Using plug spawn to grow mushrooms for years!
Updated: Aug 25, 2019
Plug spawn is an easy way to start growing mushrooms at home, and one of the best ways to get mushrooms for a prolonged period. Some logs can produce mushrooms for years!
When creating inoculated logs with plug spawn we need 4 things.
- Plug spawn (Available on our website)
- A good log
- Drill and a 10mm drill bit
- Paraffin or other wax sealant (Available on our website)
After we have created the log we need to let the mycelium grow, and with the case of shiitake, choose when we want it to bear fruit. More on this will be explained at the bottom of the page.
Plug Spawn Plug spawn can be obtained through the Oak and Spore website. Plugs come in packs of 40 or 100, and come infected with Shiitake, Phoenix Oyster, or New Zealand native Oyster mushrooms. Shiitake is often the favourite to grow with plug spawn and you have more control over when you can get the log to bear fruit.
The plugs are short pieces of dowel about 9mm wide when dry, when wet and infected they expand slightly. The mushroom mycelium has grown over the plug, and its hyphae will dig into the fiber of the wood starting to digest it.
Log selection is very important, we cannot just choose any log to grow on, we need a wood that mushrooms really enjoy eating. Some wood have evolved a defence against mushrooms eating their wood, in the way of natural fungicides. Pine is known for the turpens, which prevent fungal growth, Walnut is also known for its juglone, which is another fungal inhibitor.
The good news is we have lots of trees in New Zealand which mushrooms just love, some mushrooms even share the same name as the trees they grow on! Below is a list of the good and the bad.
The good wood
Oak (the best for shiitake)
Poplar (Poplar mushrooms like growing on Poplar trees!)
The bad wood
There are some exceptions to the bad list for some specific mushroom varieties, but for growing at home lets just avoid them!
We want to choose a long that's between 40cm to 1 meter long. The shorter the log the harder it will be to keep moist, and the more we will have to water it.
We want the diameter about 12-20cm. obviously the larger the wood the more plugs we need.
40 plugs will roughly inoculate a 1 meter log.
Wood age The wood needs to be fresh cut, ideally within 2 months of inoculation. If the wood is too old the moisture content will have dropped and the mycelium won't grow very well through it!
Drilling holes You need a power drill with a 10mm drill bit. You want to drill 6cm deep holes in a line down the wood with about 15cm spacing between. Once you have a line of hole, rotate the wood 1/4, and put in another line of holes, staggered so they are spaced evenly. The more dowels you use the faster the colonisation of the wood will be.
After the holes are drilled we want to lightly tap 1 plug into each hole with a hammer. Once they are in flush we drip a bit of melted paraffin over the hole to seal out any competing fungi which might ingress and compete with the mycelium.
Storing the log Once the log is inoculated and sealed with paraffin, we can select a good spot for it to allow the mycelium to colonise. We need a shady damp spot that doesn't get too hot. Direct sun will quickly dry the log and stop the mycelium growth.
The best spot is a patch of ground that never really dries out that much.
If the wood piece is long, we can dig a whole, and bury 1/4 of the log in the ground, standing it upright. This will allow the log to suck up moisture from the ground.
If the log is short we can find a damp spot and cover it with some hessian sack.
If you are in a dry climate, you'll want to ensure your log stays damp. This can be done by watering it on a hot day, placing a plastic bag over the log to stop moisture evaporating and create a high humidity zone, or we can cover it with a sack and water it often so it holds a barrier of water around the log.
Fruiting the log
After about 4-6 months the log will be nearing it's time to fruit. Oyster will be ready to fruit well before Shiitake. Oysters could provide fruit as soon as 2 months after inoculation, so check regularly.
Shiitake colonise slower, so you'll generally be waiting 6 months. After 6 months we can signal the shiitake to fruit for us by taking the log, and submerging it in water for 24 hours. After this we take it out of the water and drop it onto the ground (not concrete) from about waist height. This will 'shock' the shiitake into fruiting. After the submerge and drop, place the shiitake log upright in its original spot and wait to see if you get some shiitake!
Shiitake will grow in flushes. After each flush they need a month or two to recover. after the recovery period you can shock the log again and get more shiitake!
Temperature for fruiting
Shiitake love the cold. If it's the height of summer it might not fruit. You want to shock your log into fruiting when the temperature is between 8-18 degrees during the day.
Check your logs regularly, you need to keep them moist, and you never know when some mushrooms will pop up!