Garden Grade Gypsum Powder

Stop paying for "certified organic" labels on a mined mineral. Our Garden Grade Gypsum Powder offers the exact same chemical composition (Calcium Sulfate Dihydrate) relied upon by professional mushroom farms, at a fraction of the cost.

This is a pure, high-quality gypsum sourced for consistent performance. It is finely ground to disperse evenly through your substrate, ensuring every inch of your grow benefits from its buffering power. Whether you are mixing up a batch of CVG for Oysters or supplementing a manure blend for more advanced species, this gypsum delivers the results you need without the premium markup.

Key Benefits:

• Economical: Get more for your money. Perfect for high-volume growers.

• Finely Ground Texture: Mixes easily without clumping, even in dry mixes.

• High Purity: Free from synthetic additives, though not certified organic.

• Multi-Purpose: Ideal for bulk substrates, casing layers, and even soil composting.

Perfect For: CVG mixes (Coir, Vermiculite, Gypsum), straw supplementation, manure-based substrates, and improving soil structure for outdoor beds.

📝 Usage Guide: How to Use Garden Grade Gypsum in Substrates

Don't let the "Garden Grade" label fool you—the application is identical to the fancy stuff. Here is how to integrate it into your cultivation workflow.

1. The Standard Ratio

The "golden rule" of gypsum application is based on the dry weight of your base ingredient (coir, straw, sawdust, etc.).

• Standard Dosage: 5% of total dry substrate weight.

• Example: If you are using 650g of dry coir, you would add roughly 32-35g of gypsum.

2. Mixing Instructions by Substrate Type

Method A: Dry Mixing (For CVG & Manure Recipes)
This ensures the gypsum is evenly distributed throughout the substrate.

1. Combine Dry: In your mixing tote, combine your dry coir, vermiculite, and/or manure.

2. Add Gypsum: Sprinkle your measured gypsum (5% of dry weight) over the dry ingredients.

3. Mix: Use your hands or a trowel to thoroughly mix the powder into the dry material. You will see the mixture take on a slightly lighter, dusty appearance.

4. Hydrate: Add your boiling water (for pasteurization) as usual. The gypsum will activate and bind with the water, distributing the minerals throughout the substrate.

Method B: Wet Mixing (For Straw & Sawdust)
Use this method if you pasteurize your straw in hot water first.

1. Hydrate & Drain: Prepare your straw or sawdust to field capacity (damp but not dripping).

2. Sprinkle: While the substrate is still warm and spread out, sprinkle the gypsum powder evenly over the top.

3. Toss Thoroughly: Turn the substrate over several times, fluffing as you go. This ensures the gypsum coats the outside of the straw/hulls where the mycelium will first make contact.

3. Pro-Tips for Best Results

• Gypsum is NOT Lime: Remember that garden gypsum is different from garden lime (calcium carbonate). Lime is used for cold pasteurization (lime baths). Gypsum is a buffer and nutrient source. Do not substitute one for the other.

• Prevent Clumping: If your gypsum arrives slightly clumped due to humidity, simply sift it through a screen or whisk it before adding to your mix.

• Storage: Keep the bag in a dry place. While gypsum is a mineral and won't "go bad," moisture can cause it to harden into a brick, making it difficult to measure.