Organic Coco Coir Mushroom Substrate

Coco Coir Substrate – The Standard Bulk Substrate for Cubensis Monotub Grows

Our Coco Coir Substrate brick is the go-to bulk substrate for cubensis cultivation. Just add boiling water, let it hydrate and cool, mix with your colonized grain spawn, and layer into your monotub. No pressure cooker, no sterilization, no complicated prep.

How to Use Coco Coir Substrate in a Monotub

Once your grain spawn jars are fully colonized, hydrate the coco coir brick and mix it with your spawn at a ratio of roughly 1 part spawn to 3 parts substrate. Pack evenly into your monotub, seal it up, and let the mycelium finish colonizing the bulk layer before switching to fruiting conditions.

The low nutrient content of coco coir keeps contamination rates low while still giving your mycelium a moisture-rich environment to colonize and fruit from.

Why Growers Use Coco Coir for Monotubs

Coco coir is one of the most popular bulk substrates for cubensis monotub grows because it is forgiving, consistent, and easy to prepare. It holds moisture well without becoming waterlogged, has a naturally neutral pH, and does not need to be sterilized. For beginners, this removes one of the most common failure points in the grow process.

How to Prepare Your Coco Coir Substrate Brick

What you need:

• 1 Coco Coir Substrate brick
• Boiling water
• Large bowl or bucket

Step 1 - Hydrate the brick Place the brick in a large bowl. Pour boiling water over it and break it apart as it softens. Use roughly 3 to 4 liters of boiling water per brick.

Step 2 - Cover and pasteurize Stir well until fully broken up. Cover the bowl with a lid or foil and let it sit for 1 hour. The heat passively pasteurizes the substrate.

Step 3 - Check field capacity Let it cool to room temperature. Squeeze a handful firmly. You want just a few drops to come out. If it drips heavily, let it dry a little longer before using.

Step 4 - Mix with colonized grain spawn Once cooled, mix with your colonized grain spawn and layer into your monotub.

CVG-Calulator: Check out our cvg-calculator for the perfect substrate mix.

Substrate Specifications

Frequently Asked Questions

Do I need to sterilize coco coir? No. Hydrating with boiling water and letting it sit covered for an hour is sufficient preparation. No pressure cooker needed.

Can I mix coco coir with vermiculite? Yes. Many growers use a 50/50 coco coir and vermiculite mix. The vermiculite improves water retention and air exchange in the substrate. Our brick works well with this method.

How much does one brick make? One brick expands significantly once hydrated and typically fills a standard monotub when mixed with grain spawn.

Can I reuse the substrate after a harvest? Some growers reuse their substrate for a second or third flush by rehydrating and maintaining humidity. Results vary depending on contamination levels after the first harvest.