How to grow oyster mushrooms on gorse

There are plants most farmers curse under their breath, and gorse is one of them. It scratches, spreads, and refuses to leave when forced. Yet in the right light, and with the right mindset, it begins to tell a different story. Beneath the armour of thorns is a plant doing honest work.

What if, instead of fighting it, we learned to work with it? Because sometimes the thing that gets in the way is the very thing that shows us a better path forward.

Not that we would advocate planting gorse, yet for those already contending with it, a different perspective is worth considering. Within syntropic agroforestry, gorse has long held a more favourable reputation than it does in most farming conversations. It is, in many respects, a remarkably hardworking pioneer species, stabilising degraded soils, fixing nitrogen, and creating sheltered microclimates where more vulnerable plants can establish. Push through an older stand and it is not uncommon to find young whau, karaka, mahoe and other native species quietly regenerating beneath its protective canopy.

Seen through this lens, gorse can become a useful ally rather than a persistent adversary. When managed syntropically, strategic pruning stimulates soil life, builds organic matter, and, with management and interplanting of cropping trees, begins to shift land often dismissed as wasteland into something far more productive.

The challenge, of course, lies in context. On grazing land, where gorse can dominate entire hillsides, syntropic management is not always the most immediately practical option. Faced with dense infestations, many landholders see little choice beyond repeated cutting or blanket herbicide application.

But for some, like us, those conventional responses have never sat comfortably as an option. Rather than accepting spraying or constant suppression as the only viable approach, my Dad, Klaus from PermaDynamics, began asking a different question more than two decades ago:

“What else could gorse be good for?”

Klaus had long been fascinated with growing mushrooms, particularly oyster and shiitake, and as a permaculture practitioner he was always looking for substrates that could close loops within the farm system. Mushroom growers traditionally use hardwood sawdust, straw, or agricultural waste streams.

But what if a rampant weed could transform into a nutritious food source? After a discussion with a colleague and dear friend Lenart Prinz from Prinz Mushrooms, Dad set off to try this new idea.

The first attempt

The first experiment didn’t begin particularly gracefully.

Sceptical that gorse would work at all, Klaus started cutting some down. Anyone who has harvested gorse has experienced the discomfort, and by the time he was feeding branches through the chipper his patience was wearing thin. His sleeves were scratched, the thorns were finding their way through his gloves, and he was thoroughly unimpressed with the whole process.

He cursed the gorse and swore he’d never do it again.

Still, the experiment was underway, so he finished one small batch of substrate and inoculated it with oyster mushroom spawn.

Then he waited.

About a month later, the results were undeniable. The bucket erupted with oyster mushrooms. Cluster after cluster appeared, far more abundant than expected.

Gorse, it turned out, was an excellent substrate. Its woody fibres provide a perfectly spongy structure. As it does not have true leaves, the spines of the gorse contain just enough nitrogen to nourish the mycelium, but not so much that it would cause mould as other leafy substrates might. The carbon to nitrogen ratio in gorse, in other words, is ideal mushroom food.

Much more motivated now on the second attempt, Klaus approached the job differently. This time he geared up properly – leather welding gloves and jacket, and a better sense of humour about the process. Instead of resenting the gorse, he embraced it as a partner in the system.

The work became enjoyable.

How to grow oyster mushrooms on gorse

Commercial mushroom farms use controlled growing rooms, air-conditioned systems, single-use plastic bags and gas sterilisation. That produces consistent yields, but it is resource-intensive. Our approach aims for a closed loop, where each element serves several functions and the by-products feed back into the farm.

1. Harvest the gorse. Cut close to ground level. Younger stems chip more easily and make excellent substrate. An electric chainsaw works well; handsaws are fine for smaller batches.
2. Chip the material. Feed the branches through a chipper to create coarse wood chips.
3. Pasteurise. Place the chipped gorse in hot water at 65 to 75°C for one to two hours. This suppresses competing fungi and bacteria while allowing beneficial organisms to remain. A longer soak is not recommended.
4. Drain thoroughly. Allow the chips to drain until they’re moist but not dripping. The leftover liquid makes a fantastic nutrient-rich fertiliser for gardens.
5. Keep things clean. Once pasteurised, keep the substrate off the soil and protected from rain to minimise contamination.
6. Mix in spawn. Per 20L bucket of substrate, mix in roughly 3–5% grain spawn by volume – about two generous handfuls works well. For beginners, buying your spawn in is recommended.
7. Add gypsum. A small handful per 20L bucket helps keep the substrate loose and improves mineral balance.
8. Clean the buckets. Wash the buckets and lids with wood ash and water, then give them a light spray of iodine solution to remove mould.
9. Prepare the holes. From the inside, cover the drilled holes (40–50mm wide around the bucket) with ideally a piece of cardboard or tape. This keeps the substrate from drying out during colonisation and keeps out pests.
10. Fill the buckets. Pack the substrate gently – firm but not compressed. Good airflow inside the substrate helps the mycelium spread without going anaerobic.
11. Incubate. Place the buckets in a shady, sheltered space (a garage works well). Over the next three to four weeks, white mycelium will spread throughout the substrate.
12. Maintain humidity. In hot, dry weather, occasional misting may help, but generally the substrate contains enough moisture on its own.
13. First flush. Around a month later, the first clusters of oyster mushrooms should appear through the holes, digesting the cardboard as they grow. Harvest them while the caps are still slightly curled downward.
14. Continue harvesting. Buckets can produce several flushes over a few months, depending on conditions.
15. Recycle the substrate. Once production slows, the spent substrate becomes excellent spongy mulch, compost material, or bedding for animal systems where it absorbs manure and urine before returning to the soil.
    
    
    

A new relationship with gorse

And that, in a rather large nutshell, is why we’ve grown even more fond of gorse.

Instead of seeing it purely as an invasive nuisance, we’ve learned to view it as an ally, a soil builder and a food crop waiting to happen.

Every time we harvest another stand, chip the branches, and watch the mycelium quietly transform thorny brush into clusters of edible mushrooms, it’s a reminder of one of permaculture’s most well-known perspectives: the problem is often the solution.

With a little creativity and a shift in attitude, even one of our nation’s most despised plants can become a regenerative source of nourishment.

And once you’ve tasted fresh oyster mushrooms grown from gorse, the next round of harvesting gorse suddenly seems like a very good idea indeed.

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For a full video showing how we do this, along with hundreds of other videos on using plants to build fertility and grow food in a low-impact way, join the PermaDynamics Membership. Grain spawn from Prinz Mushrooms:

This story first appeared in On the Land. Four issues a year, delivered to your door. Subscribe here.