Natural Gypsum (Calcium Sulphate – CaSO₄) | Mesh #16 Sifted | 500g

Agricultural-Grade Calcium Sulphate for Mushroom Cultivation, Soil Conditioning & Organic Growing

Not all gypsum is created equal.

Many growers unknowingly purchase coarse building gypsum or Plaster of Paris, only to end up with hard lumps, uneven mixing, or products containing additives never intended for biological cultivation.

At the SPeS Technical Services (STS) every batch is mechanically sifted through a Mesh #16 screen, producing a clean, uniform particle size that blends easily into grain spawn, mushroom substrates, composts and soils.

Natural Gypsum provides two essential plant nutrients—Calcium (Ca) and Sulphur (S)—while remaining virtually pH neutral, making it ideal wherever calcium supplementation is required without dramatically altering substrate chemistry.

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🛠 Technical Specifications

Product: Natural Agricultural Gypsum

Chemical Formula: CaSO₄

Common Name: Calcium Sulphate

Particle Size: Mesh #16 Precision Sifted

Net Weight: 500g

Packaging: Resealable Stand-Up Pouch

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🍄 Why Mushroom Growers Use Gypsum

Gypsum has been used in professional mushroom cultivation for decades.

Grain Spawn Preparation

Adding a small amount of gypsum during grain preparation helps keep sterilized grain loose and free-flowing, reducing kernel clumping and making spawn much easier to shake after colonisation.

Loose grain means:

• Better mycelial distribution
• Easier spawn expansion
• Faster recovery after shaking
• More consistent colonisation

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Bulk Mushroom Substrates

Gypsum is commonly incorporated into CVG and other bulk substrates as a source of Calcium and Sulphur while helping produce a more uniform substrate mix.

Ideal for:

• Coco Coir
• CVG Substrates
• Straw blends
• Hardwood sawdust mixes
• Compost-based substrates

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🌱 Soil & Garden Applications

Unlike agricultural lime, Gypsum supplies Calcium without significantly increasing soil pH.

It is commonly used to:

• Supply Calcium
• Supply Sulphur
• Improve heavy soil structure
• Support healthy root development
• Condition vegetable gardens
• Supplement raised beds

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✔ STS Precision Sifted

Unlike coarse agricultural gypsum, every batch is screened through a Mesh #16 sieve for a consistent particle size.

Benefits include:

• Easy mixing
• Uniform distribution
• Reduced clumping
• Professional-quality consistency

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⚠ Don’t Confuse Gypsum with Plaster of Paris

This product is Natural Agricultural Gypsum (Calcium Sulphate).

It is NOT:

• Plaster of Paris
• Construction plaster
• Setting plaster
• Cement additives
• Hardware store fillers

Only natural agricultural gypsum should be used in biological growing systems.

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📦 Package Includes

• 500 g Natural Gypsum (Calcium Sulphate)
• Mesh #16 Precision Sifted
• Packaged in a resealable stand-up pouch