Mushroom fruiting block kits offer an easy way to grow your favorite culinary and medicinal mushrooms indoors year-round at home. They save you time and effort and are perfect for beginners, kids, and anyone with limited space. You can keep them on a kitchen counter, in a grow tent, or other grow chamber. Here we cover how to use your mushroom fruiting block kit from start to finish, including what you can do when your block is used up.
What is a mushroom fruiting block kit?
A mushroom fruiting block kit is a block of sawdust inoculated with mushroom mycelium - meaning it’s ready to produce mushrooms with just a few steps.
What is a mushroom fruiting block kit made of?
Many culinary and medicinal mushrooms grow on hardwood trees, so fruiting blocks are usually comprised of hardwood sawdust with additional supplementation for nutrition and moisture-retention. Some of these supplements include wheat bran or soy hull pellets, coco coir, vermiculite, and gypsum.
Top-fruiting pioppino mushrooms.
What are the benefits of using a mushroom fruiting block kit?
1. Grow food. Grow your own food indoors, year-round, regardless of climate.
2. Save time. Your mushrooms can grow within 2 weeks depending on species.
3. It's easy. No extra equipment or experience is necessary for most species.
4. They're small. These 5lb blocks can fit in limited spaces.
How to fruit your mushroom fruiting block kit
Selecting the right fruiting method (the way in which your mushrooms will grow) is crucial to ensure healthy growth and optimal yields. Different mushroom species have specific preferences for how they fruit, which affects the way you should prepare your block. Below, we outline the two primary methods—side-fruiting and top-fruiting—so you can choose the best approach for your mushrooms.
1. Side-fruiting is ideal for mushrooms that form dense clusters and prefer smaller openings, such as oyster mushrooms (including blue, pink, golden, and Italian), lion’s mane, and chestnut mushrooms. Despite the name, side-fruiting doesn't refer to the direction of growth but to the cuts made on the sides of the bag where mushrooms emerge.
Side-fruiting golden oyster mushrooms.
2. Top-fruiting is best suited for species that thrive in humid, CO2-rich environments with a broad surface area for growth. This includes king trumpet, black king, nameko, pioppino, and reishi mushrooms. In top-fruiting, mushrooms grow from the substrate’s surface at the top of the block.
Top-fruiting black king mushrooms.
Shiitake blocks require specific handling. We’ll delve into these unique steps later.
How to store & prepare your fruiting block kit
If you need to store your blocks, most can be kept in the refrigerator for up to six months. However, pink oyster blocks should always be stored at room temperature.
To prepare your kit
• Use a sharp, clean cutting tool and a stable surface.
• Keep tape and rubber bands handy if needed.
• Set up your fruiting space, such as a Boomr Bin monotub or BoomRoom II grow tent, before opening your block.
How to side-fruit your fruiting block kit
1. Prepare the Block: Unfasten the taped top of the bag. Fold the top flap tightly over the block, keeping the filter patch facing up. Press out any excess air to minimize side-pinning. You can place rubber bands around your block to help with this.
2. Secure the Flap: Either tape it down or flip the block so the flap stays in place.
3. Orient the Block: Choose a position that fits your growing space, usually with the cut side facing up for stability.
4. Cut the Bag: Make an ‘X’ cut on the bag, starting an inch or two from the corner. Slice diagonally across the plastic. Cutting into the block is fine.
5. Set Up for Fruiting: Place the block in a suitable environment and mist it 2-4 times daily, adjusting for humidity levels.
You can option to place rubber bands on your block to prevent side-pinning.
Cut an 'X' in the bag.
A side-fruiting pink oyster block.
How to top-fruit your fruiting block kit
1. Prevent Side-Pinning: Wrap a rubber band around the top of the substrate.
2. Initiate Fruiting: Cut a small slit below the bag’s seam to increase oxygen.
3. Wait for Pins: Let the block sit until pins are about 1” high. This stage typically occurs within a couple of weeks, though it varies by species.
4. Trim the Bag: Once pins develop, cut off the top of the bag, leaving a 4” collar.
For reishi mushrooms, delay cutting the bag until the antlers are a few inches tall, which can take several months. Reishi cangrow effectively without opening the bag, but the restricted air will make the reishi form antlers that never fan out.
Place a rubber band around your block.
Cut a small slit below the seam to initiate fruiting.
Once pins are about 1" high, cut off the top of the bag.
Challenges with top-fruiting
Due to the exposed surface area, keeping your block from drying out is important. From when you cut the first slit in the bag, regular misting and/or keeping your block in a grow chamber is recommended. Multiple flushes can be harder to achieve with top-fruiting because of moisture loss. Experimenting with different sidewall or collar heights can affect growth, providing interesting results.
Special steps for shiitake
1. Identify Readiness: Shiitake blocks form a thick white wrinkled layer called 'popcorning' as they colonize. If you order a block from us, it may arrive this way. After a few weeks, the block should turn mostly brown, indicating that it is ready for fruiting. If pins are visible, you can begin fruiting regardless of block color.
2. Cold Shock: Place the block in the refrigerator for 24-48 hours.
3. Physical Stimulation: Give the block a firm slap to encourage growth.
4. Remove the Bag: Eliminate the bag completely or leave a bit on the underside to reduce bottom fruiting.
5. Soak the Block: For extra hydration, submerge the block in cold water for 4-12 hours.
6. Maintain High Humidity: Ensure humidity around 90% until pins form, preferably in a grow chamber for moisture retention.
'Popcorning' vs. early pinning.
A shiitake block ready to be cold-shocked.
Soak your shiitake block in cold water for 4-12 hours.
Where should I keep my fruiting block kit?
Choose a humid, temperate area with regular airflow and indirect light, like a kitchen counter. Basements or bathrooms can also be suitable. Using a growing chamber like a BoomRoom II grow tent or a Boomr Bin monotub can help you control humidity and air-exchange with a humidifier and fan - two key componants in growing mushrooms.
For frequent growers, a BlocksBox subscription regularly delivers fruiting block kits for continuous growing!
What should I do with my fruiting block kit when it's done?
Once your mushroom fruiting block has finished growing mushrooms, it can be used in a variety of ways. You can bury it in your garden to stimulate additional mushroom growth, add it to your compost bin for a fungal boost (fruiting blocks make great worm food!), use it as mulch in garden paths or around trees, or break it up and mix it into your garden/potting soil to help boost moisture retention, slow erosion and runoff, and absorb excess water. Simply speaking, returning your mushroom fruiting block to the earth helps boost soil nutrition and your plants will thank you for it!
Final thoughts on mushroom fruiting blocks
Growing mushrooms from a fruiting block kit offers a simple and efficient way to cultivate various gourmet and medicinal mushrooms at home or commercially. These kits come ready for fruiting, making them ideal for beginners or those with limited space. By following the proper fruiting techniques—whether side-or top-fruiting—you can optimize the growth environment for different mushroom species. The process involves minimal preparation, with most of the work already done for you, allowing for a quicker harvest. With careful attention to environmental factors like humidity and temperature, you can enjoy multiple flushes from your fruiting block, making it a cost-effective and rewarding way to grow your favorite mushrooms at home!