Learning how to grow mushrooms from scratch is a little bit like learning a magic trick. And yet once you have the basic skills and principles sorted out, it’s really very doable.
Cultivating mushrooms is an excellent way to vastly increase both the diversity and the nutrition of your homegrown produce. And conveniently, mushrooms can be grown in disused areas with little light, so they slot into a home food system without competing for the same space as your other growing projects.
Blue oysters, garden giants, enokitake, pink oysters, turkey tail, shiitake, reishi, pioppini—a whole world of mushrooms can be grown down the side of your house, the place where not much else grows, as well as in buckets in the empty space under the porch, under your stairs, or even under your couch. Don’t have much light? Mushrooms don’t mind. If they have a stable temperature to grow in and can be moved to a humid environment to fruit in, they’re happy.
As a bonus, home mushroom cultivation can be run mainly (or exclusively if you like) on common waste products—woodchips, coffee grounds, straw, cardboard, tree prunings and so on. The cost for setting up home cultivation can be very small, and once you get right into it, you can harvest all year round and each month can be packed with nutrient-dense mushroom goodness.
Don’t be put off by the technical ‘mushroom speak’. Generally, mushrooms are not well understood, but once you’ve got the fundamentals straight, the processes are straightforward. And then you’ll have a potential lifetime of mushroom harvests ahead of you to nourish and heal your family, to swap and share, and you’ll be able to teach others how to grow them as well.
Bring on the mushrooms.
Mushroom gardens are a great way to use up odds and ends of woodchips and any spawn that needs a home, as well as creating resilience in your garden with yet another periodic, seasonal food stream that needs little attention.
There’s also the input for outputs factor—considering what you put into mushroom gardens (a bunch of woodchips and some spawn) and what you get out of them (many flushes of tasty mushrooms, and then great compost at the end), it’s a winner of a technique.
The basic processes are the same as for any other mushroom cultivation. You want to build up a large quantity of actively growing mycelium in a suitable substrate. The easiest method is to inoculate a large quantity of minimally processed woodchips in situ with grain spawn.
Making A Mushroom Garden
You’ll need to find a good spot for your mushroom garden— somewhere that’s reasonably moist with dappled shade. Take advantage of places that are too shady for vegetable gardens. A blackberry patch or similar brambles makes a good choice (once you’ve removed the brambles, of course).
You will need:
- Corrugated cardboard to cover an area 2 x 2 metres
- Approximately 200 litres of pasteurised hardwood woodchips, prepared a week ahead using the pasteurisation/ fermentation method (see box)
- At least 5 litres of spawn (see following page)
- Remove the grass from a 2 x 2 metre area of ground (leave any small bushes).
- Cover the bare ground with a double layer of soaked corrugated cardboard. Cover the cardboard with a 5 cm (2 inch) thick layer of the prepared woodchips. Spread the spawn in a layer over the woodchips, then cover with another 5–10 cm (2–4 inch) layer of woodchips.
- Periodically water your mushroom patch to ensure the woodchips stay a little moist—the equivalent to 25 mm (1 inch) of rainfall per week is a good amount.
- Keep an eye on your mushroom patch. After a few months, the mycelium should have colonised the woodchips. When conditions are right for the mushroom species you are cultivating, they should begin to fruit.
Clockwise from top left: The finished mushroom garden; Fermented woodchips, ready to be used as substrate; Stropharia rugosoannulata; Cardboard, fermented woodchips and a box of woodchip spawn.
Woodchips from eucalyptus, willow, poplar, alder, maple, birch, ash or even fruit trees will all work.
What’s That Smell?
The fermentation process of the woodchips is the anaerobic organisms (that don’t require oxygen) eating the available sugars and producing waste products. This is a good thing, as it uses up some of the available sugars in the woodchips (less sugar = less contamination) and the waste products are toxic to aerobes. This is why it smells! The anaerobes are also eating the competition directly because the water causes spores of aerobes to germinate and then they are eaten by the anaerobes.
This technique will work well for smaller areas, too—just scale down the quantities accordingly. One square metre (11 square feet) is a good minimum size to work from.
Pasteurising The Woodchip Substrate
Compared to bucket or jar cultivation, you need a lot of prepared substrate for a mushroom garden—we’re not just talking about small volumes. We’re talking wheelbarrow- loads of woodchip substrate. Fear not, it’s entirely doable using simple tools and zero energy inputs.
This technique is a very low-tech hybrid pasteurisation/ fermentation method that prepares the woodchips while effectively drowning or smothering any microbiology that might compete with your mycelium. It was taught to Nick by Paul Stamets in the USA, and we now use it at home.
To use this technique, take the required amount of hardwood woodchips and submerge them in a big drum of clean water for a week. We use a garbage can lid that fits inside the drum and place a brick on top to hold the woodchips under the water. This will kill any aerobic (oxygen-breathing) microorganisms in the woodchips. During this time, if the woodchips are fresh, they will also begin to bubble and ferment.
After a week, and once you’re ready to make your mushroom garden, drain the woodchips, all in one go. Draining will flood the woodchips with oxygen, killing most anaerobic microorganisms. The woodchips are now pasteurised, and you’re ready to build your mushroom garden.
Good Species For Mushroom Gardens
- Stropharia rugosoannulata (king stropharia or garden giant). This is one of our favourite outdoor mushroom species. It loves to live with a rich diversity of microorganisms.
- Pleurotus eryngii (king oyster, boletus of the steppes). King oyster mushrooms are from the Mediterranean and can handle slightly drier conditions. They thrive in symbiosis with Eryngium sp. (sea holly) and other plants from the Apiaceae family, so plant some sea holly, fennel, parsley or angelica in the same garden.
- Flammulina velutipes (enokitake). Enokitake grow wild where we live. In the middle of winter, they grow on all kinds of stumps and they particularly like the pruned stems of our currant bushes.
Life Cycle Of A Mushroom
Mushrooms start off as spores, emitted from a mushroom much like seeds from a seed pod. When a spore lands on a suitable substance, it grows into a hypha—a little thread composed mainly of mycochitin, a similar substance to that which crustaceans use to make their shells. When two or more hypha grow near each other, they bond together and share their genes to produce mycelium, a large network of hyphae, looking a little like a branching web of delicate white threads or roots.
Different mycelium eat different things. Some break down whatever woody substances they can get close to. Some mycelium have special relationships with certain tree species, sharing sugars and other nutrients with plant roots. Some mycelium eat insects, or live within them. They’re truly embedded into every aspect of life on earth, in a range of symbiotic roles.
Once the mycelium has colonised and eaten as much of its chosen food as it can, and when conditions are right, the mycelium will start to form fruiting bodies in the form of mushrooms, to reproduce and extend its territory.
Mushrooms are incredible little pieces of life. They’re ‘anti- gravity’, meaning they’ll push upwards with uncanny force, through wood or soil or sometimes even asphalt in a bid to get up into the fresh air and the light, to spread their spores. Just a few days later, they’re rotted and gone.
Like peaches, mushrooms are a tasty, unprotected food— their mission is to be eaten. In the process of being knocked about, picked up or generally taken apart, their tiny spores spread near and far, in their millions, with some spores landing in just the right spot to begin the process of life all over again.
This is an extract from Milkwood’s latest book, Milkwood: Real skills for down to earth living by Kirsten Bradley and Nick Ritar (Murdoch Books 2018), RRP $45.00. Photography by Kate Berry and Kirsten Bradley. Illustrations by Brenna Quinlan. www.milkwood.net