and large flowers may require 1-3 lbs. depending on the size & condition of the plant. LAWNS: New Lawns: Apply 10 lbs. per 100 sq ft. before seeding or sodding. Existing Lawns: Apply 10 lbs. per 100 sq ft. for initial application. Follow up with 4-6 lbs. per 100 sq ft. OUTDOOR CONTAINERS: New Plantings: mix 1-2 tbsp per gallon of soil. Established Plants: add 1-2 tbsp per gallon to the soil surface every other month during the growing season. TREES & SHRUBS: Spread 1 lb. per 1" of trunk diameter around the base, extending outwards to the drip line. HOUSEPLANTS: Use 1 tbsp per 6-inch pot. POTTING SOILS: Use 1/4 - 1/2 lb. per cubic foot of mixture. COMPOST: Apply 10 lbs. per cubic yard. Or 1-2 lbs. per wheelbarrow load of clippings, leaves, garden debris, or manure. For best results, apply in Spring and Fall. Apply to top of soil or mix in. Use regular watering methods after planting or spreading. Can be applied by spreader or by hand. GUARANTEED ANALYSIS: Calcium (Ca)...................................36% Calcium Carbonate Equivalent.......92% DERIVED FROM: Ground Oyster Shell Marl