Mycelium plugs on logs

Mycelium plugs are easy to use and give a very good result for any hobby grower! The largest advantages are that it is simple, that you don't need to use heat treatment and that the mushroom flushes will be more evenly spread through time. But how do you use spawn plugs?


  • freshly chopped piece of wood
  • electrical wood drill diameter 8 mm
  • bag of mycelium plugs
  • plastic covering for each log or for each bundle of logs


log selection

1. Substrate selection:

Take a freshly chopped piece of wood of at least 10 cm diameter length from a deciduous tree. It needs to be freshly chopped wood of a healthy tree, as you want the log to be completely non-infected by funguses at the time of inserting the plugs.

Soft woods like poplar will be infected by other funguses very fast, especially in summer or spring, when the wood is very wet and the ambient temperature is rather elevated. Don't leave them laying around for too long if you can avoid it. Harder woods like oak or beech are less of a worry if they stay on the floor for a few months before inoculation.

Wood which contains a lot of resin or tannin or oil is not suited for inoculation: no conifers, eucalypts, oleanders, nor tropical hardwoods!

  At this stage, it is beneficial to soak your logs overnight, so they contain a good percentage of water.

preparing the logs for mushroom planting

2. Preparation: Drill holes in the log, about 10-15 cm apart, of the same diameter of the plugs (8 mm). The amount of inoculation points depends on the type of wood you use and on the thickness of the logs and on your incubation variables. Harder wood, thicker logs, colder temperatures = more closely spaced inoculation points.

tapping the plugs in the holes

3. Inoculation: Insert a plug in each hole. Should you wax the holes off? It is not essential, although it helps. Waxing sometimes creates more problems than it solves, as people could wax at too high temperatures and kill the mycelium in the plugs. Make sure to be cautious and if you don’t wax: don’t worry, it should still work fine. There are a few exceptions to this rule: if you use spawn to inoculate logs or if you use older spawn or if your logs are getting old, it is better to wax off or tape off the holes.

incubation of logs in closed climate container

4. Incubation: Put the logs in a large plastic bag which is not hermetically closed and put it in a nice, warm and dark place at about 20°C until the mycelium has completely invaded your logs. The mycelium will also grow if you put the logs outside, but the process will be slower and in winter, growth may stop entirely. The incubation time depends on growing conditions, mushroom strain, type of wood and log thickness. Incubation for Pleurotus sp. (Oyster Mushroom), a fast grower, is between 3 and 6 months. For Lentinula edodes (Shii-take Mushroom) it is between 6 and 12 months. Both these incubation periods are calculated for indoor incubation, outdoors it will most likely be slower, as it will be very dependent on seasonal variables.

mushroom plugs harvest

5. Fructification:Put the logs outside, in a damp and shady place. A shadowy corner, or in the long grass will do just fine, but make sure the snails don't get to your harvest first! Your mushrooms will start coming up as soon as the climatic conditions outdoors are right. The image depicts a flush of Oyster Mushrooms, which do very well on logs, but we also produce plugs for Shii-take Mushrooms. See more details here.

You also have the option to induce fruiting manually by giving the logs a 'cold shock', i.e. give them a cold water bath for a few hours or, in the case of Shiitake, a 'mechanical shock' which means literally stomping the log on the floor. With Shiitake, only do this after the log is fully ripe. It should look completely brown (and some white) and the bark should be peeling off nicely. Stomp it too soon and you'll get less mushrooms.