Calcium Carbonate (Agricultural Lime) for Mushroom Cultivation

Finely milled calcium carbonate (CaCO₃) is a mild, long‑lasting pH buffer that keeps substrates and casing layers in the optimal 6–7 range without the caustic bite of hydrated lime. It also adds calcium that supports firm, healthy fruit bodies.

Why Use Calcium Carbonate?

• Raises and stabilises pH gradually – no risk of overshooting.
• Improves texture and drainage in peat or coco based casings.
• Adds calcium, an essential trace mineral for cell wall strength.
• Food grade, dust reduced and free of chemical binders.

Recommended Rates

• Casing mixes: 3 % of dry weight (≈ 30 g per kg dry casing).
• PF Tek cakes: 1 tsp per 2 cups vermiculite mix (≈ 2 % by volume).
• Bulk substrates: 1 % of dry weight if extra buffering is needed.

Blend thoroughly with dry ingredients or dissolve in the hydration water for even distribution.

Pack Size

1 kg resealable pouch. Store sealed and dry; calcium carbonate is stable indefinitely.

Basic Use

1. Measure the required amount.
2. Mix into the dry substrate or casing until evenly dispersed.
3. Hydrate, then pasteurise or sterilise as usual.

Tips

• Combine with gypsum (50/50 mix) for the classic “50/50+” casing recipe.
• Do not substitute for hydrated lime in cold‑water pasteurisation – it is too mild for that purpose.
• Wear a dust mask when handling fine powders.

Safety

Inert but dusty – avoid inhalation and keep out of reach of children and pets.