🐚 Oyster Shell Flour – 1 LB Premium Calcium & pH Buffer for Worm Bins, Mushrooms & Gardens

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Give your soil, mushrooms, and worm bins the boost they deserve with our Lumbri Worms & Garden Premium Oyster Shell Flour. This finely-milled calcium supplement is a must-have for growers who actually care about consistency and balance — not chaos in the bin.

Made from pure, natural oyster shells, this flour acts as a long-lasting pH buffer, helping maintain stable conditions in worm bins, improving substrate structure for mushrooms, and reinforcing soil health in gardens and raised beds.

This isn’t gritty crushed shell… this is true flour — ultra-fine, fast-reacting, and perfect for growers who want predictable results.

Why Growers Love It

🔧 Buffers pH naturally – Keeps worm bins from going acidic and prevents “sour bin syndrome.”

🪱 Supports healthy digestion in worms – Works as a micro-grit to help worms break down food faster & produce richer castings.

🍄 Perfect for mushroom substrate – Stabilizes pH and improves mycelium colonization.

🌱 Strengthens soil structure – Adds bio-available calcium for tomatoes, peppers, leafy greens & heavy feeders.

🌿 Long-lasting and slow-release – Doesn’t wash out quickly like other amend­ments.

How to Use

For Worm Bins:

Sprinkle 1–2 teaspoons per feeding or 1–2 tablespoons weekly for larger systems.

For Mushroom Substrate:

Add 1–2% of total dry weight (about 1–2 tablespoons per 5–10 lbs of substrate).

For Gardens & Pots:

Mix 1–2 tablespoons per gallon of soil, or ½–1 cup per cubic foot of mix.

Ingredients

100% pure oyster shell flour

No fillers. No additives. Just clean, consistent calcium.

Weight

1 lb (resealable matte black stand-up pouch)