CVG stands for Coir, Vermiculite, and Gypsum—a widely used bulk substrate blend in mushroom cultivation. It is designed to provide the ideal balance of moisture retention, aeration, and nutrients to support healthy mycelial colonization and fruiting.

Our CVG Blend includes coco coir, which offers excellent moisture retention and structure, acting as the primary substrate component.

It contains vermiculite, which improves aeration and maintains consistent hydration.

Gypsum, another key nutrient, is included to supply calcium and sulfur to promote vigorous growth.

Additionally, we enhance the formula with worm castings to provide natural nutrients that support strong fruiting performance.

Redwood Mushroom Supply’s CVG Blend is pre-sterilized and packaged in sealed grow bags with a 0.2-micron filter patch for gas exchange. It is ready to use as a bulk substrate for growing dung-loving mushrooms in monotubs, shoeboxes, or grow bags. Once mixed with fully colonized grain spawn, it supports fast colonization, reliable pinning, and multiple productive flushes without the need for additional preparation or pasteurization.

CVG is ideal for growing dung-loving mushrooms, which naturally fruit on manure-rich environments. This includes many species commonly grown in monotubs, shoeboxes, and trays.

Note: This mix is not recommended for wood-loving mushrooms like shiitake, lion’s mane, or reishi. For those, use our Fast Fruiting MIx or Hardwood Mix instead.

Not ours! Our CVG is pre-sterilized and sealed—it’s ready to use as soon as it arrives. The substrate is pressure-sterilized in-house and packaged in grow bags with a filter patch for optimal gas exchange.

That said, clean technique is essential. As with any sterile substrate, it can still become contaminated during inoculation if care isn’t taken.

There are two methods to grow with your CVG—for both, you’ll need fully colonized grain spawn to inoculate this substrate—not spores or liquid culture.

🛑 Do not attempt to inoculate CVG directly with spores or liquid culture. Always use fully colonized grain spawn for reliable results.

The first is the Monotub Method:

You will need:

• 2 Bags of CVG
• 1 Bag of Colonized Grain Spawn
• 1 Monotub with Filters and Liner
• Gloves
• 70% Isopropyl Alcohol Spray
• Still Air Box (Recommended)

Monotub Method Steps:

• Clean and Sanitize your monotub, liners, grain & substrate bags, and area with 70% Isopropyl Alcohol. Ideally, do this inside of a Still Air Box.
• Allow your tub and supplies to dry - and do not use open flame inside your still air box.
• Place your liner into the bottom of the monotub.
• Open one bag of substrate and pour it into your liner.
• Break up your grain spawn, open and pour it onto the substrate.
• Open your second bag of substrate and pour it on top of the grain.
• Mix thoroughly and create an even flat surface.
• Place the top with filter covers onto the bottom bin and move to incubation area.

Growing in the bag is easy, requires less steps than the Monotub Method, and is a great way to familiarize yourself with mushroom cultivation.

Here is what you'll need:

• 1 Bag of CVG
• 1 Bag of Colonized Grain Spawn
• Gloves
• 70% Isopropyl Alcohol Spray
• Sealer, Clip, or Tape to seal bag
• Still Air Box (Recommended)

Bag Growing Steps:

• Put on gloves, spray grain and substrate bags, and place inside still air box.
• Break up your grain spawn inside the bag and open the bag.
• Open your substrate bag
• Pour 1/2 of the grain into the substrate. You can use the other half to inoculate a second bag if you have one.
• Seal the bag containing substrate and colonized grain using a Sealer, Tape, or a clip.
• Mix the grain and substrate thoroughly inside the bag by squeezing and pressing the bag from the outside.
• Once mixed, reshape the substrate into a brick gently and move to an incubation area.

Colonization typically takes 10–16 days, depending on temperature, spawn rate, and the health of your grain spawn. Ideal incubation temperature is 70–78°F. You’ll know it’s ready when the bag is completely white with mycelium and feels firm.

Your bag is ready to fruit when all conditions are met:

• The substrate is completely white
  
• It feels firm and solid
  
• You may see pins or primordia forming
  
• There are no signs of mold or contamination
  
  

To Initiate Fruiting:

1. Cut a 1-2" slit beneath the filter patch when you see small mushrooms forming.
2. Thats it. Seriously.
3. Seriously, why are you still reading?

Fruiting in the bag is a simple process - the bag will maintain the ideal humidity and airflow needed to support your mushrooms as they grow. The more you mess with it, the more likely you are to introduce contamination to future flushes.

To Initiate Fruiting in Tubs:

1. Remove any excess tape from bottom holes of tubs
2. (Optional) Remove lid and add a layer of CVG Mix to the top of your monotub to retain surface moisture.
3. Replace lid and place in a room with indirect light during the day or on a 12 on/12 off light cycle.
4. If needed, gently mist tub surface. Do not mist more than once per day.

It's generally recommended to maintain room temperature when growing with CVG during fruiting. Your Monotub or Grow Bag should maintain the ideal conditions for growth.

Typically you can expect 2-3 flushes per mushroom block.

• First flush is the most productive
  
• Second and third flushes are smaller
  
• Total yield varies by species and environment
  

For Second and Third Flushes:

• Let the block rest for 4–5 days
  
• Spray inside of bag or surface of tub
• Close bag or tub and monitor for growth

Not for indoor cultivation—but it’s still useful!

• Add to compost piles or garden beds
  
• Use as mulch or soil amendment
  
• Inoculate outdoor mushroom beds
  
  

Troubleshooting slow colonization:

Contamination – green, black, or pink spots; foul smell

Temps too low/high – below 65°F or above 80°F can slow or stall growth

Overhydration – water pooling in the bag

Old or weak spawn – expired or improperly stored grain spawn may not perform

If unsure, contact Redwood Mushroom Supply with photos for assistance.