Cut your log fresh from a living tree in late winter, then inoculate it two to eight weeks later, ideally between late February and May. Cut it less than two weeks before and residual anti-fungal compounds in the wood can slow your spawn; leave it longer than eight weeks and rival fungi may already have moved in. Colonisation then takes 12 to 18 months, and most UK growers see their first flush in the autumn after that.

When is the best time to cut a log for mushroom growing in the UK?

In late winter, while the tree is dormant, and within two to eight weeks of when you plan to inoculate. The two conditions go together. A dormant log gives you the best wood, and cutting it close to inoculation keeps it clean until your spawn goes in.

The bark matters more than most first time growers expect. It is the log's skin, holding moisture in and competing fungi out for the years your mycelium needs. A log cut in July, in full leaf and full sap, bruises and sheds bark far more readily. Dormant wood also carries more stored sugars in the sapwood, which is what your mycelium feeds on.

What you should not do is cut in the autumn and store the log until spring. A log sitting in the open for months is colonised by wild fungi long before your plugs go in, which is the exact problem the two to eight week window is there to avoid. If you have bought a kit ahead of the season, store the plugs in the fridge and cut the log fresh nearer the time.

Choose a healthy living tree, not deadwood off the woodland floor, and take a log you can lift, since you will be stacking and possibly soaking it. Oak and beech are slow to colonise but crop longest. Birch and alder colonise quickly and finish sooner.

Why do you wait between felling and inoculating?

A freshly felled log still has live defences in the wood. Give it a couple of weeks and those fade, letting your spawn take hold cleanly. Leave it too long and the opposite problem arrives: wild spores land on every exposed surface from the moment the saw comes out, so after a couple of months in the open your 30 plugs are joining a fight rather than taking empty ground.

The working rule, then: cut fresh, rest the log two to eight weeks, and inoculate within that window. Not the same day, and not next autumn. Our full method for drilling, plugging and sealing is set out in how to grow mushrooms on outdoor logs, worth reading before you pick up the drill.

Not every log will do, so it is worth knowing which logs are best for growing mushrooms in the UK before you cut.

What should you be doing each month?

November to January: planning and sourcing. Line up a healthy tree, order your kit and store the plugs in the fridge. Do not cut the log yet. A log needs inoculating within two to eight weeks of felling, so cutting now and waiting for spring would leave it too long in the open.

February to March: felling. Cut your log fresh while the tree is still dormant, the sap is down and the bark is tight. Cut it to a length you can handle and leave the ends alone, since you seal them at inoculation, not before. Stack the resting log off the ground on bearers, in shade and shelter, and count forward: inoculation is two to eight weeks away.

Late February to May: inoculation. Two to eight weeks after felling, drill with the 8mm bit in a staggered diamond pattern, tap in the plugs, then seal every hole and both cut ends with melted beeswax. The wax locks moisture in and spores out. Work on a mild, still day if you can, since rising spring temperatures get the mycelium out of the plug within weeks.

June to August: watering and shade. Nothing to do but keep the log alive. Site the stack in dappled shade, north or east facing if you have the choice, never against a hot south wall. In a dry spell, soak it.

September to October: first inspection. Check the cut ends. White mycelium creeping across the end grain is the sign you want, though nothing in the first autumn is entirely normal.

November to February, year two: overwintering. Leave it. Frost does not kill the mycelium, it pauses it. Keep the stack sheltered from drying winds and let winter rain do the watering.

Spring to autumn, year two: first flush. Most logs finish their 12 to 18 months here and produce. The trigger is usually a temperature drop after heavy rain, which is why UK first flushes cluster in early autumn.

What does a colonised log actually look like?

Ahead of schedule looks like white mycelium spreading across both cut ends by the first autumn, bark still firm, the log heavier than it looks. On schedule is patchier: a bloom of white on one end, nothing on the other, and no mushrooms through the first twelve months.

Behind schedule is dry wood with a hollow sound and loose bark. That is a moisture problem, not a spawn problem, usually fixable with a long soak. What you do not want is other fungi fruiting from the log. One or two brackets are common and rarely fatal, but a log covered in them has been taken.

What triggers a flush, and how long will the log crop?

Cold and water. A sharp drop in night temperature after a heavy soaking is the classic trigger, which is why autumn is the main UK cropping season, with a smaller flush often in late spring.

Once it starts, the log fruits for three to five years: modest in the first cropping year, strongest in the middle years, then tailing off as the sapwood is used up. When a log stops, it has been eaten, which is what was meant to happen. Growers wanting a harvest meanwhile run an indoor kit alongside. The mushroom growing kits category covers those, and they crop in days rather than months.

How does UK weather change the timings?

A dry summer pushes everything back, because mycelium stalls in dry wood. A drought year can add months to the 12 to 18 month window. A mild winter brings the opposite problem: a log ready to fruit but never getting the cold snap that triggers it. Those logs often flush heavily the moment the weather turns. In the south, expect the earlier end of every window. In Scotland and northern England, the later end.

Keeping a log going through a drought

Soak it. Fully submerge the log for several hours, or overnight for a large one, using a water butt, a trough or a builder's tub with a brick on top. If you cannot submerge it, run a hose over it slowly, then cover it with damp hessian for a day or two. A splash from the watering can does almost nothing, since water needs time to move into end grain. Signs a log needs it: bark lifting at the edges, cut ends pale and cracked, and the log lighter than when you stacked it.

Where should the stack sit through the year?

Summer wants shade, winter wants shelter, and one spot usually does both: under deciduous cover such as a hedge or a fruit tree, or on the shaded side of a shed, with bearers keeping the wood off wet soil. Avoid open lawn, hot walls and wind funnels. Leaning logs against a fence works well, as does a low crib stack, though a tight pile dries slowly, which helps in summer and can hold logs too wet in a wet winter.

Does the calendar change by variety?

The windows for cutting and inoculating stay the same across every variety. What changes once the log is colonised is the season each one fruits in, and whether it is a UK native. Both are worth weighing when you choose.

Beyond the season, the varieties differ in how they behave. White Oyster is among the quickest to colonise and often the first to give you something to pick. Shiitake and Lion's Mane on dense oak or beech sit at the longer end of the colonisation window, then crop reliably for years. Turkey Tail is a tough, leathery bracket fungus with fan shaped, banded caps, used for teas and decoctions rather than cooked, with a long history of traditional use, particularly in East Asia.

Because the fruiting seasons differ, running two or three varieties across separate logs spreads your harvests across more of the year. A Summer Oyster log for summer, a Shiitake for spring and autumn, and a Turkey Tail for autumn and winter cover most of the calendar between them. Since plugs are £8.00 each when ordering more than 2 of the same variety, most growers keep one variety per log.

What if you buy plugs out of season?

Put them in the fridge. Merryhill Mushrooms spawn plugs keep refrigerated for two to three months, which covers the gap between an autumn or winter purchase and a spring inoculation. Keep them in the packaging, in the main body of the fridge rather than the freezer or the door. Cold slows the mycelium without killing it, whereas plugs left warm for weeks start growing in the bag. Remember that it is the plugs you are holding over, not the log. Cut the log itself fresh, two to eight weeks before you plug it.

That two to three month window is why log kits work as presents. Someone opening a kit in late December has until roughly late February or March to get the plugs into a freshly cut log, which lands neatly in the inoculation season. Our gifting storage guide covers holding a kit safely before it is handed over, and the mushroom gifts range shows what pairs well with a log kit.

Worked example one: a winter gift, inoculated in spring

Sarah buys a Shiitake log kit in November for her father, adding the hand written gift note for £0.50.

November. The kit arrives. The plugs go straight in the fridge.

25 December. He opens it and moves the plugs to his own fridge that afternoon, giving him until roughly late March before the two to three month window closes.

Mid February. A neighbour takes down a birch. He takes two lengths he can carry and stacks them off the ground behind his shed. Cutting now, rather than back in December, keeps the log inside the two to eight week window before he plugs it.

Late March. Inoculation day, about six weeks after felling. He drills the staggered pattern with an 8mm bit, taps in all 30 plugs, melts the beeswax and seals every hole plus both cut ends.

July. A dry fortnight, so he submerges each log overnight in a water butt.

October, same year. White mycelium on the cut ends, no mushrooms. Correct for month seven.

Following autumn, month 18. After a cold, wet week, the first Shiitake push through the bark, at the later end of the window.

Worked example two: inoculated in spring, nothing by autumn

Tom plugged an oak log in April. By the following October, eighteen months on, he has seen nothing and assumes he wasted his money. Here is the order to check things in.

One, the ends. Mycelium on the end grain means the log is colonised and has simply not been triggered. Tom finds a good bloom on one end.

Two, weight and bark. His log feels light and the bark is lifting. Dry logs do not fruit.

Three, the wood. Oak is one of the slowest to colonise. Eighteen months is not late.

Four, the weather. A dry summer and a mild September, so no cold and wet trigger has arrived.

The fix. He submerges the log overnight, stands it in deeper shade and waits for a proper cold snap. His first flush comes the following spring, around month 24. Nothing here was failure. It was an oak log, a dry summer and a mild autumn stacking up.

What should you realistically expect in years one, two and three?

Year one: nothing visible. The work happens inside the wood. Your jobs are watering in dry spells and keeping the stack shaded.

Year two: the first flush, usually modest. Often a handful of mushrooms rather than a basketful, and usually in autumn. This is the year that proves the log took.

Year three: the log hits its stride. Fuller flushes, sometimes twice in the year, running on until the sapwood is spent.

Growers who give up do so in year one, almost always because they expected the timescale of an indoor kit. A log is a different proposition, and it repays you for years.

Frequently asked questions