How to Grow Maitake (Hen of the Woods): Bags and Buried Logs

Maitake, also called hen of the woods (Grifola frondosa), is one of the most rewarding mushrooms you can grow, and one of the most demanding. Unlike oyster mushrooms, which will fruit from almost any pasteurised straw, maitake is slow, fussy about temperature and fresh air, and varies a lot from strain to strain. A 2021 master’s thesis on maitake cultivation from the Swedish University of Agricultural Sciences describes it plainly as a difficult species with a narrow window of good conditions.

The good news is that there are two well-documented ways to grow it at home. The first is the indoor sawdust-bag method used by commercial farms. The second is the buried-log method, which is slow but needs little equipment once the logs are inoculated and can keep producing for years. This guide covers both, with the temperatures and timings published by researchers and specialist suppliers, so you can choose the route that suits your space and patience.

Before you start: what kind of fungus maitake is

In the wild, maitake grows at the base of hardwood trees, especially oaks. UMass Extension describes Grifola frondosa as a cause of root and butt rot in oaks, fruiting from late summer into autumn. In southern New England, its fruiting peaks between mid-September and early October. Michael Kuo’s MushroomExpert profile describes it as weakly parasitic and also saprobic, meaning it can keep living on wood after the tree has died. Its large, branched clusters typically measure 15 to 40 cm across.

That biology explains the growing methods. Maitake is a white-rot fungus that digests hardwood, so cultivated maitake is grown on hardwood sawdust or on short sections of hardwood log, most often oak. It also explains why it is slow: it builds up a lot of mycelium before it commits to fruiting.

If you want background on the mushroom itself, including its flavour and kitchen uses, read our maitake guide first. This article sticks to cultivation.

Choosing your method

	Indoor sawdust bags	Buried logs outdoors
Equipment	Pressure cooker or steam sterilisation, filter-patch bags, a humid fruiting space	Pressure cooker or large pot, autoclavable bags, a shady garden spot
Time to first harvest	Roughly 2 to 3 months under controlled conditions	Usually 3 months to 2 years after burial
Control	High: you set temperature, humidity, light and fresh air	Low: the weather decides
How long it produces	Usually one main flush per bag	Logs can fruit for 7 years or more
Best for	Growers who already run sterile sawdust blocks	Patient growers with a shady yard and an oak supply

For a general comparison of these two styles across all species, see our article on log growing versus bag growing.

Method 1: Growing maitake indoors on sawdust bags

This is the method used for commercial production and studied in most published research. It needs sterile technique, because the rich sawdust and bran mix that maitake likes is also an ideal food for moulds.

Step 1: Prepare the substrate

A useful reference recipe comes from a 2018 study by Song and colleagues in AMB Express, which used as its control formula:

75% hardwood sawdust
23% wheat bran
2% calcium carbonate (CaCO₃)
water to bring moisture to about 62.5%

The bran supplies extra nitrogen, and the calcium carbonate helps buffer acidity. In the same study, formulas that replaced part of the sawdust with corn cob gave higher yields. The best one reached a biological efficiency of 44.91%, compared with 32.42% for the control. Biological efficiency is the fresh weight of mushrooms harvested divided by the dry weight of substrate. Corn cob is not always easy to buy, so the plain sawdust and bran mix is a sensible starting point.

Step 2: Sterilise

Pack the moist mix into polypropylene grow bags with a filter patch. The researchers autoclaved their bags at 121°C for 85 minutes. At home, a pressure cooker at 15 psi reaches about the same temperature. Large or densely packed bags need extra time, because heat takes a while to reach the centre. Supplemented sawdust must be sterilised, not just pasteurised. Our explainer on sterilisation versus pasteurisation explains why.

Step 3: Inoculate

Once the bags have cooled completely to room temperature, add maitake spawn. The researchers used 10 ml of liquid spawn per bag. Home growers more often use grain spawn from a supplier. Work in front of a flow hood or in a still-air box. Seal the bags straight away. If you have never done sterile inoculation, practise first with a forgiving species such as oyster.

Step 4: Spawn run

Keep the bags in darkness at about 23 to 26°C (73 to 79°F). Song’s team held carbon dioxide (CO₂) below 3,000 ppm during this stage. The literature review in Dahlin’s 2021 thesis found an average spawn-run temperature of about 23°C. In one study it summarises, the spawn run took about 62 days.

The study kept bags in these conditions until primordia formed. Primordia are the small first growths of the mushroom, and they are the signal that the bag is ready to move on. Be patient here, because maitake usually takes much longer than oyster to reach this point.

Step 5: Move to fruiting conditions

This stage is where most home attempts go wrong, because maitake reacts strongly to stale air. The conditions used in the 2018 AMB Express trial were:

Factor	Spawn run	Fruiting
Temperature	23 to 26°C	19 to 21°C
Relative humidity	Not specified	93 to 97%
Carbon dioxide	Below 3,000 ppm	400 to 700 ppm
Light	Darkness	About 200 lux, 12 hours a day

Across the literature it reviewed, Dahlin’s thesis found a slightly cooler average fruiting temperature of around 17°C and humidity near 87%. It also cites recommendations to keep CO₂ at 500 to 800 ppm, because levels of 1,000 ppm or more tend to produce misshapen fruit bodies. In practice, outdoor air is roughly 400 to 450 ppm. So a fruiting space needs frequent fresh-air exchange, not just a sealed humid box.

To start fruiting, open or cut back the top of the bag above the primordia. Lower the temperature into the fruiting range, raise the humidity, and give the bag gentle, indirect light. A small fan feeding a humidified tent, or a shotgun-style fruiting chamber with plenty of holes, can work. A sealed tub with occasional fanning usually is not enough.

Step 6: Harvest

Harvest when the rosette has formed distinct, overlapping caps but before the edges thin out and curl. Twist or cut the whole cluster off at its base. In the Song study, the full cycle for the control formula, from inoculation to harvest, was about 63 days. Expect your own timing to be longer if your conditions are less tightly controlled.

Common problems with bag-grown maitake

Green or black mould on the block: usually a sterilisation or inoculation failure. Discard the bag outdoors without opening it indoors. Our contamination guide covers prevention.
Primordia that stall or turn into lumps without caps: often too little fresh air, too much CO₂, or too much warmth.
Long stems with small, cupped caps: a classic sign of high CO₂ or very low light.
Dry, cracked edges: humidity is too low, or a fan is blowing straight onto the cluster.
Nothing happens for weeks: some strains need a cooler drop, and some are simply slow. Strain choice matters, so buy from a supplier that says its strain is suited to indoor bags.

Method 2: Growing maitake on buried logs

This is the method mushroom pioneer Paul Stamets recommends, according to Dahlin’s review. It is close to how maitake lives in nature. Field & Forest Products, a long-established US spawn supplier, publishes the steps below.

What you need

Short sections of freshly cut, living hardwood, ideally oak, about 8 inches across and 11 inches long (about 20 by 28 cm). Cut them between late autumn and early spring.
Autoclavable bags with a collar and foam plug or filter, large enough for one log each.
A pressure cooker, a steamer, or a large pot.
Maitake sawdust spawn, about 1 to 1½ cups per log.
A shady outdoor spot with soil you can dig, ideally near hardwood trees.

Year-one timeline

Late winter or early spring: cut the logs and heat-treat them inside their bags. Field & Forest gives several options: pressure-cook at 10 to 15 psi for 60 minutes, steam for 3 to 6 hours, or boil for 1 hour. The goal is to give maitake a head start against the many fungi already living in fresh wood.
After cooling: add the sawdust spawn to each log inside its bag, then close the bag with the collar and plug.
Incubation, about 2 to 3 months: keep the bagged logs at about 55 to 70°F (13 to 21°C). They are ready when they are mostly white with mycelium, sometimes with orange patches.
By late June or early July: remove the bags and bury the logs upright in a shaded spot, with the top of each log about 1 inch (2.5 cm) below the soil surface. Space them so you can find them again, and mark each position.
Late summer and autumn: watch for fruiting. Some logs fruit in the first autumn, about 3 months after burial. Others take up to 2 years. Water the area in dry spells.

Buried maitake logs can keep producing for 7 years or more, according to Field & Forest, so a single afternoon of work can supply clusters for several autumns.

Why burial works

Burying the log keeps it moist and cool and gives a steady temperature. It also mimics the root zone of an oak, where wild maitake usually appears. The surrounding soil also provides the temperature drop of early autumn, which tends to trigger fruiting in nature. For a similar outdoor project with a different species, see our guide to growing shiitake on logs.

Wild hen of the woods rosette with grey wavy caps emerging from oak leaf litter — A wild hen of the woods fruiting from leaf litter. Photo: Geoff Swaebe via iNaturalist, CC0 1.0.

Cultivated maitake versus wild maitake

A garden bed with buried maitake logs will sit among other wild fungi. Some of them grow in similar clustered shapes. Kuo lists Meripilus sumstinei (the black-staining polypore) and Polyporus umbellatus as look-alikes. UMass Extension also mentions Meripilus. A cluster that comes up near your logs is not automatically one of yours.

Before eating anything that appears outdoors, confirm what it is, with an experienced local identifier if you have any doubt. A photo or a written description is not enough to decide that a wild mushroom is safe to eat. Indoor bags grown from a known spawn are far less likely to cause confusion, but you should still throw out anything that looks or smells wrong.

A realistic expectations checklist

Start with good spawn. Strain variability is one of the main reasons maitake projects fail. Ask the supplier whether a strain is suited to bags, logs or both.
Plan for slowness. Even under controlled conditions, published cycles are around two months for bags. Logs are measured in seasons.
Prioritise fresh air over extra humidity. Many failed indoor fruitings are caused by high CO₂ rather than dryness.
Keep records. Note dates, temperatures and what the primordia looked like. Maitake rewards growers who learn from each attempt.
Do one method well first. If you are new to sterile work, buried logs are more forgiving. If you already run supplemented sawdust blocks, bags are a natural next step.

Frequently asked questions

Can I grow maitake from a store-bought cluster?

Cloning a fresh cluster onto agar is possible for experienced growers. However, fruiting tissue from a supermarket pack is often old or contaminated, and you won’t know whether the strain fruits well. Buying a commercial culture or spawn is more reliable.

Can maitake grow on straw?

Maitake is a hardwood decomposer. Published cultivation work uses hardwood sawdust, often with bran or other supplements, or hardwood logs. Straw is not a standard substrate for this species.

Do I need oak?

Oak is the classic host and the wood most often recommended for logs. The AMB Express study used a general hardwood sawdust, and Dahlin’s thesis also lists beech among maitake’s natural hosts. Avoid softwoods such as pine.

How much will one bag or log produce?

Yields vary widely with strain, substrate and conditions, so treat any single number with caution. The 2018 study reported biological efficiency of about 32% for its basic sawdust formula. That means roughly 320 g of fresh mushrooms per kilogram of dry substrate under research conditions. Results at home are usually lower.

Sources and further reading

Featured image: maitake cluster by Jan Wegmann via iNaturalist (CC0 1.0). Inline photo by Geoff Swaebe via iNaturalist (CC0 1.0).

How to Grow Maitake (Hen of the Woods): Sawdust Bags and Buried Logs

Before you start: what kind of fungus maitake is

Choosing your method