Growing mushrooms on freshly cut logs is using plug spawn is a popular and effective method. In this guide, we will provide step-by-step instructions on how to inoculate hardwood logs using plug spawn.
Mushroom plug spawn is used to inoculate freshly cut solid hardwood logs or stumps with mushroom mycelium, in order to grow mushrooms directly from the log or stump. While plug spawn is active fungi culture and can be transferred to any medium, it is typically used exclusively for this purpose. This methodology has the best long term return on investment, producing mushrooms for 5+ years. However, you will have to wait around a year to see your first mushrooms, because it takes time for that mycelium to work itself through the dense wood initially.
The Pros
- Best return for time invested.
- Does not require a flow hood or sterile equipment.
- Can be done with basic drill and hammer.
- Low tech outdoor growing.
- Produces mushrooms for many seasons.
- Easy to maintain after setup.
- One of the oldest known cultivation methods.
The Cons
- More up-front work preparing logs.
- You must have freshly cut hardwood available.
- Inoculation and harvesting must be timed with the seasons.
- You must wait about year before getting your first mushrooms.
Selecting Your Mushroom Species
This methodology can only be used for hardwood loving mushroom species like Oyster Mushrooms or Lion's Mane. These species require a hardwood substrate to grow. This methodology will not work for compost/bovine loving mushroom species such as Portobello.
Materials Needed:
- Freshly cut Hardwood logs
- Plug Spawn
- Drill
- 5/16" Drill bit
- Bees wax or cheese wax
- Brush or spoon for wax
Step 1: Selecting the Hardwood Logs
You will specifically need hardwood such as Alder, Ash, Birch, Bitternut, Cherry, Chestnut, Hophornbeam, Ironwood, Maple, Oak, Pecan, Sweet gum, Sycamore, Tulip poplar, Walnut, Willow, and even fruit trees. Oaks and hard maples are the preferred wood-types for most mushroom species because they're very dense and offer plenty of nutrition for a longer, sustained fruiting period. Poplars and other soft hardwoods will colonize faster and produce mushrooms sooner but generally don't yield as much or produce for as many years. Most target mushrooms do not grow on pine/conifers. The hardwood logs need to be freshly cut, within the past 20 days. Logs should be 4-10 inches in diameter, and cut to consistent length so they can be organized in stacks. We suggest cutting them 2-4 feet long. If you intend to inoculate a stump, it must be fresh cut as well. This is a good way to naturally break down stumps over a few years and turn them into something useful. Make sure the logs are free from any signs of disease, decay, or other contamination. Do not use stripped logs or logs with serious bark defects.
Step 2: Drilling Holes
Using a drill and a 5/16 inch drill bit, drill 1" deep holes into the hardwood logs. You can paint or wrap a piece of tape around the drill bit at 1" high to mark the depth you should go. Space the holes approximately 4 to 6 inches apart in a diamond or triangular pattern.
Step 3: Inserting the Plug Spawn
Take the plug spawn and insert one plug into each hole. Gently tap the plugs into the holes using a hammer or mallet until they are flush with the surface of the log.
Step 4: Sealing the Holes
Sealing the holes is optional, but recommended. It helps seal in the spawn and protect it from drying out or being exposed to contaminants. Melt wax, such as cheese wax or bees wax, in a double boiler or a heat-resistant container placed in a pot of boiling water. Pour or dab a small amount of melted wax over the plugs to seal them.
Step 5: Caring for the Inoculated Logs
Place the inoculated logs in a shaded area where they will receive no direct sunlight. Keep the logs moist by watering them regularly, especially during dry periods.
Step 7: The Long Wait
It may take several months to a year before the mycelium colonize the logs and begin fruiting. Most people inoculate logs in Spring to have them ready for the following Spring. This allows the logs the benefit of a cold shock through the winter. Mycelium is safe deep inside a 6" log during these times, even through freezing temperatures.
Step 6: Harvesting Mushrooms
Once the mycelium has fully colonized the logs and the environment is right, mushrooms will begin to appear. Harvest the mushrooms when they are at their desired size and maturity. Using hardwood logs with plug spawn can produce mushrooms for up to three years.
That's it! By following these instructions, you can successfully inoculate logs using plug spawn and enjoy a bountiful harvest of mushrooms. Happy growing!