Grow your own mushrooms

00:38, Sep 03 2010
FUNGUS FRUIT: Heather Cole, owner of Mapua Country Trading Co, shows off shiitake inoculated dowels used to grow mushrooms on logs.

Gardeners tired of growing standard greens and looking for something a bit more adventurous might want to consider growing mushrooms at home, as Vanessa Phillips reports.

If a garden was like a fashion house, growing your own mushrooms would be right on trend.

In his book Jamie at Home, British chef Jamie Oliver writes about growing mushrooms in the home garden via various methods, including buying special mushroom-growing kits. In a recent episode of River Cottage, television chef Hugh Fearnley-Whittingstall also featured a segment on growing your own mushrooms.

Mushrooms have plenty of health benefits and can be expensive to buy in shops, and yet many of us in New Zealand don't forage for or grow our own at home – perhaps because it's thought of as hard, or because of concerns about correctly identifying safe mushrooms to eat.

However, as the owner of the Mapua Country Trading Co, Heather Cole, points out, while it's important mushrooms gathered in the wild are correctly identified as safe before being eaten, growing your own edible fungi isn't that difficult. In fact, with some varieties it's downright easy.

Mrs Cole has long had an interest in growing mushrooms at home, bolstered by living and travelling overseas and enjoying mushrooms in other cultures.


"As a gardener you're always seeing weird and wonderful stuff coming up in your garden and you think, `Ooh, can I eat it?'.

"As a country we don't really know that much about mushrooms," she says. "We don't eat mushrooms like they do overseas. In Japan the variety of mushrooms that are propagated – you can go into these mushroom markets and there's just amazing different types of mushrooms growing in these huge big tunnel house markets. They are as important as salad greens are to us."

Mrs Cole said growing mushrooms with proper spore in pasteurised conditions is important, so that "you're not just picking whatever comes up on the front lawn, because there are some fairly noxious mushrooms in New Zealand".

Mapua Country Trading Co has had a shop open in Mapua for two years, selling gardening-related goods, but has existed as a mail order business for the past three years.

Mrs Cole has sold mushroom-growing kits since starting the business and says that recently there's been a lot of interest in growing mushrooms at home. Logs with shiitake mushrooms blooming on them, which Mapua Country Trading Co. displayed at the Ellerslie International Flower Show in Christchurch in March attracted plenty of attention, and at last weekend's Ecofest in Nelson there was strong demand for the variety of mushroom-growing kits the business stocks.

Mapua Country Trading Co currently sources its kits for button/flat and oyster mushrooms ($39.50 per kit) and shiitake mushrooms ($29.50) from Rawene mushroom grower and authority Tim Thornewell.

Mrs Cole has tried growing mushrooms from each of the kits, but says the one that works for her best is the strong flavoured shiitake "because it's a sort of set and forget mushroom and I like that".

The button and flat, and oyster kits, while delivering faster results than the shiitake, are more hands-on and require more tending and keeping the humidity right, Mrs Cole says.

The shiitake, which are grown on logs, take longer to fruit but will produce mushrooms for many years, she says, and the mushroom spores eat the wood as it rots. "They'll fruit for seven to 10 years. As the log rots they'll just keep coming out."

To grow shiitake mushrooms with the kit you need freshly cut logs of non-resinous wood such as willow, alder, poplar or fruit trees like cherry, cut into sections about 30-40cm long and 20cm in diameter.

Woods like pine or gum are too resinous to use and the logs need to be freshly cut "because you don't want a log that's home to other fungal organisms".

"Harder woods like oak and beech will last longer but they take longer to fruit so it's horses for courses." Holes have to be drilled into the logs and mycelium-inoculated dowels supplied in the kits are then tapped into those holes. The holes are capped off with candle wax or beeswax, and the logs should be heaped up in leaf mulch in a cool, shady, moist place in the garden.

Mrs Cole keeps hers under her low-branching macadamia trees.

"In summer I water mine a wee bit, too, just to make sure they don't dry out."

It usually takes at least six months for the shiitake spores to travel through the log before they'll be ready to fruit. Shiitake fruit naturally on the logs in autumn and spring but the mushrooms can be brought on by soaking the logs in a bucket of water and resting them in a cool place.

Mrs Cole collects about 1 1/2 to 2 cups of mushrooms from each log per picking. One shiitake kit has enough dowels for about five logs.

Button and flat mushrooms, by comparison, grow in a compost (provided in the kit) and need to be grown in humid conditions with a temperature range of 12-14 degrees Celsius, but away from bright light, Mrs Cole says. Garages and laundries are often good places.

Button/flat mushrooms will fruit in flushes over a one to three month period but you have to collect spores to keep them going beyond the kit's life, she adds.

"Mushroom growing isn't difficult," Mrs Cole says. "It's just different."