Growing with Plug Spawn - Grow Mushrooms Canada (2024)

Growing outdoors on logs takes patience, as it can take anywhere from 6 months to several years before enjoying your first crop of mushrooms, depending on type of mushrooms, type of wood, diameter of log, and the length of your growing season.

Oyster mushrooms tend to produce very quickly (ours produced mushrooms the first fall after early spring planting). By contrast, our shiitake took 1.5-2 years before the first mushrooms popped out, and we are growing on Vancouver Island BC where the winters are mild and short. In colder areas of Canada with a shorter growing season spring to fall, the time to first crop might be further delayed.

The diameter of the log also matters, with smaller logs producing more quickly (but for not as many years) as larger logs. When we inoculated a very large alder log with shiitake, it was at least 3 years before we saw our first crop. But one rainy fall, we got our first shiitake and they were the size of dinner plates! No joke!

Typically, the denser the wood (like oak), the longer the wait for your first crop of mushrooms. But once your log is ready to fruit, you will enjoy seasonal crops for ~5-7 years. Fast-growing trees like poplar will produce mushrooms quickly (as soon as 6 months) but have a shorter production life (~3 years).

If you want faster rewards, consider growing a which will generally produce mushrooms within weeks, and a couple more crops over a period of months.

Plug spawn is very easy to use and requires tools that are found in most households. You will need a proper size drill bit to drill holes, a hammer to tap the plugs into the holes, and a paintbrush or wax dauber to apply melted wax to cover them. To easily drill holes to the proper depth each time, fit a depth stop on your 8 mm (5/16″) drill bit or purchase a special high speed 8.5 mm drill bit with built-in depth stop.

Sawdust spawn requires the purchase some special tools, but is a more economical option if you have lots of log to inoculate year after year. Drill 12 mm holes in your logs. For fastest drilling, use this 12 mm drill bit with built-in depth stop with an adapter to convert your angle grinder to a high speed drill. Fill the inoculation tool with sawdust spawn, and “punch” the pellet into the hole. Cover with melted wax using a wool dauber.

While we recommend using your mushroom plug spawn as soon as possible while they are at their prime, they can easily survive for months refrigerated in a cold dark place. (In fact fungal mycelium is amazingly resilient, and cultures are often still viable even after a year or more!)

A small amount of yellow or amber liquid may collect in the bottom of your bag over time. Not to worry, the liquid is naturally-forming metabolites, a by-product of mycelium growth. It is still perfectly good to use.

“Wide”, “warm”, or “cold” indicates the conditions under which this strain of shiitake will generally produce most prolifically. All three kinds of Shiitake can be grown across Canada! Even if your region has cold winters, you can still grow the warm strain in the summer. When choosing which variety to grow, we recommend that you consider your local climate, and your Shiitake production goals.

For instance, here on Vancouver Island, BC the summers are very dry, whereas the spring and fall tend to be rainy and humid. We decided to work with nature, and select strains that tend to fruit in the spring and fall when it is humid here, rather than fight to keep the logs watered during the summer drought. The wide temperature strain is a good all-around choice, and the cold strain helps us to extend our fruiting season as early as possible in the spring and later into the fall.

If your goal is to have mushrooms spring, summer and fall, then a combination of wide and warm strains would be a good choice. In some parts of Canada summer heat is often accompanied by high humidity, and this would be suitable for the warm strain Shiitake, which maximizes the productivity and quality of mushrooms during the summer.

“Cold Range” Fruiting Temperatures: ~7-20C (44-68F). This strain of Shiitake will expand your season by fruiting earlier in the spring and extending later in fall than the wide range variety. Does not respond well to forced fruiting in summer.

“Wide Range” Fruiting Temperatures: ~15-25C (59-77F).This strain can be fruited over a wide range of temperatures, though mushroom quality and yields of this variety will be diminished in high heat as compared to the warm temperature variety.

“Warm Range” Fruiting Temperatures: ~13-27C (55-80F). During warm summer months, this variety produces mushrooms of better quality and higher yield than the wide range variety. May fruit naturally or by force in warmer spring and fall months, must be forced to fruit in summer.

Most cultivated mushrooms are grown on “hardwood” logs from deciduous trees. Preferred tree species in Canada are oak, maple, alder, birch, and beech. Typically the denser the wood, the longer the wait for your first crop of mushrooms, but thereafter you will enjoy crops for ~5-7 years. Fast-growing trees like poplar will produce mushrooms quickly (as soon as 6 months) but have a shorter production life (~3 years).

Gourmet edible and medicinal mushrooms that can be grown on hardwoods include Pearl Oyster mushrooms, Yellow Oyster mushrooms, Shiitake, Lion’s Mane, Turkey Tail and Reishi. For advanced growers wanting a challenge, try growing Maitake and Chicken of the Woods (hardwood variety).

If you have access to a log from an evergreen tree like fir, you can experiment with growing Phoenix Oyster, Bear’s Head, Hemlock Reishi and Chicken of the Woods (conifer variety).

Cedar trees have strong antifungal properties and therefore are not good for mushroom growing. Fruit trees are reportedly not very productive, but you can always experiment!

Some sources recommend waiting 2 weeks after cutting a living tree to allow time for natural anti-fungal compounds to dissipate before inoculating. Other sources report that this wait is not necessary and have shown that you can successfully inoculate immediately.

That said, it is important to inoculate within a month after falling the tree in order to give your fungal mycelium a chance to establish within the log before wild competitors have time to invade the log.

Having been down for years, this log would not be a good candidate for edible mushroom cultivation. Although it may not be visible, any logs left over several months or more will have already been colonized inside by wild fungi. If you then inoculate with Shiitake, Oyster or another mushroom of your choice, your mushroom will be competing for space (food resources) in the log.

You might still have success producing some mushrooms, however for best results start with logs from healthy trees that are freshly cut or fallen.

That said, if the log is there and you love to experiment, oyster mushrooms would be the best choice to plant because they grow very quickly and aggressively. Another good candidate would be Turkey Tail, a beautiful medicinal fungi which sometimes be found fruiting in the wild on older logs that have lost their bark.

The ideal time to cut logs is late winter for early spring inoculation. This maximizes time for the mycelium to grow into the log before the winter freeze. However, you can inoculate throughout the year, and it is generally best to plug your log within 2-4 weeks of the tree falling.

Fall is an awkward time, and you need to make a call whether to inoculate now or let the logs sit through winter and inoculate early spring.

If the weather in your location is already below zero, there would be no harm to let the logs sit through winter, as there is little chance of wild fungal competitors invading your log during this time. If you did choose to inoculate, your mushroom mycelium won’t have much opportunity to grow from the plugs into the logs either, and may be compromised by extreme cold.

If you anticipate a month or more of above zero daytime temperatures, or you can place your logs in a basem*nt or greenhouse that will be warmer than outside, then there would be an advantage to inoculating immediately and giving the logs a head start.

You may choose to keep different varieties of mushroom logs separated for log management purposes, but it’s not critical.

If your logs are physically touching, eventually fungal mycelium may grow out of one log into another. Traditional Shiitake cultivation in Japan was done by simply stacking freshly cut logs touching colonized Shiitake logs!

With that in mind, if you stack your freshly inoculated logs touching mature mushroom logs of another species, you might end up with two different mushroom varieties inhabiting and fruiting from the same log. Not what you intended, but kind of cool. Multiple fungal species growing from one fallen tree happens regularly in nature.

If logs are not touching, there is little risk of cross-contamination. Spores (mushroom “seeds”) travel long distances by air currents and will land on your log from your nearby mushroom crops and distant wild fungus. However, your planted mushroom species has a strong competitive advantage and there is little chance that other mushroom species will take over from spores.

Keep in mind that the logs you inoculated may have already been infected with a wild mushroom species, growing unseen inside. This wild fungus may coexist sharing the resources of the log, or one may outcompete the other. Since some wild mushrooms are poisonous, it’s important to accurately identify the mushrooms you harvest as the edible species.

After inserting your plug or sawdust spawn, we recommend covering the inoculation site with melted wax. This prevents contaminants from entering and retains moisture while the fungal mycelium grows into the log.

Many types of wax can be melted and used to cover inoculation sites. We sell soy wax for this purpose, but bees wax and cheese wax can also be used.