Wine cap: the mushroom that feeds your vegetable bed

Of all the species we sell, one has nothing to do with logs or grow blocks. The wine cap, also called king stropharia or garden giant, grows in a bed of wood chips. Right on the ground, between your vegetables or under the shrubs. It is the species we recommend to anyone with a garden and no drill, and April is exactly the month to build the bed.

What does it look like?

Big. A mature specimen has a cap of ten to sometimes thirty centimetres, wine red to reddish brown, fading to yellowish brown with age. The gills underneath start greyish white and turn the purple-grey that gives the mushroom its Dutch name. Around the sturdy white stem sits a thick ring with a wrinkled top, and that ring is the best identifier. Young specimens, cap still domed and gills still pale, taste best.

Why is this the mushroom for the vegetable garden?

Because it improves the soil while it grows. The mycelium digests the wood chips within a season into dark, crumbly humus, keeps the soil beneath moist and cooperates with the roots of nearby plants. Gardeners who lay a wine cap bed between the cabbages or under the beans see the soil visibly change within a year. The mushrooms are the bonus, the soil is the reason.

How do you build a bed?

1. Pick a shady spot of at least a square metre. Under shrubs, between tall vegetables, on the north side of a fence. Part shade works, full sun does not.
2. Get fresh hardwood chips: from the council, a tree surgeon or your own chipper. No conifer, and preferably no chips that have been heating up in a pile for months.
3. Build layers. Loosen the soil, lay five centimetres of wet chips, scatter half the spawn over it, another five centimetres of chips, the rest of the spawn, and a covering layer of a few centimetres. One 250 gram pack covers roughly a square metre.
4. Water and cover. Give the bed a generous watering can and lay some cardboard or straw on top for the first weeks against drying out.

When can you harvest?

A bed built in April produces its first mushrooms from June or July in normal weather, and continues into October. They come after rain, often in waves, and grow fast: from button to full size in three to five days. Harvest young, while the cap is still domed, by twisting the stem loose at the base. A large specimen with a flat cap and dark gills is still edible but less tasty and attracts slugs.

What does it taste like?

Firm and earthy, with something people describe as potato or red wine. Unlike an oyster mushroom, this is one for the oven or a lidded pan: fried in thick slices, in a stew, or stuffed like a portobello. Short, hot frying works less well because of the thickness. Always eat cooked, never raw.

How do you keep the bed alive?

Feed it. Every spring, add a fresh layer of chips on top and the mycelium creeps in and carries on. A well-kept bed lasts for years and slowly spreads; if you like, move a few handfuls of colonised chips to a new spot in autumn and you have a second bed there the following year. In dry spells, soak the chips thoroughly once a week. Beyond that the fungus needs nothing. We know no species that gives back so much for so little work, which is exactly why it should not be missing from any garden with a shady corner.