{"product_id":"coastal-oyster-shell-flour","title":"Coastal Oyster Shell Flour – High-Calcium Natural Soil Amendment","description":"\u003cp\u003e\u003cb\u003eCoastal Oyster Shell Flour\u003c\/b\u003e is an all-natural, micronized source of coarse-to-fine calcium carbonate (CaCO₃) specifically processed for living soil, commercial crop production, and organic farm management. Sourced from high-purity, ocean-derived oyster shells, this premium soil builder delivers a sustained, multi-season release of plant-available calcium while gently raising and buffering soil pH over time.\u003c\/p\u003e\n\u003cp\u003eUnlike standard agricultural lime, Oyster Shell Flour breaks down slowly through biological activity, making it an ideal choice for long-term soil building, no-till beds, potting mixes, and high-demand crops like tomatoes, peppers, and brassicas. Available in individual bags up to full commercial bulk quantities.\u003c\/p\u003e\n\u003ch4\u003eKey Benefits\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eSustained Calcium Release:\u003c\/b\u003e Provides a steady, long-lasting supply of calcium (Ca) to strengthen plant cell walls, enhance root development, and prevent deficiency disorders like blossom end rot and tip burn.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eNatural pH Buffer:\u003c\/b\u003e Gently corrects acidic soils without the harsh, rapid pH spikes associated with synthetic hydrated lime or quicklime.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eMicrobial Support:\u003c\/b\u003e Biologically active soil microbes consume and process the ground chitin and calcium carbonate, fostering strong soil microbiology and improving overall soil structure.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eIdeal for Living Soil \u0026amp; Bulk Blending:\u003c\/b\u003e A foundational ingredient for custom soil mixing, Super Soil recipes, raised bed construction, and market garden prep.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003e100% Natural:\u003c\/b\u003e Ocean-sourced, chemical-free input suitable for sustainable, natural, and regenerative agriculture systems.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eProduct Format:\u003c\/b\u003e Fine Ground \/ Flour (~20–100 mesh blend)\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003ePrimary Nutrient:\u003c\/b\u003e Calcium (Ca) – Approx. 33% to 37%\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eChemical Composition:\u003c\/b\u003e Calcium Carbonate (CaCO₃)\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eSource Material:\u003c\/b\u003e Natural Ocean Oyster Shells\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eApplication Type:\u003c\/b\u003e Soil Amendment \/ Top-Dress \/ Soil Mix Additive\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eRecommended Application Rates\u003c\/h4\u003e\n\u003ch5\u003e1. Custom Soil Mixes \u0026amp; Potting Substrates\u003c\/h5\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eRate:\u003c\/b\u003e Mix \u003cb\u003e1 to 2 cups\u003c\/b\u003e per cubic foot of soil, or \u003cb\u003e5 to 10 lbs.\u003c\/b\u003e per cubic yard of bulk substrate.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eBest Practice:\u003c\/b\u003e Blend thoroughly with peat moss, coconut coir, compost, and aeration components prior to planting.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch5\u003e2. Raised Beds \u0026amp; Garden Plots\u003c\/h5\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eRate:\u003c\/b\u003e Broadcast \u003cb\u003e3 to 6 lbs\u003c\/b\u003e per 100 sq ft of bed area.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eBest Practice:\u003c\/b\u003e Lightly incorporate into the top 2–4 inches of soil in early spring or late fall.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch5\u003e3. Broad-Acre \u0026amp; Commercial Field Crops\u003c\/h5\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eRate:\u003c\/b\u003e Apply \u003cb\u003e250 to 500 lbs\u003c\/b\u003e per acre, depending on soil test recommendations and baseline soil pH.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eBest Practice:\u003c\/b\u003e Apply ahead of high-calcium demand crops or cover crops to allow microbial breakdown.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch5\u003e4. Top-Dressing \u0026amp; Living Soil Maintenance\u003c\/h5\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eRate:\u003c\/b\u003e Apply \u003cb\u003e1 tablespoon\u003c\/b\u003e per gallon of container size, or \u003cb\u003e½ cup\u003c\/b\u003e per plant canopy footprint every 4–6 weeks during active growth.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cb\u003eQ: What is the difference between Oyster Shell Flour and Oyster Shell Meal?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003eA: Oyster Shell Flour is ground into a fine mesh particle size compared to coarse shell meal. The finer flour consistency offers a significantly larger surface area, allowing soil microbes to process and unlock calcium more quickly and uniformly throughout the root zone.\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eQ: Will Coastal Oyster Shell Flour burn my plants?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003eA: No. Because it is a natural form of calcium carbonate with a low solubility rate, it releases slowly through biological activity and will not burn root systems or cause sudden alkaline spikes when applied at recommended rates.\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eQ: How does Oyster Shell Flour compare to agricultural limestone (calcite) or dolomite lime?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003eA: Oyster Shell Flour contains trace ocean minerals and breaks down at a rate that matches active biological soil systems. Unlike dolomite lime, which contains high levels of magnesium (Mg), Oyster Shell Flour supplies calcium without overloading soils that already have elevated magnesium levels.\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eQ: Can I use this product in hydroponic systems or sprayers?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003eA: No. Oyster Shell Flour is insoluble in water and intended strictly for soil, compost, and growing media amendments. It will settle in tanks and clog drip lines or spray nozzles.\u003c\/p\u003e","brand":"Core Industries, Inc.","offers":[{"title":"50 lbs. Bag","offer_id":50259037126893,"sku":"CBOSF-50","price":24.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1529\/6623\/files\/Coastal_Brand_Flour_50_lbs._Bag_-_1065x1420_cdfc7b38-8978-432a-a71a-dc025876e6b2.png?v=1784823521","url":"https:\/\/www.rockymountainbioag.com\/products\/coastal-oyster-shell-flour","provider":"Rocky Mountain BioAg","version":"1.0","type":"link"}