Why February and March are the best months to inoculate logs

Early February marks the start of our busiest weeks of the year. Not because there is anything to harvest, but because the next month and a half decides how every log of this year will turn out. The question we get asked most often is simple: when should I inoculate my log?

The short answer: in February or March, on wood that was felled two to six weeks earlier. That is not tradition or habit, there are three hard reasons behind it. I will walk through them below, along with what you can still do if you are running late.

Why is winter wood better for mushrooms?

In autumn, a broadleaf tree pulls the sugars out of its leaves and stores them in the trunk and branches. A tree felled between November and February is therefore packed with stored food. That food is exactly what your mycelium needs to colonise the wood.

Fell the same tree in June and a good part of that energy sits in the leaves and the sap flow. The wood is wetter, poorer and spoils faster. It can still work, but you hand your mushroom a head start it will never claw back.

Fresh wood has no tenants yet

The second reason is competition. In nature, dead wood never stays empty for long: spores of ink caps, crust fungi and moulds you have never heard of drift through the air all year round. In winter and early spring that spore pressure is at its lowest.

Inoculate in February or March and your species gets a log that is still almost clean, plus a few months of head start before the competition wakes up. That is the whole race: the species that occupies the wood first usually keeps it.

How long can wood sit before you inoculate it?

Two to four weeks after felling is ideal, six weeks is just about acceptable. Straight after felling the wood is still full of natural defences, so give those a little time to fade. Wait months, however, and the wood will have dried out while the first wild fungi moved in.

Not sure about a log that has been lying in the garden for a while? Look at the cut ends. If you already see discolouration, black lines or fuzzy patches, the log is taken and is better off as firewood.

Can you still inoculate in April or May?

You can, and it will not fail outright. But every week later means less growing time before winter. A log inoculated in March can be largely colonised by October. A log from late May goes into winter only half colonised, which leaves it vulnerable to frost and drying out.

If you are late, pick a fast species. The common oyster mushroom is the sprinter among wood-loving fungi and forgives a lot. Shiitake is slower and more particular, that one really deserves an early start.

What about autumn?

Autumn inoculation is done, but we advise beginners against it. The mycelium gets a few weeks at most to establish before soil temperatures drop, and a half-colonised log in winter is an open invitation to everything else that likes living in dead wood. Better to store your plugs somewhere cool until February, they handle that fine.

The inoculation season in practice

This is how we plan it ourselves, and it works the same way in an ordinary garden:

• November to January: arrange your wood. Ask around during pruning season, or check with a tree surgeon or your local council for fresh logs of beech, oak, birch, alder or poplar.
• February and March: drill holes (8 to 10 mm), tap in the plugs, seal them with the wax that comes with your order.
• April to October: lay the log in the shade and keep it moist during long dry spells. Nothing else to do.
• Next year: depending on species and log thickness, the first mushrooms appear after 6 to 18 months.

Every order of plug spawn ships with instructions covering drilling distances and the wax method step by step. Questions about your own log? Just drop us a message, that is what a nursery is for.