Outdoor Mushroom Growing Pt 1 - Making a Woodchip Bed

This is the first in a series of blogs about outdoor mushroom growing.

Mushroom beds can be a great alternative to conventional veg growing. Often you can use patches of ground that aren’t suitable for much else, such as in between raised bed, behind sheds or around the base of fruit trees. As well as suppressing weeds, the mycelium enriches and develops otherwise poor or depleted soil and of course, you get to harvest delicious, naturally grown mushrooms.

The beehives looking beautiful in the summer, but the weeds and grass soon takes over

Here at Fruit Bodhi HQ we keep bees, and for ages keeping down the grass and weeds between and under the bee hives was a real pain. Then a couple of years ago we had the idea to turn the apiary floor into a woodchip King Stropharia (Wine Cap) bed. It worked brilliantly – almost no grass and weeds, but instead lots of wonderful mushrooms growing under and in between the hives. Boosted on by that success we decided to expand the woodchip bed which this blog will talk through.

Later on we will try out some other outdoor growing methods using logs and stumps - but more of more of that in a later blog. This one is about establishing a woodchip bed.

First step was to prepare the ground. We decided to double the size of the bed. We had to shift the beehives (which the girls didn’t like much) and then laid cardboard over the area we are using. We got rid of any big clumps of grass and weeds, but tbh we could probably have left them. The cardboard acts as a barrier to anything growing through.

As we tidied up under the beehives we found lots of really healthy mycelium from before, so that part of this bed is going to have a real head start.

Really healthy mycelium from the original bed, 2 years ago

To keep things tidy, we got some long ash poles to border the area. Strictly speaking that was probably not necessary, but we figured that something to retain the wood chip when we laid it would be a good idea.

Ash poles laid as a border to retain the woodchip once it's laid

A local tree surgeon dumped a good load woodchip for us. You need hardwood chip – never conifer. Get chips made from the heartwood and sapwood – not just a load of bark – and it must be fresh. If it is much more than a few weeks old, you might find other fungal species beginning to colonise it – and you don’t want that competition. However, live trees naturally produce anti-fungal defences, so the woodchips should be at last a week old, after which time that natural defence has disappeared. These chips were freshly cut the day they were delivered, so we left the pile for a week and half before using them.

Good quality, fresh, hardwood chips.

When you come to lay the bed the cardboard needs to be well watered. Luckily, we got help from the Somerset weather and didn’t need to hose it much, but if it’s dry, saturate your cardboard first. We sprinkled King Stropharia sawdust spawn onto the cardboard in small islands. In his excellent book Organic Mushroom Farming and Mycroremediation, Tradd Cotter recommends this method as it encourages the mycelia to branch out to find and join forces with each other.

Next, we added 2 or 3 inches of the woodchip, raking it out and packing it down. We gave this layer a light watering too. Tradd Cotter recommends putting down another layer of carboard or newspaper at this stage. When we laid our original bed 2 years ago we didn’t do that and it worked fine. But this time we gave that technique a go on half the bed to see if it makes a difference. We left the apiary side and did the carboard/paper layering on the other section.

We layered up spawn (always sprinkled in islands to encourage spreading) and then extra card/paper/woodchips – always making sure each layer was moist as we don’t want things to dry out. If you are worried about a bed drying out, a final layer of leaf litter or more wood chip will help retain the moisture.

The mushroom bed laid on the left, next lay the bed under the beehives

Now we are going to sit back and watch things. The bed should be fully colonised in a few months and we should be harvesting delicious wine cap mushrooms later this year. And it will be surrounded by gorgeous wildflowers come the spring and summer. A great place to relax and take in nature.

Now that Ophelia and Otis are getting mobile, we also decided to fence around the beehives – so you will see that going on in the videos and photos. It isn’t directly related to the outdoor growing project, but it does show that a mushroom bed (which will eventually turn into a single organism) will grow beyond normal garden barriers if the substrate and conditions are right.

You can get really high quality spawn from our shop. Tom makes the spawn more or less to order, so get in touch with us on info@fruitbodhi.co.uk if you want to discuss lead times.