Growing Shitake and Oyster Mushrooms on Logs and WNC Mushroom Cultivation Community Resources

Thanks to the support of Cooperate WNC who provided mushroom spawn and tools and to David Warfel who coordinated our December 2024 workshop and stewarded the resources, we were able to host a Mushroom Log Cultivation workshop at Herron Cove this week and it was a wonderful success!

We inoculated over 80 shitake and oyster mushroom logs on the day of the workshop and still have more to go, for ~150 poplar, oak, cherry, maple and even sourwood logs that had fallen during the catastrophic Hurricane Helene. The logs incoulated were divided up between workshop participants, Herron Cove, Bountiful Cities Gardens (including the Lucy Herring Elementary Peace Garden) and the workshop facilitator David.

This project is one of the many examples of how WNC is staying strong through this unprecedented natural disaster.

In the mushroom log workshop we covered the basics of growing mushrooms on logs including:

• Log Selection & Preparation
• Inoculation from Hole drilling through packing and sealing the logs with wax
• Post-inoculation storage and harvesting

Read on to learn how it all works and for resources from the workshop!

How to Inoculate Mushroom Logs and Grow Mushrooms Outside

Growing shitake and oyster mushrooms on logs is actually pretty straightforward! It’s also more or less the same for any other mushroom that grows well on logs. But it’s worth noting that not all mushrooms can be grown on logs! Some grow better in prepared beds, bags in controlled environments, on cow dung, or are just difficult to cultivate all together. Much could be written about these, but in this case shitake and oyster mushrooms and many others are quite simple to cultivate on logs. If you’re curious about what other mushrooms you can grow on logs, just check the table linked below for more on other mushrooms that are easy to grow on logs.

To grow shitake and oyster mushrooms on logs, step-by-step you basically need to:

1. choose appropriate logs for your spawn and make sure they’re in good condition
2. drill the right sized holes in the logs at the right spacing
3. pack the holes with either sawdust or plug mushroom spawn
4. seal the holes
5. store the logs in a suitable location
6. monitor the logs for fruiting mushrooms
7. harvest your mushrooms!
8. tend the mushrooms periodically to support harvest and repeat!

But that’s just an overview though, here’s the details of what you need and how to do it 🙂

What do you need to make mushroom logs?

While you may be able to get away with not having specialized tools beyond a drill with the right bit, there are a few particular things which can really make things easier, especially if you’re working at scale.

• suitable logs (see How to select logs for growing mushrooms)
• mushroom spawn (that is a match for the logs you have)
  • Sawdust Spawn OR Plugs
• a drill or angle grinder with the right bit and/or attachment – for drilling holes
  • make sure your bit size matches your plugs or spawn inoculation tool size
  • a corded power tool is ideal for a large number of logs
  • an angle grinder with a specially designed log inoculation drill bit is the king of speed when it comes to mushroom log plug drilling – just get the right size for your spawn type
• tools for packing the spawn
  • either a sawdust spawn inoculation tool OR a hammer or mallet for plugs
  • for sawdust spawn you may be able to get away with a funnel and dowel, or even your fingers, but it will be much slower going
• suitable wax – unscented, not bees wax
  • Cheese wax, or “plug wax” doesn’t need melting, which can be handy, but also may come off more easily
  • a way of melting the wax if your wax needs melting – a slow cooker, rice cooker, or double boiler method is usually ideal
• a brush or tool for spreading wax
• pallets or other logs to store your logs on
• you may also need a chainsaw to cut your logs to size unless your logs are already cut to the right size.
• Tables for the drilling, packing and waxing process are sometimes helpful but you can easily do it on a tarp or even the ground.
• a tarp or other off-the-ground storage may be useful for short-term storage before and after the inoculation process – just to keep the logs off the ground
• you may also want labeling implements. Many folks use metal tree labels so that markers or paper labels don’t rub off. Labeling logs will help keep them straight.

That’s about it!

How to select logs for growing mushrooms

When selecting logs for growing mushrooms there are a number of things to consider. Log quality is one of the most important factors when growing mushrooms.

The goal is to have a log that does not have other competing mushrooms, and is ready for the spawn the setup shop and grow, and will go on to protect the mycelium as it grows inside the logs. Additionally, logs which were cut at different seasons have more or less ‘food’ for the mushrooms to consume, and will perform better.

The most important factors to consider are:

1. The type of tree
2. When the logs were cut
3. How they were stored once cut
4. The condition of the bark and wood
5. Size of the logs

What types of logs do are good for oyster and shitake mushroom logs?

Thank you to Field & Forest for sharing their wonderful information on log selection. If you’d like to see what types of logs are good for other mushroom types or prefer a visual table, you can visit their mushroom log selection page here.

When should you cut wood for mushroom logs?

How far in advance do you need to cut your mushroom logs?

Cut your mushroom logs with enough time to cure: that’s usually at least 2 weeks before you plan to inoculate if you’re cutting from living trees. Logs must be sufficiently dead and lack the living trees protective mechanisms before the mycelium can make a home there. Some logs may take longer, and having dried out enough to be dead is the key factor. Some logs types like maple may benefit form as long as 5 months or more! (Thanks Mushrooming Together for sharing your experiment!)

Ideally cured logs have small cracks due to drying, but not large cracks. If logs are left more than 4 weeks and they aren’t a high moisture content wood, they may need to be soaked before inoculating.

If you have trees which fell due to storm, and and they haven’t been laying on the ground, they may be able to cure in the air.

Logs which have been sitting for longer than 2 weeks may need soaking depending on their log type. If they are much longer, they may no longer be viable.

If you can’t time things right, cou can inoculate with less ideal cure times, but it’s very likely to impact mushroom yield.

What’s the best season to cut mushroom logs in?

The best time to cut logs for mushroom harvesting is during the dormant season before the buds swell. During this time, the trees have stored their sugars and minerals in the wood for winter and haven’t yet sent it out to the buds.

If you cut your logs during other seasons it’ll probably work, but you’ll likely get less life and less quality harvests out of the logs.

You should also cut logs for living or recently felled trees. If the trees have been standing dead, or have dead parts on them those parts are unlikely to be effective hosts for mushroom logs.

How should you store wood that you will use for mushroom logs?

After you cut your logs, you should keep them off the ground and otherwise away from risk of contamination by mushroom mycelium.

If logs lay on the ground, mushroom mycelium and other contaminants may get into the logs and compete with your desired mycelium impacting the quality of your harvests.

Can I use a log with broken bark or dead wood for mushroom logs?

Generally, no you should not use logs with significantly damaged bark or wood for mushroom logs. Small damage to bark can be covered with wax to keep moisture in but dead wood or damaged bark is an issue both due to contamination before inoculation as well as moisture loss and contamination afterward.

What size logs should I use for mushroom logs?

Logs should be long enough to stack and light enough to carry. That means ~ hip height and probably not larger than 6″ or so. Too short or too thin will reduce yield.

A rule of thumb for log size is that each inch of wood will give you one year of mushroom production.

You can inoculate mushroom logs which are shorter or thinner, but it’s a questionable return on investment.

You can incoluate mushroom logs which are longer or fatter, but you run into issues with moving and storage. In some instances, you may also need to use creative methods for larger logs, such as the totem method in order to ensure sufficient insulation.

How to prepare logs for growing mushrooms

Once you have your logs, you’re ready to inoculate!

You’ll want to do all three steps at once more or less: drill, plug and seal.

It works best to setup your station so that you can either do a log at a time or make an assembly line.

You’ll want to think ahead and make sure you have everything on hand, including your melted wax!

Depending on your wax melting methodology or if you’re using soft cheese wax (which doesn’t need melting) you may want to setup a rice cooker or slow cooker, or double boiler in advance. If you melt wax directly in a pan you may need to tend it very closely so the wax doesn’t burn or even catch on fire.

How to innoculate mushroom logs

When you’re inoculating your logs, you’ll want to setup a good station. This is where the tables mentioned earlier might come in handy, but it can be done on the ground if needed – a tarp might be useful to prevent contamination.

Before starting the process with each log, you should inspect it and make sure it’s worth your time, effort, and spawn 🙂

How to drill mushroom logs

Get your drill or angle grinder setup. The specially designed log inoculation drill bit is significantly faster and easier to use it comes to mushroom log plug drilling – just get the right size for your spawn type. Corded appliances are recommended for high-volume log projects for speed and so you don’t run out of battery and find your self waiting around.

When drilling your holes you should be sure to:

1. Drill the correct diameter hold for your spawn – otherwise you won’t be able to pack the sawdust or span effectively
2. Drill to the correct depth for your spawn – too deep and there will be air gaps that may impact the inculcation quality and work process
3. Drill holes ~ every 6″ in an alternating pattern of rows. start ~6″ in from the end of the log. Drilling too many holes makes inefficient use of the spawn and requires more sealing.

How to pack the mushroom spawn

Get your packing tools, and get plugging!

If you’re packing, saw dust you’ll want to make sure that the hole plugged all the way to the bottom with no air stuck at the bottom and flush with the top.

If you’re hammering in plugs, take care not to damage the plugs uncessarily much, and ensure they are flush. If you smash the down heads on mushroom plugs, they may not go all the way in and air will get caught inside.

How to seal mushroom logs

Once you’ve inoculated a log, you need to seal it to keep the moisture in.

Hopefully you’ve already got your wax nice and melted. Go ahead an use a brush or dabber to dab the wax on all the holes. Cover any (hopefully small) breaks in the bark or branches that were cut off as well.

Just enough to cover the exposed wood/spawn is sufficient.

How to store mushroom logs

Short term mushroom log storage

Once you finish sealing your logs, you’ll want to continue keeping them off the ground, and also out of hot sun and dryness.

They can be stacked like firewood in the short term, but you’ll want to make sure they get spread out before they start fruiting.

You may also want to be sure to label them so you don’t get them mixed up with other types of mushroom logs, and so you know when these logs were inoculated.

If it’s cold, you may want to keep them warm (and moist) for the winter. In some climates storing them in a plastic bag in a basement may be needed to support the spawn growth. Extreme temperatures may inhibit mycelium growth in the newly inoculated logs and in extreme cases could kill the spawn.

Long term mushroom log storage

Long term you want keep the logs moist and shaded, but also keep them in a place where you’re likely to notice sprouting mushrooms!

They also want to stay off the ground to prevent competition with other mycilium (especially when they are new logs). Other logs or pallets can be used to raise them off the ground.

If your logs dried out a bit during short term storage, you can soak them before putting them in your log term storage. Especailly if the logs are older more cured. If they are less cured, soaking is less called for.

They can be stacked a bit like a log cabin – two across, with two more perpendicular and so one at a hight that remains stable. This will allow the fruited mushrooms to be harvested easily. If the logs are packed too tightly, then it can be hard to access the mushrooms.

How to harvest mushrooms on your mushroom logs

Mycilium take 6-12 months to fully colonize the log. You may see white fibers (hyphea) on the log (the ends most likely, if you did your waxing right), which is an indication that the log has been colonized.

Make sure your logs are in an easy to notice spot, so you know when to harvest. Be sure to check them after big rains, especially when the weather is warm as well.

Mushroom logs will often begin fruiting (primordia or ‘pins’ appear) a few days after ideal conditions (wetness) occur with the right temperatures. They are often ready to harvest about 5-12 days after those ideal condition appear.

It’s best to cut the mushrooms off with a sharp blade after the gills are exposed and while the caps are still concave.

If you wait too long you may get dry mushrooms, or they may get eaten by forest critters!

How to force a mushroom log to fruit

If your log is sufficiently colonized (usually 6-12 months from initial incoluation), you can force it to fruit by soaking it in non-chlorinated cold water (rain water, creek water, distilled, well water, etc) for 24 hours. If you only have tap water, you can let the tap water sit in an open container for at least a day for the chlorine to offgas.

After removing them from soak, you will likely see the beginning of mushrooms after a few days, and they’re likely to be ready to harvest in 5-12 days.

You can repeat this process after the logs rests for 8-12 weeks.

Resources

Handouts from the workshop

Guide to Growing Mushrooms on Logs by David Warfel

Table of ideal Mushroom and log types from Field & Forest

Local Resources for Tools and Spore

The Asheville Tool Library has sawdust spore packers and other mushroom plugging tools such as angle gridners and drills. They are an amazing nonprofit library of tools!

Sow True Seed sells ready to go mushroom kits and other individual supplies including spore and wax. They also carry Noth Spore Kits.

Online Stores for Tools and Spore

Field and Forest

North Spore

and there are so many more!

WNC Mushroom Cultivation Community

There are a number of mushroom growing communities in the Asheville and WNC area.

Sign up to get an invitation to the Mushroom Cultivators of Asheville Group on Telegram:

Cooperate WNC in the mutual aid organization that funded this and other mushroom workshops by providing tools and spawn. They don’t always do mushrooms – they do so much more!

Facebook: Asheville Mushroom Enthusiast – range of mushroom enthusiasm

Facebook: North Carolina Mushroom Group – mostly identification and finds