25, 50 or 100 plugs: how many do you actually need?
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Our plug spawn comes in packs of 25, 50 or 100, and the question that always follows is: how many do I need? The answer depends on your wood, but luckily the maths is simple. Here it is, with a table for the most common situations.
The rule of thumb
Use roughly as many plugs per log as the log is centimetres thick. A log of 25 cm across gets about 25 plugs, a hefty 40 cm stump can take 40. That automatically lands you on the spacing we use in our instructions: holes every 15 centimetres, in a diamond pattern around the log.
That spacing is not a law. More plugs mean the mycelium occupies the wood faster and leaves less room for wild fungi. Fewer plugs can work too, it just takes longer, and the risk of something else hijacking the wood grows with the wait.
Worked examples
| Your wood | Advice |
|---|---|
| 1 log, 1 metre long, 15 to 20 cm thick | 20 to 25 plugs |
| 1 solid log, 1 metre, 25 to 30 cm thick | 25 to 35 plugs |
| 2 one-metre logs, around 20 cm | 50 plugs |
| Fresh tree stump in the garden, 30 to 40 cm | 40 to 50 plugs |
| 3 to 4 logs or a pile of thick pruning wood | 100 plugs |
In short: 25 plugs cover a single decent log, 50 cover two logs or a large stump, and with 100 plugs you can inoculate a small grove.
Can you put too many plugs in a log?
No. Mycelium from different holes grows towards itself and fuses into one network, it does not get in its own way. The only limit is practical: at some point you are drilling away more wood than you keep. Beyond the rule of thumb plus half, extra plugs mainly buy speed, not a bigger harvest. Harvest size is set by the volume of wood, not by the number of plugs.
Can you inoculate with too few plugs?
You can, and sometimes it works. But below ten plugs on a serious log it becomes a gamble. The mycelium has to conquer a large volume of wood from a few points, and every extra month that takes is a month in which airborne fungi attempt the same thing. If you want to save money, choose a shorter or thinner log rather than fewer plugs per log.
What do you do with leftover plugs?
Store leftovers in the fridge, in their closed packaging. They keep for months there. Handy when you inoculate a log in March and stumble on a beautiful stump in April. Just mind the species: every log stays a single-species project, so leftover shiitake plugs wait for fresh oak or beech, not for the neighbour's willow.
Does it differ per species?
The pattern does not, the patience does. Fast species like the common oyster mushroom forgive generous spacing, slow species like shiitake and reishi benefit more from full coverage because they are on the road longer. When torn between two quantities: go bigger for slow species, smaller is fine for oyster.
Still unsure about your particular pile of wood? Send us a photo with something for scale and we will do the sums with you. Happy to help.