Plug Spawn

Plug Spawn

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Grow mushrooms on logs and stumps

Mushroom plug spawn is the simple way to get mushrooms growing on logs or stumps

Plug spawn is used to inoculate logs or stumps which involves drilling holes into hardwood logs and stumps and filling them with plug spawn. Inoculation is just a fancy term for sticking your spawn into the substrate- similar to planting seeds. This is one of the easiest ways to grow mushrooms.

The basic idea is that the mushroom mycelium colonizes a log or stump, feeding on the organic matter; when fully colonized it will produce mushrooms that continue growing from the same logs providing you with a bountiful harvest of fresh mushrooms year after year.

Plug spawn is the perfect product for beginners who want to start growing mushrooms because it is cheap, easy to use, and does not require any specialized equipment. Backyard mushroom cultivation has never been easier.

Equipment you will need

Inoculating logs is easy. In addition to mushrooms plugs, and logs or stumps, you will also need a drill, a hammer, and some wax (soy wax, beesewax, cheese wax, and paraffin wax all work fine) to cover the plugs after inoculation. You can buy a drill bit specifically designed for drilling holes for mushroom plugs, but a 5/16" bit from any hardware store will work for mushroom plugs. You will also need a crockpot or camp stove to melt your wax and a paintbrush for wax application (a natural bristle or foam paint brush is fine).


Tree species selection is important.

Many species work well for mushroom production. We recommend using fresh-cut, disease-free hardwood logs. You should never cut logs from a dead or unhealthy tree- only use recently cut wood from healthy living trees. Oak and sweet gum both work great, especially for shiitake mushrooms which is our favorite mushroom to grow on logs (sugar maple, hickory, and fruit trees will also work). Pine/conifer is not ideal for mushroom production. The only mushroom species we sell that will grow on pine/conifer is Pleurotus pulmonarius, also known as the phoenix oyster.

Log Size

The ideal log size is 3-4 feet in length and no larger than 6 inches in diameter. You can inoculate a larger diameter log or large stump, but it will take longer to colonize and produce mushrooms.

Moisture content

Maintaining adequate moisture content in mushroom logs is very important. The total number of mushrooms you produce is dependent on moisture, and the easiest way to prevent production altogether is by allowing your logs to completely dry out.


Summer or fall inoculation is best. Spring inoculation is not ideal as trees are more prone to shedding bark when handled during the spring. Mushroom logs must maintain an intact bark layer.

To inoculate logs, drill holes in alternating rows down each log. The holes should be arranged such that there is 1 row for every inch of diameter of log thickness. For example, a 3-inch diameter log will have 3 rows of holes.

After the holes are drilled, tap in your plug spawn using a small hammer and cover the holes with melted wax using a paintbrush.

Log spacing

Logs should always be kept away from direct ground contact to avoid competing fungi growing from the soil into the logs. Freshly inoculated logs may be stacked tightly together while they are colonizing. After an initial incubation period of 6 months, logs should be spaced out underneath trees or shade cloth to allow room for mushrooms to form.


Mushrooms fruit seasonally from mushrooms logs. This usually happens in early spring, after the average last frost date and again in the fall. Logs will not produce during the winter in cold climates.


Which species should I grow?

Certain mushroom species perform better than others on logs. We recommend shiitake mushrooms as they are high yielding, reliable, and pest resistant. Shiitake are mushrooms you can expect to work well on logs. A couple of other species we recommend for beginners are oyster mushrooms and lion's mane. Other exotic gourmet mushrooms such as hen of the woods and chicken of the woods require

What's in the bag?

In addition to complete instructions, each kit contains approximately 100 hardwood dowels (sterilized birch plugs) colonized with pure mushroom mycelium. Each bag will inoculate just a few logs (3-5). We only use spiral grooved dowels to ensure rapid mycelial recovery and increase your chance for success!

What if I am planning to inoculate a bunch of logs?

If you are planning to inoculate many logs, sawdust spawn is a more cost-effective option but requires specialized tools for inoculation.

When will my mushrooms fruit?

Log cultivation requires some patience. Most mushroom logs usually take at least 6 months to a year to produce mushrooms. This is because the mycelium must fully colonize the wood before it will produce mushrooms.

Wholesale Customers

Mushroom plug spawn is also available to resellers and distributors. Please contact our sales team for more information.