How to Build an Easy Mushroom Fruiting Chamber

Building a fruiting chamber for mushrooms is a relatively simple process that can be done with a few basic materials. There are many different methods, however, I have found that this unmodified fruiting chamber is the cleanest and easiest fruiting chamber to make. Here’s a step-by-step guide to building an easy fruiting chamber for mushrooms:

• Plastic storage bin with lid
• Perlite
• Hygrometer
• Fan (optional)
• Outlet timer (optional)

Instructions:

1. Choose a plastic storage bin with a lid that is large enough to accommodate your growing substrate and mushrooms. Make sure the bin has an airtight seal when the lid is closed. We recommend a 27 or 30-qt bin for most applications.
2. Fill the bottom of the bin with a layer of perlite. Perlite is a naturally occurring volcanic glass that is often used in horticulture to improve soil drainage and aeration. Make sure your perlite does not have any additives. Find perlite at your local hardware store or buy it here.
3. Add water to the perlite until it is evenly moist but not waterlogged. The perlite should be damp, but not so wet that water collects at the bottom of the bin. Drain out any excess water.
4. Place a hygrometer in the fruiting chamber to monitor the humidity levels. Humidity is important for mushroom growth, and the ideal humidity range for most species is between 70-90% during fruiting.
5. Place your colonized substrate on top of the perlite layer. Make sure the substrate is spaced evenly and not touching the sides of the bin.
6. Close the lid and latch one side of the bin, leaving the other slightly ajar. This will help to create an environment with high humidity while allowing for a little bit of fresh air in.
7. If desired, you can add a small fan set on a timer to circulate air. This helps to promote pinning and remove stagnant air. In order to maintain a perfect balance of humidity and fresh air, make sure to use a timer that can operate at small time intervals, such as turning on for 5-10 minutes at a time. I will set this to turn on for 10 minutes 3 times per day. Also, make sure the fan is set to a low speed and is not directly blowing on the mushrooms. If you are not using a fan then you will want to remove the lid and use it to fan the cake 3 times per day.
8. Place the fruiting chamber in a dry area with ambient light and good ventilation. Ideally, the temperature should be between 65-75°F (18-24°C).
9. Check the humidity levels and moisture levels regularly, and add water to the perlite as needed to maintain the desired humidity range.

With these simple steps, you can create a basic fruiting chamber for growing mushrooms. Depending on the species of mushroom you are growing, you may need to make adjustments to the temperature, humidity, and other environmental factors, but these basic guidelines should work for many common species of edible and medicinal mushrooms.