Plug Spawn: Grow Mushrooms on Logs & Stumps

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Mushroom Plug Spawn

Fungi Perfecti offers plug spawn of a number of hardy mushroom species: Reishi, Maitake, Lion's Mane, Shiitake, Pearl, Blue and Phoenix Oyster and Turkey Tail. These sterilized birch plugs are spirally grooved and fully colonized by pure mushroom mycelium, and are available in packages of approximately 100 and approximately 1000 dowels. Our Plug Spawn comes complete with our user-friendly, fully illustrated 14-page instruction booklet.

Shiitake mushrooms growing on oak logs
Shiitake mushrooms growing on oak logs

By using the dowels to inoculate cut hardwood logs or stumps, mushroom mycelium can be encouraged to grow throughout or colonize the wood. Once the wood is fully colonized (typically 9-12 months) mushrooms will spring forth from cracks or channels in the wood. Generally, the best time of year to inoculate logs and stumps is in the Spring, after your last hard frost. However, you can inoculate your logs any time up to 30-45 days before consistently (i.e. 'round the clock) freezing temperatures set in for the Winter. The idea is to allow the mushroom mycelium growing on the Plug Spawn time to establish itself in its new home before it goes into dormancy over the Winter. Logs can be left outdoors over the Winter, under a layer of straw or a burlap tarp, shade cloth or other vapor-permeable cover (do not use plastic tarps: this can cause mold to form). In areas where the Winter is exceptionally harsh, logs can be stored in a shed, barn, garage or other outbuilding.

Log end with mycelium
Characteristic "mottling" of mycelium on the end of a log that is ready to produce mushrooms

Our Plug Spawn grows on recently cut or fallen logs. Milled lumber, rotted wood or trees that have been down for longer than 6 months are not suitable. Logs should be cut to lengths of 3–4 feet, and are best if they do not exceed approximately 8 inches in diameter. Stumps of 6–14 inches in diameter are recommended for stump cultivation. Use a 5/16" drill bit to drill 1¼"-deep holes, evenly spaced around and along the logs. Stumps should be inoculated along the circumference of their face, in the border between the bark and the heartwood. Insert 1 plug per hole and whack it in with a rubber mallet or a hammer. A 3–4 foot log can take 50 or more plugs, while stumps usually hold 30–50 plugs. Holes can be sealed with cheese wax or beeswax to protect the mycelium while it is growing; although this step is helpful, it is not absolutely necessary. (Fungi Perfecti sells sealing wax for this purpose.)

We guarantee our Mushroom Plug Spawn to be viable. (In fact, if left unattended on a shelf or in your refrigerator for too long, many of our Plug Spawn species will begin to produce mushrooms right out of the bag!) However, the total number of mushrooms you can expect to get via log and stump cultivation will vary from log to log, and from season to season.

Any outdoor mushroom cultivation project involves a number of variables; climate, species, sugar and moisture content of wood, consumption of mushrooms or mushroom mycelium by insects and other animals, quality of care and just plain old chance, to name a few. Due to the many and various contributing factors involved in this method of mushroom cultivation, Fungi Perfecti cannot accurately predict the amount of mushrooms your Plug Spawn will produce.

Cross-Reference Chart: Wood Type to Mushroom Species

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