How to grow your own mushrooms

We’ve seen a big demand for grow-kits and cultivation courses over the last couple of years. There’s really no excuse for not growing mushrooms if you have a garden. As well as producing a delicious crop, mushroom mulches (the layers of material in which fungi grow) keep down weeds, retain moisture and help build the soil to grow healthy plants.

There are various ways of growing mushrooms at home, but we’ll focus on mulches here. A good species to start with is the garden giant, also known as the wine cap or king stropharia. These are big, meaty mushrooms, delicious in stews, easy to culture and quick to grow (make sure to pick them before they get too big and lose their flavour).

Start in March or April to avoid the risk of frost. Choose a semi-shaded spot, ideally among fruit bushes or trees, which will benefit from the mulch. Get your hands on mushroom spawn. Spawn is a substance, usually grain, that’s been treated with the fungal culture or mycelium you need to grow mushrooms. We sell it but it is available from farms or grow-kit shops.

For the substrate, source two or three large cardboard boxes stripped of plastic and without too much ink; a couple of wheelbarrows of fresh woodchip (not more than a month old) containing more hardwood than softwood (call your local tree surgeons or landscape gardeners and ask if they have any); and a 1kg bag of straw, which you can get from a pet shop.

For 1.5kg of mushroom spawn, prepare an area of 1-2m2 for the bed. Dig out any persistent weeds. Cover the ground with a layer of cardboard and saturate with water, piercing holes in the cardboard where water is pooling. Cast a third of the spawn over the surface, making occasional small islands, then cover evenly with 3cm depth of woodchip and water lightly.

Create a second layer of cardboard, using smaller, torn-up strips, and thoroughly saturate. As before, cast the spawn and cover with 3cm of woodchip. Repeat the process to create a third layer. Finally, cover the bed with a layer of straw and water it once more thoroughly. Water every day for the first week, then every other day for the next three weeks, and once a month thereafter – unless there is enough rain.

After four to eight months, the mycelium should have grown through the woodchip. Keep an eye on the bed when fruiting conditions are good – at temperatures of 14-18C, often when sunshine has followed rain. The mushrooms will be ready to pick after 48 hours of appearing. (Be sure to properly identify your garden giant mushroom: it should have a thick white stem, a burgundy to brown cap, greyish gills and black spores.)

After two harvests, add a 5-10cm layer of woodchip before winter and cover with straw. You can do this for two-three years, after which it is best to make a new bed. You can easily propagate more beds by taking the myceliated woodchip from your original as your “spawn”. Or expand your horizons and try growing a different mushroom, such as oyster or wood blewits.

Growing Mushrooms in coffee grounds

When we first started growing mushrooms in coffee grounds back in 2011 we could see instantly why it made so much sense. You can take a massive waste stream and use it to grow gourmet Oyster mushrooms in a way that is easier than traditional mushroom cultivation. This article is an in-depth guide to growing mushrooms on coffee grounds. We’ll look at the benefits of growing mushrooms from coffee, and provide a step by step guide to the process so you can get stuck in and get growing too.

Why grow Mushrooms on coffee waste?

When a cup of coffee is made, less than 1% of the coffee biomass actually ends up in the cup. Think about that for a second… There are more than 9 billion kilos of coffee beans produced each year. After all the huge amount of energy in producing & shipping coffee beans around the world, all the value is placed on the liquid extract of their flavour. Of course, a cup of coffee is a truly wonderful thing. But the problem is that the other 99% of the biomass of the coffee bean is wasted. However, this huge amount of waste coffee is still packed full of nutrients which Oyster mushrooms love to grow on.

Who are GroCycle?

We are a social enterprise based in the UK and we’ve been growing mushrooms in coffee grounds since 2011. We were already growing gourmet mushrooms in our local area back then, and came across the idea of growing on coffee waste on the internet and in mushroom growing textbooks. At the time Back To The Roots had just starting making mushroom growing kits from coffee waste in the US (they since dropped using coffee after admitting they were no good at mushroom growing and outsourced their production to another company!). Gunter Pauli from the Blue Economy had been promoting the idea too as a great example of a circular economy business model. We were really inspired by the prospect of growing our mushrooms on this widespread waste material so we switched our whole production to growing on coffee grounds. A year later we set up one of the world’s first urban mushroom farms in Exeter, UK.