Mushrooms do not have seeds. They reproduce through microscopic spores released from gills, pores or other surfaces on the fruiting body. These spores are fundamentally different from plant seeds: they’re single cells without a protective coat, and they require specific conditions to germinate. Understanding this distinction is essential if you’re growing mushrooms at home or considering a cultivation workshop.
How do mushrooms reproduce if they don't have seeds?
Mushrooms are fungi, not plants, and their reproductive biology is entirely separate from seed-bearing plants. Rather than seeds, mushrooms produce spores—single-celled structures released in vast quantities from the underside of the fruiting body. In button mushrooms and many gourmet species like oysters and shiitake, these spores sit on thin structures called gills. When mature, the mushroom releases billions of spores into the air. A single mushroom cap might shed more spores in a day than there are grains of sand on a beach.
This reproductive strategy has worked for hundreds of millions of years. Spores are lightweight and can travel on air currents, water droplets, or on animal fur and feathers, dispersing the fungus far and wide. Once a spore lands on a suitable substrate—decaying wood, straw, compost, soil—and conditions are right (moisture, temperature, darkness), it germinates and begins growing as mycelium, the fungal equivalent of roots. The mycelium is the real organism; the mushroom we pick and eat is simply its fruiting body, like an apple on a tree.
What's the difference between spores and seeds?
Seeds and spores are so different that comparing them is almost misleading. A plant seed contains an embryo, stored nutrients, and a tough, protective coat. You can store seeds dry in the cupboard for years and they’ll remain viable. Spores are single cells with no embryo or stored food. Most fungal spores are fragile, short-lived, and highly sensitive to drying out. A mushroom spore can’t survive years of storage the way a tomato seed can.
Reproductively, a seed carries genetic material from both parent plants (if sexual reproduction occurred). A fungal spore in many common cultivars actually carries genetic material from only one parent, because many gourmet mushroom species have evolved to reproduce asexually through spore production alone. This is why when you harvest oyster mushrooms from the same substrate, the next flush of mushrooms is genetically identical to the first—they’re clones, all descended from the same mycelial colony.
Why can't you grow mushrooms directly from spores?
You technically can grow mushrooms from spores, but it’s impractical for most home growers and professionals alike. A single spore must germinate and then grow as mycelium for weeks or months, slowly colonising substrate in the dark. During that time, competing moulds and bacteria can overrun your growing space. In a kitchen or small home setup, contamination is almost inevitable. Commercial growers and educators like myself work with spawn—grain or sawdust colonised by healthy mycelium—because it jumps past the slow, vulnerable germination stage and gets straight to the robust growth phase.
The workshops I run at the Community Mycology Lab in Brixton and the South London Mushroom Club focus on spawn-based growing for exactly this reason. Spawn is your insurance policy. When you inoculate straw or wood chips with spawn, the mycelium is already thriving and competitive, easily outpacing contaminants. If you’ve ever bought a grow kit, you’ve received fully colonised substrate, a step beyond even spawn, ready to fruit with just moisture and air.
How do commercial growers source new mushroom varieties?
While spores aren’t practical for everyday cultivation, they’re essential for developing new varieties and maintaining genetic diversity. Mycologists isolate spores in sterile laboratory conditions, culture them into pure mycelium, and then use that mycelium to create spawn. This is how new cultivars emerge and how breeders improve traits like yield, flavour, disease resistance or environmental tolerance. It’s meticulous work, far removed from a home grow kit, but it’s how the oyster, shiitake and wine cap mushrooms you buy at West Norwood Feast or local restaurants came into being.
Once a cultivar is established as pure mycelium, it’s multiplied through spawn production. A single laboratory culture might generate spawn destined for thousands of kilos of mushrooms. This keeps production efficient and maintains the quality you expect. When I source spawn for small-batch growing, I’m relying on growers who’ve done that isolating and culturing work—I focus on growing, cooking, and teaching, rather than reinventing the mycelium from scratch.
What does this mean for growing your own mushrooms?
The fact that mushrooms reproduce by spores, not seeds, affects your options as a prospective grower. You won’t buy mushroom ‘seeds’ at a garden centre. Instead, you’ll either buy spawn (which you mix into your own substrate), ready-colonised grow kits, or attend a cultivation workshop where you’ll learn the principles hands-on. If you want to try growing, a kit or a workshop session (we run these at the Remakery in Brixton) removes the contamination risk and lets you focus on understanding fruiting conditions: humidity, temperature, fresh air and light.
If you become serious about growing and want to experiment, you might work with spawn to inoculate straw, logs or supplemented compost. Understanding spore biology won’t change how you grow on a practical level—but it explains why spawn exists, why kits work, and why mushroom growing is fundamentally different from seed-based vegetable gardening. It’s also why mushroom cultivation can be faster (many species fruit within weeks of inoculation) but also more vulnerable to invisible contamination if conditions aren’t clean and controlled. Knowledge of this biology is what separates a lucky harvest from a reliable one.
Where can you learn more about mushroom growing?
If you’re curious about the detail behind mushroom biology and want practical experience, workshops and community projects are the clearest path. The South London Mushroom Club and Community Mycology Lab at the Remakery bring together growers of all levels to share knowledge. I also run cultivation workshops for individuals and corporate groups, where you’ll handle spawn and substrate, learn contamination prevention, and understand what’s happening biologically as your mycelium colonises and fruits. These aren’t theoretical—you’ll see and feel the process firsthand.
We also sell mushroom grow kits alongside fresh gourmet mushrooms at markets and through direct orders. A kit is an excellent starting point if you want to see fruiting happen in your home without the steeper learning curve of spawn work. Whether you choose a kit, a workshop, or spawn-based growing, you’ll benefit from understanding that mushrooms bypass the seed strategy altogether. That knowledge informs every choice you make and every result you achieve.