Mushroom Madness Part 3: Cultivation Techniques

So you’ve decided you want to grow mushrooms, you’ve learned a little bit about the kingdom Fungi and their role in the ecosystem, and now you want to know how to grow them. Well you’re in luck, because Part 3 is all about easy, small-scale cultivation! 

While there are many ways to grow mushrooms- and in fact, different types of mushrooms will require different techniques and conditions- we will focus here on three relatively simple methods for growing mushrooms outdoors at home or in a small commercial setting. Those methods are Logs, Totem, and Wood chips. We’ll explore how to set up each of these systems, maintenance and care, and the advantages of each. Stay tuned!

Shiitake mushrooms growing on hickory logs

Before we really get into it, we need to talk about spawn. We briefly mentioned spawn in last week's episode, but it’s worth taking a deeper dive, as spawn is the starting point for all of the methods that we will cover today; and indeed the starting point for just about all methods of mushroom cultivation.

As we learned last week, the mushroom proper is only the reproductive organ of the fungus; most of the organism exists as a network of cellular filaments called mycelium in the soil, wood, or other substrate. This mycelium is capable of regrowing from even small fragments that break off and find their way into another place, whether carried away by a squirrel burying a nut, or by a human intentionally cultivating the fungus. 

Spawn is a substrate that has been fully colonized by the desired fungal species that we use to inoculate our fruiting substrate, or the thing from which we want mushrooms to grow out of. The most common substrates for spawn are sterile sawdust, grain, or wooden dowels/pegs, however next week we will look at some experimental methods of non-sterile spawn.

Spawn is a substrate that has been fully colonized by the desired fungal species that we use to inoculate our fruiting substrate

We use spawn because it is healthy, clean, and vigorously growing, which allows us to scale up a small amount of a healthy culture into a large amount of fruiting substrate that can produce lots of mushrooms for us to eat!

SPORES AND SPAWN ARE NOT INTERCHANGEABLE! Spawn is like a 5 year old grafted apple tree, while spores are like the pollen from a single flower. If you were trying to plant an orchard (mushroom farm), starting from established trees (spawn) would be much faster and more likely to succeed than starting from pollen (spores).

There are many online retailers where you can buy high-quality spawn. I have only good experiences with Field and Forest. They have a wide selection and great customer service. You can also produce your own spawn at home with a pressure canner, as we do. We’ll outline that procedure next week. If you wish to purchase spawn from us, shoot us an email and see what we currently have in stock.

Okay, with that out of the way, let’s learn how to use spawn to establish a mushroom yard.

We’ll start with the log method, as this is the most common. This method is great for shiitakes and oyster mushrooms. For this, you’ll need to gather some fresh logs. The species of tree that you use will determine which kinds of mushrooms you can grow, and the types of mushrooms that you want to grow will determine which types of trees you should seek out. Field and Forest has a great chart on what wood to use for what mushroom.

Logs should be cut during the dormant season, ideally late fall after the leaves drop or early spring before the buds swell. This ensures maximum sugars are stored in the wood for the fungus to eat. For maximum yields, logs should be left to rest for at least one week before being inoculated to let the tree’s natural antifungal defenses break down, but should not be left for more than six weeks or other organisms can move in and contaminate the logs, and they can also dry out. If this is just a hobby, however, and not a commercial operation, then just use whatever you can get whenever you can get it and don’t stress too much about it.

Once you have your logs, you can drill holes to fill with spawn. We recommend spacing holes at approximately 4-6 inch spacing in a diamond pattern all around the log. More spawn will not necessarily increase yields, but it will speed up the time it takes for the first flush of mushrooms to be produced. Too little spawn, however, could allow for contamination to take hold in the log, which could result in significant reductions in yield. 

If doing only a few logs, a standard power drill is fine, but for many dozens of logs or more, we recommend using an angle grinder with drill attachment. Field and Forest sells a great angle grinder kit.

With the holes drilled, it’s time to fill them with spawn. This can be done with clean hands and a spoon, with a special inoculation wand (shown below), or with a hammer for peg spawn. Once all the holes are filled, a little bit of wax is applied to seal in the moisture and keep the spawn from drying out while it makes its way into the wood.

After that, the logs get labeled with the type of mushroom they were inoculated with and the date of inoculation, then stacked in a shady place for the spawn to colonize the logs. We call this phase the Spawn Run. Once the spawn run is complete, you should start to see mushrooms popping out periodically as the weather permits!

Another variation on the log method that requires no tools is to simply make a stack of logs and stuff the spawn in between the logs. The pile can then be covered by some leaves to retain moisture, and mushrooms will pop out as they feel appropriate. This method has worked for us, but is a bit more experimental, so we will cover it in more detail next week.

Oyster mushrooms growing out of a log pile via our experimental log pile tek.

The totem method is similar to the log method, but uses thicker diameter logs and doesn't require the drilling of holes. It works great for oysters, lion's mane, and turkey tail.  For this method, logs are cut into ~1ft sections and stacked into a totem, with spawn stuffed in between the sections like a sandwich. The totems joints then get wrapped in some scrap plastic to retain moisture during the spawn run, and are then unwrapped when it’s ready to produce mushrooms.

The last method that we’ll talk about today is cultivation on wood chips. This method works great for winecap mushrooms, but does not work well for oysters or shiitakes. For this method, winecap spawn is spread along the ground, sometimes on top of a layer of cardboard, and then covered in a layer of wood chips, about 4 inches thick. Only hardwood chips should be used for this method, as winecaps do not grow well on conifer wood. In our experience, the winecap fungus grows best at the interface between soil and woody debris, so exceptionally thick layers of wood chips can sometimes stifle growth. Winecaps can be very productive, and they can planted anywhere you put mulch, like in garden pathways or around the base of fruit trees, and don’t require the shade that the log methods do!

So now you know how to grow mushrooms in a variety of methods including logs, totems, and wood chips! These are tried and true methods that have a high degree of success, but can require expensive tools and higher energy consumption to produce. In next week’s installment, we will look at some less proven, more experimental methods of mushroom cultivation including non-sterile spawn generation, encouraging naturalization of fungi in the landscape, and a deeper look at the log pile method discussed above. This is an open area of research and opportunities for collaboration are abound! So stay tuned and please reach out if you’d like to be a part of this ongoing experiment!

See you next week!