Outdoor Cultivation

Outdoor mushroom cultivation is fun and easy!


Drill 4 to 5 rows of holes in an evenly spaced “diamond” pattern.


Insert the dowels into the holes and gently tap them in.


Seal the dowels with some wax.

Helsieni Shop

Download Instructions Here (PDF)

1. Selecting your wood

Cut your logs in late winter/early spring just before tree buds sprout. Your logs and stumps should be clean and have their bark intact. We recommend using logs with a diameter of 10 to 30 cm and around 1 m long. Let freshly cut logs rest for 1-2 weeks before inoculating them. You can inoculate logs up to 3 months after they have been cut.

2. Select your mushroom

Helsieni sells mushroom dowels inoculated with different types of mushroom species. The table below will help you select a suitable mushroom to grow on your logs.

NOTE: The table above is meant as a guide, and only partially based on results achieved in Finland. This table will be constantly updated as more people share their successes or failures of their cultivation projects with us.

Our selection







Helsieni Kauppa

3. Drill holes

Drill 35mm deep holes, just a few mm longer than a dowel. TIP: Use (duct) tape to mark your drill bit at the right length. Make 4 to 5 rows of holes, no more than 15 cm apart, and in an evenly spaced “diamond” pattern around the log. If inoculating stumps, the holes should be drilled along the circumference of the face of the stump, in the area between the bark and heartwood, around 10 cm apart.

4. Inoculation

With clean hands, take the dowels from the bag (you may have to break them apart from each other) and insert them into the holes. If they seem a little tight, use your mallet to gently pound the plug into the hole. The dowels should go all the way into the log. Repeat this for all the holes you have drilled and don’t leave any drilled holes empty. Seal the holes with a food grade wax. This will help retain moisture and prevent the invasion of parasites and competitive fungi. If you don’t have any wax, you can also wrap cling film around your log.

5. Incubation

Place the logs off the ground, on branches, pallets, etc. Do not put your logs in direct contact with soil. Put them in a moist, shady area under a forest canopy. It’s important that sufficient moisture is maintained to support the growth of the mushroom mycelium, so you might need to water them occasionally. You can help with moisture retention by covering your logs or stumps with a sheet of burlap or shade cloth. Let the logs incubate for 6–12 months. The mycelium will fully colonize the wood. White edges are a sign of good incubation. The length of time needed depends on the species of mushroom, wood type, and the size of the log. Smaller diameter logs will incubate more quickly than larger logs.

6. Fruiting

A log that is well colonized will give mushrooms under the right conditions albeit unpredictably. If you want to trigger the mushrooms to fruit earlier, you can force fruit the logs by soaking them in cold water for 12 to 24 hours. The mushrooms should come out within 7-10 days after soaking. After fruiting, logs need to be rested for 6 to 8 weeks before being forced again.

For Professionals

If you are interested in setting up a commercial scale operation (>100 logs), please get in touch! We can help you with training, equipment and selecting appropriate mushroom varieties. We are currently looking for farmers who want to work together and develop the outdoor mushroom cultivation industry in Finland. We highly recommend visiting the mushroom cultivation section of the Small Farms Program of Cornell University. They also produced an excellent best practices manual. Download the PDF: Best Management Practices for Log-Based Shiitake Cultivation.