Growing on logs

How many dowels do I need?

Here is the formula to estimate the quantity of dowels you need:

Length (meter) x diameter (cm) x 2.5 = number of dowels required.

Example:
A log 1.2m long, 16cm in diameter.
-> 1.2 x 16 x 2.5 = 48 dowels for the log.

When to cut wood?

Choose wood cut during the dormant period, i.e. autumn-winter, before the sap rises. There are two really optimal periods: in the fall when the leaves start to change color and at the end of winter, just before the sap rises in the trees and the buds bloom. This way, the bark will hold on to the trunk longer, and the results will generally be better.

That said, if you have wood at another time of year, it will end up being degraded by a fungus anyway (because fungi are the only organisms capable of decomposing lignin in wood), so you might as well seed it. with a mycelium that will produce mushrooms that you can eat.

We recommend using fresh wood, which has been cut within 2-3 months maximum before sowing. Inoculation is optimal within 2 to 3 weeks of cutting. Depending on the species, it is sometimes recommended to wait 2 weeks before inoculation: on the one hand because this gives time for certain antifungal compounds to degrade, and on the other hand because the wood cells will already be weakened, which will be more conducive to mycelium.

But the longer you wait, the greater the risk that other mushrooms will already be established and not leave room for the one you are going to inoculate in the log. It is also that wood tends to dry out, mainly in summer and winter depending on the region. If the wood seems too dry, you can soak it in water for 12 to 24 hours before sowing.

It is also recommended to use healthy wood, free of diseases and traces of other mycelia.

The first weeks following inoculation, it is recommended to protect your logs from severe frost: indoors, sheltered from a wall, cover with dead leaves or straw, blankets, tarpaulins, etc. Covering the logs will also limit drying by wind and sun by providing optimal mycelium for the proper development of the mycelium. The mycelium needs to breathe a little so do not enclose your logs in 100% waterproof tarpaulins.

Wood species

Hardwoods like oak, maple or beech will generally take longer to produce their first mushrooms, but they will also produce mushrooms longer.

Conversely, birches or poplars will quickly become colonized by mycelium and will yield more quickly. But in the end they will generally produce fewer years and therefore fewer mushrooms.

There are always exceptions: oyster mushrooms will generally perform better on birch or poplar than on oak, but they will also perform well on beech.

The list of species is of course not exhaustive and should not prevent you from making your own experiments. We will be happy to read your feedback if you wish to share it with us by email: contact@lamycosphere.com

The diameters

We recommend a diameter ranging from 10 to 25 cm. Larger diameters will take longer to colonize and will therefore take longer to produce, but they will also last for more years. They also resist drought better than small diameters. The wood is generally cut in sections of 1m length, which facilitates handling.

An exception in terms of diameters: shiitake. Shiitake mycelium mainly feeds on the sapwood of the wood, that is to say the layer of wood which is located towards the outside. We therefore recommend a smaller diameter for shiitake, ranging from 8 to 15 cm.

For diameters of 30cm and more, we recommend the totem pole technique: superimpose sections 20-30cm high, with a 1cm layer of mycelium on sawdust between each section. This technique is particularly suitable for oyster mushrooms, lion’s mane and reishi.

The stumps of recently cut trees can also be inoculated, and produce over a period of 5 to 10 years. All of the roots have a considerable quantity of wood which can nourish the mycelium over the long term. The crucial period is 4 to 8 weeks following inoculation because it is necessary to be able to maintain sufficient humidity so that the mycelium can establish itself in depth. Subsequently, the mycelium will have access to a large quantity of carbon in the soil, while being able to capture the humidity it needs from the soil.

Mycelium on dowels or sawdust?

For growing on logs on a small scale, mycelia on pegs are best suited. The only equipment needed is a drill, an 8 or 9 mm drill bit, a hammer and possibly a brush. It is therefore within everyone’s reach.

For larger scale production (100-200 logs), it becomes more interesting to work with mycelium on sawdust. The advantage of this type of mycelium is its lower cost, but also colonization of the logs a little faster than on dowels. This only becomes interesting with the acquisition of certain specific tools such as a manual/automatic inoculator and bits adaptable to grinders. We also offer mycelium on sawdust on order in bags of 3 or 5 kg, you can contact us by email for more information on this subject.

How long does mycelium last?

Mycelium on pegs or sawdust keeps very well in the fridge. We recommend using it within 6 months of receipt. The ideal is to use them more quickly of course, because the mycelium gradually loses strength, and the risk of contamination increases over time.

The traditional log technique

1. Use a wood drill bit of 8 or 9 mm for inoculation with dowels or 12 mm for inoculation with mycelium on sawdust. Make holes 3 to 4 cm deep all around the log. The holes should be a little deeper than the dowels. Make staggered holes every 5 to 10 cm.
2. Insert the dowels into the holes, using a hammer if necessary. The dowels must not protrude beyond the holes. For inoculation with mycelium on sawdust, a suitable tool is recommended.
3. Cover with wax. The wax serves to protect the mycelium from drying out, as well as insects and diseases. Otherwise, you can also use paraffin, cheese wax or even green clay. This is particularly important for mycelium on sawdust. For inoculation with dowels, it is possible to do without them provided that you take more precautions about drying out the logs after inoculation.
4. Wait. Depending on the varieties, wood species and diameters, you will have to wait between 6 to 18 months. Place your logs in a shaded area sheltered from the winds. Avoid direct contact with the ground which could bring small insects and contamination with soil fungi. For example, you can place them on a pallet, covered with a tarpaulin or sail. In case of heat, pour a sprinkling of water on the logs occasionally to prevent them from drying out. For this first incubation phase, the logs can be piled up. After 3 to 6 months, you can space them out. For oyster mushrooms, maitake and reishi, we recommend burying them a third of the way into the ground so that they can capture water from the soil. Oyster mushrooms usually appear in late fall and early spring.
5. Harvest and taste your produce. A log made in good conditions can produce mushrooms for 3 to 5 years.

The stump technique

Stumps take longer to colonize and produce than logs, but can produce mushrooms for almost 10 years. The stumps must have been cut recently. They must also be located in a shady and humid place to avoid drought. If possible cut the stump 20 to 40 cm above the ground to facilitate inoculation.

To avoid regrowth or shoots, you can “surround the trunk at the base” by removing a 3-4 cm strip of bark at the lowest ground level.

The strains can be sown with mycelium on pegs, or on sawdust (see images)

1. Use a wood drill bit of 8 or 9 mm for inoculation with dowels or 12 mm for inoculation with mycelium on sawdust. Make holes 3 to 4 cm deep all around the stump. The holes should be a little deeper than the dowels. Make staggered holes every 5 to 10 cm.
2. Insert the dowels into the holes, using a hammer if necessary. The dowels must not protrude beyond the holes.
3. Cover with wax. The wax serves to protect the mycelium from drying out, as well as insects and diseases. Otherwise, you can also use paraffin, cheese wax or even green clay. This is particularly important for mycelium on sawdust. For inoculation with dowels, it is possible to do without them provided that you take more precautions about drying out the logs after inoculation.

The totem technique

The totem technique is particularly suitable for sections with a large diameter (>20 cm). The antlers are cut into sections 20 to 30 cm long, layered in a sandwich with a layer of mycelium between each section. This technique is particularly suitable for oyster mushrooms, lion’s manes and reishis.

A 3 kg bag of mycelium on sawdust allows you to sow approximately 4 to 6 overlapping sections of wood measuring 30 cm in diameter.

1. Cut 3 sections 20 to 50 cm long. Also count a hat of approximately 5 cm which will come on top.
2. Place the whole thing in a shaded and humid place.
3. The base of the totem can be a stump. Otherwise start by placing a layer of brown cardboard on the ground. Put a first layer of 2 to 3 cm of mycelium on sawdust. Then build your totem with a layer of mycelium between each section, and finish with a 5 cm hat. A bag with holes can be used to completely cover the totem. This will allow optimal development of the mycelium, protected from drought. Failing that, you can also cover the edges with wax.
4. Be careful during the first 6 months that the mycelium does not dry out. You can remove the bag when you see mycelium clearly present on the logs.
5. Once your logs are well colonized (6 to 12 months), the totem can be left as is for fruiting. You can also divide it so that each section is in contact with the soil to limit drying out.

For certain varieties such as maitake, namekos or reishis, it is recommended to partially bury the logs in the ground after colonization. This will help maintain constant humidity, but also stimulate fruiting through contact with soil bacteria.

How do I see if my logs are well colonized?

You can look at one end of the wood. You should see mycelium (small white filaments). The mycelium does not always cover the entire wood and that is not serious. Initially there may be small surface molds which develop on the edges, they feed on the remaining saps which come out of the wood. If the end has dried out (which you should try to avoid), the mycelium may not be visible. You can then cut off a part to see the mycelium inside the wood.

Place your logs in a naturally humid place: undergrowth, bushes, etc. Initially avoid putting the log in contact with the ground to prevent other native mushrooms from competing with our mycelium. You can place your logs on a pallet if you have a lot, or simply on small pieces of wood that will raise your logs.

In drought conditions, occasional watering may be necessary. Conversely, be careful not to keep them soggy or humid for too long, the mycelia need to breathe.

On a professional scale, you can use a shade sail and sprinklers to maintain high humidity during mushroom growth.

To thoroughly moisten your logs, the ideal is to soak them for 12 to 24 hours in a basin of water.

After the incubation period (6 to 12 months) it is necessary to space the logs. This brings in more air and leaves room for the mushrooms to develop properly and also makes harvesting easier.

Mushrooms tend to grow naturally after cool, humid periods. This can be done by soaking the logs in a basin of cold water for 12 to 24 hours (avoid tap water which contains chlorine, or let the water sit for a few hours beforehand). This works particularly well for shiitake. Note that you must leave at least 1 month of rest between each harvest.

How long should you wait before harvesting mushrooms?

The period of wood colonization (incubation) varies depending on mushroom varieties, wood species and section diameters, and temperature. The duration can therefore vary between 6 months and 2 years.

The oyster mushroom is a faster and more aggressive variety than most other cultivated varieties. Thus, logs inoculated at the end of winter can already produce mushrooms in the first fall. For shiitake for example, it will take 18 months. So don't despair if you don't see your beautiful mushrooms arriving in the first year.

Most mushrooms need cool and humid conditions to grow. If these conditions are not met, they will not grow.

The quantity of mushrooms depends on many factors, so it is impossible to give a precise figure. Generally there is between 10 and 20% of the weight of the log in fresh mushrooms harvested over the entire cultivation cycle.

Other readings

To go further in the readings, you can download the following two pdfs:

Growing mushrooms on logs in the undergrowth (N.Sénéchal, 2008)

Cultivation of mushrooms on logs and stumps: Technical guide (CRE, 2008)

Happy growing!