Why not every mushroom can become a grow kit

Every autumn it comes round again: do you also have a grow kit for chanterelles? Or for porcini, or truffles? The answer is no, and not for lack of trying. The answer is in the biology. Mushrooms feed themselves in three different ways, and only one of the three can be packed into a bag of substrate. Understand that and you understand our entire range in one go.

The three ways a mushroom eats

The first group are the decomposers, saprotrophs in scientific terms. They live on dead material: wood, straw, leaves, coffee grounds. Oyster mushroom, shiitake, lion's mane, nameko, wine cap: all decomposers. The second group are the partners, the mycorrhizal species. They live in a trade with living tree roots: the tree provides sugar, the fungus provides water and minerals. Chanterelle, porcini, fly agaric and truffle belong here. The third group are the parasites, which grow on living plants or animals; little of culinary interest there, apart from honey fungus and cordyceps.

Why can you not make a grow kit from a partner species?

Because it cannot live without a tree. A chanterelle needs the roots of an oak, beech or pine, not as a place but as a partner. Without that exchange the mycelium grows on agar for a while and then stops. So you cannot put it in a block of sawdust, because there are no roots in there. That is also why shop chanterelles are always wild-picked, and why truffle farming means planting a wood and waiting ten years. Work is being done on it, especially in Scandinavia and Japan, but a chanterelle grow kit in a box exists nowhere in the world yet.

Which decomposers do work in a block?

In principle all decomposers, but not all equally well. A grow kit works when the species can do three things: colonise a block of substrate quickly, build up enough reserves in that block to fruit, and do so at living room or utility room temperature. The oyster mushroom is the champion here, which is why it is the best-known grow kit in the world. Lion's mane, maitake and reishi manage it too, with a little more patience. Shiitake can, but gives thinner caps on a block than on wood.

And why do we sell some species only as plug spawn?

Because they do better on a log, or because they refuse to fruit indoors. Velvet shank needs cold to fruit, and you cannot give it that on the kitchen table. Chicken of the woods grows slowly and wants the mass of a thick log to build a serious fruiting body. Wood ear prefers elder wood and does little in a block of sawdust. And split gill and turkey tail are tough wood fungi you do not eat like an oyster mushroom but dry and brew; they simply deserve a log. Plug spawn is not second choice there, it is the right form for that species.

So why does a species sometimes appear on someone else's website?

Because "grow kit" is a stretchy term. Packs of chanterelle spores are sold "to inoculate your garden", and the honest outcome of that is nearly always nothing. Morels are sold the same way, with a success rate we would not dare promise customers. We only put things in the shop that we have seen work in ordinary people's homes. That makes for a smaller range, and that is fine.

What might still come?

Among the decomposers there is room left. Species like king oyster, chestnut mushroom and pioppino do very well in a block and are on our list to test as grow kits. And cordyceps, a parasite that in cultivation can be persuaded to grow on rice, is the most unusual strain in the fridge, but that is where it stays: in the EU it may not be sold as food, see this piece. What is not coming is a chanterelle box. For that you have to go into the woods, and honestly, that is rather nice as it is.