Log Inoculation Instructions
(for dowel/plug spawn)
Growing mushrooms on logs is a way to ensure a supply of mushrooms for years to come. These instructions apply to all of our dowel/plug mushroom spawn which is designed for inoculating logs.
Each species of mushroom is a different growing experience. Even if you have grown mushrooms before, please read the instructions for your kit carefully before proceeding. If you run into any problems please see our FAQ.
Storage and Handling
When you receive your dowel spawn, keep them at room temperature (17-22 degrees celsius) for 2-3 days to allow the mycelium to recover from transportation. Keep dowels in their unopened bag until use.
If not using your plug spawn right away, it can be stored at room temperature in a dark cupboard for up to 1 month. Do not store next to heat sources.
For long term storage, the plugs can be stored in their unopened package in a fridge. They will be viable for up to 6 months from the date of receipt. Do not freeze!
Let plugs sit at room temperature for 24 hours before use.
Use all plugs in an opened bag within 2 weeks. You can reseal the bag and refrigerate leftover plugs in the fridge.
Items you’ll need for this project
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An electric drill and 8mm drill bit suitable for wood (available as an add on in our shop)
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A mallet
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A container such as a jar or bowl for melting the wax
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A brush or sponge applicator to apply the wax (available to buy here)
Log Selection
Most hardwood species are well-suited for mushroom cultivation, with oak, maple, poplar, beech, and alder being among the most reliable choices for consistent yields.
Hardwoods provide a better nutritional profile for fungi, as they contain higher levels of lignin compared to softwoods like pine and spruce. Additionally, softwoods have high concentrations of resins and essential oils, which can inhibit fungal growth. Phoenix oyster is an exception to the rule in that it does grow on conifers.
Logs for mushroom cultivation must be:
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Fresh - no more than 6 weeks since being cut. Any longer and competing fungi in the environment will have a chance to grow and colonise the wood, competing for resources and reducing your chances of success.
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From healthy, disease-free trees. If there are any signs of disease such as patches of discolouration (black, green, or white) in the cross section, soft areas, large splits in the wood, or bark that is loose and beginning to separate from the log, then it’s best not to use this timber.
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Undamaged - avoid logs that have large cracks and bark that is loose, as these are areas that are open to infection from other organisms and will also loose moisture more quickly
Size:
A good size range to stick to is 50cm-100cm length, and from 8cm - 25cm in diameter. Any larger and the logs will be difficult to handle. It’s important to consider how the logs will be moved and what size will work best for the space you have.
Inoculating Your Log
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First, ensure the surface of the log is dry. Use a drill depth gauge or a piece of tape on your drill bit at around 3.5cm-4cm (slightly longer than your dowels - make sure to measure from the flat end of the drillbit and not the point) to ensure even holes that are the correct depth every time. You will be drilling holes around the circumference of the log only and not the cut ends of the log.
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Start drilling 2 inches/5cm from the cut edge of your log. Drill a row of holes 15 cm apart along the length of your log. When drilling ensure that the drill but is at a right angle to the surface of the log so that you create a straight hole.
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Once your first row of holes is complete, you’ll want to position your next holes in a staggered row so that they create a diamond pattern. Leave around 6cm between the first row and the next. Keep repeating until the entire curved side of the log is covered in evenly spaced holes.
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Insert dowels immediately after drilling.Tap dowels in with a mallet so they sit just below the bark surface.
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It’s a good idea to label your log with the date and mushroom species - successfully inoculated logs can take 12-24 months to produce their first harvest!
Once all the holes have been filled with dowels, seal them with the wax provided (instructions are in next section).
Please note: plug spawn bags should not be left open for extended periods, as the mycelium will dry out. Ideally, all of the plugs from one bag should be used once the bag has been opened. If not using all of the plugs immediately, reseal the bag and store in the fridge. Plugs from a bag that has already been opened should be used within 2 weeks.
Diagram showing how holes should be spaced, with each row staggered.
Sealing the holes with wax
We recommend sealing the plug holes with the wax provided. Sealing the holes protects the mycelium from drying out or being eaten by critters as well as sealing it off from other microorganisms that can compete with the mycelium of your plug spawn. Each 40-dowel kit includes 25g of wax, enough for a log of 50cm length.
Melting the wax
To melt the wax, we recommend using the bain-marie method to prevent direct heat, which can cause overheating and scorching.
You'll need two containers: a large pan for water and a smaller one (such as an old jar) for the wax.
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Place the wax pellets in the smaller container and set it inside the pan. Fill the pan with hot (not boiling) water, ensuring the water level is above the wax but below the container’s rim to prevent overflow.
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Heat gently on low to medium, allowing the wax to melt slowly. Avoid letting water bubble over into the wax container.
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Bear in mind that wax can be difficult to clean from a container, so it can be a good idea to allocate an old pot or bowl to the job.
Sealing the holes with wax
Apply the molten wax over and around the plug with a small brush. To ensure it is properly sealed, you can apply a second coat once the first has set. Any visible bark damage and wounds where branches have been removed can also be sealed to help the log retain moisture.
Incubating your log
Once you have inoculated your log, you will need to keep it somewhere shaded from sunlight and sheltered from strong winds at all times so that it doesn’t dry out. It is vital that the log does not fully dry out as this will kill the mycelium.
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For the first 6–9 months, the mycelium is still establishing itself within the log. To reduce competition from soil-borne microorganisms, raise the log off the ground by placing it on top of bricks or wooden pallets.
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In warm and dry conditions, water logs for 5-10 minutes once or twice a week to maintain moisture. You can also help retain moisture by covering them with a breathable fabric such as burlap, horticultural fleece, or shade cloth. Avoid plastic, as it can encourage mould growth.
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During the first three months, protect the log from freezing temperatures by covering it appropriately.
Incubating several logs at once?
Multiple logs can be stacked in crisscrossed piles, called “crib stacks” to help conserve moisture and space.
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Pick a flat surface – find a level spot so the stack doesn’t tip over.
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Lay the first layer: depending on how many logs you need to incubate, put 2 to 4 logs side by side, leaving some space between them for airflow.
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Lay the second layer: place the same amount of logs on top, but turn them the opposite way so that they are laying perpendicular to the first layer.
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Keep stacking: repeat this pattern, alternating directions with each layer. Ensure the height of the stack is no more than 2-3 times the width.
When stacking logs, it’s good practice to keep those inoculated with the same mushroom species together and separate different species to prevent competition.
Checking progress
Between six and nine months after inoculation, you should start seeing patches of white mycelium at the ends of the log. This indicates that the mycelium from the initial plug spawn has successfully spread and begun colonising the log. However, if no mycelium is visible after 12 months, it may have been outcompeted by other wild fungi.
Note that during the winter months when temperatures are cold, growth will progress much more slowly.
Fruiting
When the mycelium has gained enough energy and conditions are favourable, your log will produce its first flush of mushrooms. This can take anywhere from 12-24 months, so patience is key. Fruiting is triggered by the changes in temperature and rainfall which usually occur at the changing of the seasons.
Once the log has fruited naturally at least once, you can stimulate additional flushes by soaking it in cold water for no more than 24 hours, called 'force fruiting'. However, allow at least one month of rest before attempting to force fruiting again otherwise it will likely not work.
During warm and dry weather, mushrooms can benefit from a mist with clean water several times a day to prevent them from dry out as they grow.
Your log should produce mushrooms for several years, with denser woods such as oak producing for the longest period of time. The logs should flush naturally at least around 1-2 times a year whilst the fungi slowly work on breaking down the wood.
Harvesting
Before picking your mushrooms, make sure that it is the correct species. Although rare, there is a slim chance that another species has managed to colonise the log and fruit.
If you are in any doubt, feel free to send us an email or WhatsApp message with some photos for confirmation.
When harvesting, we recommend thoroughly removing all parts of the cluster that is attached to the wood. This can be done by firmly grabbing and twisting at the base or by using a sharp knife to cut as close to the log as possible.
If not using right away, store freshly picked mushrooms in the fridge in a breathable container such as a paper bag. Plastic bags and airtight containers are not recommended as these trap moisture and will cause the mushrooms to spoil faster.
We hope you've enjoyed growing your Blue Oyster mushrooms!
We're passionate about sharing the diversity of the fungi kingdom & making more of its edible & medicinal delights easy to grow. Want to try another strain or learn how to cultivate mushrooms? See our full range of mushroom growing kits and cultivation workshops!