How to Make Your Own CVG Substrate for Mushroom Growing (CVG Recipe UK) No Ounces No Quarts

When it comes to growing mushrooms, the right substrate is crucial for success. One of the most popular substrates among mushroom cultivators is CVG (Coco Coir, Vermiculite, and Gypsum). This simple yet effective mushroom growing medium has been a staple for both beginner and advanced growers due to its excellent moisture retention, ease of use, and affordability. In this post, we will walk you through how to make your own CVG substrate, what it is, and why it’s considered one of the best mushroom substrates for bulk growing. This recipe is tried and tested many times over.

What is CVG Substrate and why is it the best for growing mushrooms?

CVG stands for Coco Coir, Vermiculite, and Gypsum, the three primary components used to make this mushroom growing medium in an ideal ratio. These ingredients work together to create a well-balanced, nutrient-rich environment for mycelium to thrive. Whether cultivating in a monotub or using sterile substrate bags, CVG offers the perfect balance of moisture retention, aeration, and nutrients, making it an ideal substrate for bulk mushroom cultivation.

• Coco Coir: This is a fibrous material derived from the husks of coconuts. It’s an excellent base for your substrate because of its ability to hold moisture while also providing a fluffy texture that allows mycelium to colonize easily.
• Vermiculite: This lightweight mineral enhances moisture retention and aeration, creating a perfect environment for the mycelium to grow. It also provides a slight buffering effect, which helps maintain the substrate's pH levels. We use medium grade vermiculite, for fine grade you may need a different amount of water.
• Gypsum: While not strictly necessary, gypsum is commonly added for its beneficial minerals, particularly calcium and sulphur. These nutrients can promote healthy growth and larger yields.

Together, these ingredients form a highly effective and versatile substrate for mushrooms, it helps maximise your yield and maintain a healthy environment for mycelium growth.

Why Make Your Own CVG Substrate?

Creating your own CVG substrate offers several advantages. First, it allows you to have control over the quality and proportions of the ingredients. Second, it can save money when compared to purchasing pre-made substrates. Additionally, making your substrate is a great way to learn more about the mushroom cultivation process and gain valuable experience.

However, it’s essential to understand that making a quality substrate requires attention to detail, especially when it comes to the pasteurisation process. Pasteurising is the method used to eliminate unwanted bacteria, fungi, and other contaminants in the substrate before inoculating it with grain spawn.

What Type of Mushrooms Can You Grow with CVG Substrate?

Here are some of the best mushrooms you can grow with CVG substrate:

1. Psilocybin Mushrooms (Magic Mushrooms)

CVG is especially favoured for growing psilocybin mushrooms, such as Psilocybe cubensis. These mushrooms thrive in the moist, nutrient-rich environment that CVG provides simulating their natural grassy environments. Whether you’re using a monotub setup or Fruit In The Bag kit, CVG can support the robust growth of these mushrooms.

2. Oyster Mushrooms

Oyster mushrooms (Pleurotus ostreatus) are another great candidate for growing on CVG. They grow rapidly and flourish in Wood based substrates however will grow on CVG.

3. Lion’s Mane Mushrooms

Lion’s mane (Hericium erinaceus) mushrooms also grow on CVG substrate. These mushrooms benefit from the addition of wood-based substrates. The balanced structure and nutrients in CVG can promote strong mycelial growth and healthy fruiting.

4. Shiitake Mushrooms

Although shiitake mushrooms (Lentinula edodes) are typically grown on logs or sawdust, they can also be cultivated on a CVG mushroom substrate. The substrate provides a stable environment for mycelium to colonize, though it may require more attention to ensure optimal results.

What is Pasteurising and Why is It Important?

Pasteurising refers to the process of heating the substrate to a specific temperature for some time to kill off harmful organisms that could compete with your mushroom mycelium. The goal is to sanitise the substrate enough to allow for your fungi to grow without contamination.

To pasteurise the CVG substrate, you typically heat it to around 71°C for about 4 hours. This can be done by using a large pot or an oven, and it’s crucial to monitor the temperature to avoid overheating, which could degrade the quality of the substrate.

The Components of a CVG Mushroom Substrate

Here’s a breakdown of how to mix and prepare your own mushroom substrate:

Ingredients:

• 1kg Coco Coir: This provides a great base for your substrate, offering moisture retention and structure.
• 4L Vermiculite: Adds aeration and moisture retention to the mix.
• 40g Gypsum: Helps with pH buffering and provides essential minerals for the growth of your mushrooms.

If you want this CVG dry mixture, find it here. 

Preparation:

1. Mix the Coir, Vermiculite, and Gypsum: Coir typically comes in compressed bricks, break it up in small pieces. This part can be labour intensive. Mix all parts in a 20l bucket. Try and ensure an even mix.
2. Pasteurise the Substrate: As mentioned, pasteurising the substrate is critical to avoid contamination. You can pasteurise your CVG substrate by pouring in 4.5l of boiling water. Then place on a secure fitting lid.
3. Cool and Package: Wrap your bucket with a thick blanket to keep your substrate hot. After cooling for 8+ hours, the substrate is ready for inoculation with grain spawn. It is best to use your substrate immediately however if you purchase sterile bags, it can be stored.

Sterile vs Pasteurised Substrate

In mushroom cultivation, Pasteurisation and sterilisation are two methods used to prepare the substrate, but they serve different purposes.

• Pasteurisation works on the idea of killing harmful bacteria and moulds while leaving beneficial microbes alive. The risk with this method is most spores will survive these conditions and can cause contamination in your grows.
• Sterilisation involves heating the substrate to 121°C for a longer period, using a pressure cooker or autoclave. This method kills all microorganisms, both harmful and beneficial, ensuring the substrate is completely sterile. Sterile substrates are necessary for starting from grain spawn or for highly controlled setups, as they create a clean slate for the mycelium to colonize without interference from other organisms.

While making your own CVG substrate is a rewarding and cost-effective option, many growers choose to buy pre-made substrates for a few key reasons:

• Time-Saving: Preparing and Pasteurising the substrate will take hours, while buying pre-made substrate means it’s ready to go right out of the bag.
• Consistency: When purchasing substrate from trusted suppliers, you can expect consistent quality with every batch, which can be difficult to achieve when mixing your own.
• Less Risk of Contamination: The pasteurisation process requires careful attention to detail, and buying pre-made substrate reduces the risk of contamination that could compromise your mushroom crop.
• Correct moisture content: Knowing how wet mushroom substrate should be takes a lot of trial and error. That can mean a lot of failed grows. When you buy substrate made by professionals it negates these risks.

You can find sterile CVG substrate here.

Conclusion

Making your own CVG substrate for mushroom growing is a straightforward and rewarding process that can save you money and help you gain a deeper understanding of the cultivation process. With its optimal moisture retention, aeration, and nutrient profile, CVG is an ideal substrate for bulk growing your grain spawn. However, while it’s possible to make your own substrate, many growers prefer the convenience, consistency, and reduced contamination risk of buying pre-made sterile mushroom substrate. Whether you choose to DIY or buy, CVG remains one of the best mushroom growing mediums out there.