How to Use CVG Substrate for Mushrooms?

Understanding CVG Substrate for Mushroom Growing

CVG substrate—composed of Coco Coir, Vermiculite, and Gypsum—is one of the most effective and user-friendly substrates for cultivating mushrooms. It offers excellent water retention, aeration, and resistance to contamination, making it a favorite among both beginners and experienced mushroom cultivators. This guide will explore the composition, benefits, preparation process, and best practices for using CVG substrate to maximize your mushroom yields.

Breaking Down the Components of CVG Substrate

The success of CVG substrate comes from the synergy of its three core components: Coco Coir, Vermiculite, and Gypsum. Each plays a unique role in fostering healthy fungal growth.

1. Coco Coir

Derived from coconut husks, coco coir is a fibrous material known for its ability to retain moisture while providing a neutral pH environment. This makes it ideal for cultivating mushrooms that require a consistently humid substrate without excessive water saturation. Research supports its effectiveness as a growing medium due to its natural resistance to mold and its sustainable production (Carrasco & Preston, 2020).

2. Vermiculite

Vermiculite is a mineral that plays a critical role in aeration and moisture distribution within the substrate. Unlike perlite, which is sometimes used in other substrates, vermiculite holds more moisture while still promoting airflow. This balance prevents the substrate from becoming too compact, ensuring that the mycelium can expand efficiently.

3. Gypsum

Gypsum (calcium sulfate) is often overlooked but has crucial benefits in mushroom cultivation. It serves as a supplement by providing essential minerals that promote fungal metabolism and improve structural integrity (Tang & Zhou, 2017). Additionally, gypsum helps prevent the substrate from clumping together, ensuring even colonization.

Why Use CVG Substrate Over Other Mushroom Substrates?

Choosing the right substrate is fundamental to successful mushroom cultivation. Here's how CVG compares with other commonly used substrates:

Compared to Hardwood Substrates

• Best for: Wood-loving species like Shiitake, Reishi, and Maitake.
• Drawbacks: Hardwood requires lengthy preparation, often involving sterilization under high pressure. CVG, on the other hand, is easier to prepare and supports a broader range of mushrooms.

Compared to Manure-Based Substrates

• Best for: Some gourmet and medicinal mushrooms that thrive on nutrient-rich manure mixtures.
• Drawbacks: Manure is prone to bacterial contamination, produces strong odors, and requires strict pasteurization methods. CVG is virtually odor-free and simpler to handle while still supporting robust fungal growth.

Compared to Pure Coco Coir

While coco coir alone can serve as a growing medium, adding gypsum and vermiculite enhances colonization speed, aeration, and nutrient availability, leading to higher mushroom yields (Stamets, 2005).

Step-by-Step Guide to Preparing and Using CVG Substrate

A successful mushroom-growing process starts with proper substrate preparation. Follow these steps for optimal results:

1. Gathering Materials

You'll need:
✅ Brick of coco coir (650g)
✅ Vermiculite (4-5 cups)
✅ Gypsum (1-2 tablespoons)
✅ Water (approximately 4-5 liters)
✅ Large container or bucket with a lid

2. Hydration and Pasteurization of the Coco Coir

• Place the coco coir in a large bucket.
• Bring about 4 liters of water to a boil and pour it over the coir.
• Close the lid and let it sit for 30-60 minutes. This helps pasteurize the coir, reducing harmful bacteria or mold spores.
• After cooling down, break apart the coir until it reaches a fluffy texture.

3. Mixing in the Vermiculite and Gypsum

Once the coco coir is hydrated and cooled:

• Add vermiculite and mix thoroughly to distribute moisture evenly.
• Sprinkle gypsum evenly throughout the mixture, ensuring proper dispersion.

4. Checking for Field Capacity

Proper moisture is critical for mycelium colonization. To test:

• Squeeze a handful of the substrate—only a few drops of water should come out.
• If it drips excessively, mix in dry vermiculite to absorb excess moisture.

5. Allowing the Substrate to Cool Completely

• Never introduce mushroom spawn to a hot substrate, as heat may kill the mycelium.
• Once cooled, it's ready for inoculation.

Using CVG Substrate for Mushroom Cultivation

Spawning to Bulk

• Mix your fully colonized grain spawn (such as rye or millet) evenly into the CVG substrate.
• A common ratio is 1:2 (spawn to bulk), but experienced growers may use more spawn for faster colonization.

Incubation Period

• Store the inoculated substrate in a sterile container like a monotub or grow bag.
• Maintain a stable temperature of 70-75°F.
• Within 10-14 days, the substrate should be fully colonized with mycelium before introducing fresh air.

Fruiting Conditions

Once fully colonized:

• Increase humidity (90-95%) and provide indirect light.
• Introduce fresh air exchange (FAE) to encourage pin formation.
• Harvest once mushrooms reach maturity, typically within a week of fruiting.

Common Issues and Their Solutions

Problem: Slow Colonization

• May be due to low temperatures, improper moisture, or compacted substrate.
• Solution: Keep temperatures within the ideal range and ensure even distribution of spawn.

Problem: Mold or Bacterial Contamination

• Signs: Green mold, black spots, or foul smells.
• Solution: Ensure all materials are pasteurized and keep work areas sanitary. If contamination spreads, discard the batch.

Problem: Overly Wet or Dry Substrate

• A field capacity test helps prevent excessive drying or waterlogging.
• Adding extra vermiculite can correct overly wet substrates.

Which Mushrooms Grow Best in CVG Substrate?

Ideal for CVG:

✅ Psilocybe cubensis – Thrives in CVG and one of the most commonly cultivated species.
✅ Oyster Mushrooms – Can grow successfully, though straw-based mixes may be more optimal.
✅ Lion’s Mane – Can be grown in CVG but performs better in hardwood/coir mixtures.

Not Ideal for CVG:

❌ Shiitake & Reishi – Require hardwood-based substrates such as sawdust or wood chips.

Storing and Reusing CVG Substrate

• Store unused CVG in sealed containers in a cool, dry space.
• Used CVG substrate may support multiple flushes of mushrooms if free from contamination.
• Old or spent substrate can be composted to enrich soil.