Mushrooms are not vegetables—they’re fungi, a separate kingdom of organisms with their own biology and growth requirements. This distinction matters for how you cook them, understand their nutrition, and grow them at home. At Adi’s Urban Mushrooms, I grow gourmet varieties in West Norwood by working with fungal biology rather than plant botany, and that difference shapes everything from flavour to texture.
What makes mushrooms fundamentally different from vegetables?
Vegetables come from plants—leaves, roots, seeds, or fruits—and plants make their own food through photosynthesis using sunlight. Mushrooms belong to the kingdom Fungi, which is neither plant nor animal. They don’t photosynthesize. Instead, fungi break down organic matter (wood, straw, compost) and absorb nutrients from it. A mushroom is the fruiting body of a much larger organism called mycelium, which lives in the growing medium beneath the surface. When I cultivate gourmet mushrooms here in South London, I’m feeding the mycelium with the right substrate—often straw or hardwood sawdust—and creating the right humidity and temperature for it to fruit. That’s fundamentally different from growing a lettuce or carrot.
This biological difference has real consequences. Vegetables typically need light, soil nutrients, and a long growing season. Mushrooms need darkness or low light, the right decomposing material, and much faster fruiting cycles. I can grow several harvests of oyster or shiitake mushrooms in the time it takes to grow a single tomato crop. The mycelium’s ability to convert substrate into nutrition also means mushrooms can grow in spaces where vegetables cannot—on shelves, in dark corners, even under the stairs. That’s why I teach cultivation workshops at the Community Mycology Lab in Remakery Brixton: people are surprised to learn that a small corner of a kitchen or bedroom can produce fresh gourmet mushrooms year-round.
Why does calling mushrooms ‘vegetables’ matter in the kitchen?
In culinary terms, mushrooms behave more like vegetables than they behave like animals protein, but they’re chemically distinct. Vegetables are mostly water and carbohydrate, with cell walls made of cellulose. Mushrooms are also mostly water, but their cell walls are made of chitin—the same material that makes up insect exoskeletons. This means mushrooms cook differently. They don’t soften and break down the way a carrot does; instead, their texture becomes tender but retains a pleasing firmness and bite. When I cook with fresh gourmet mushrooms at West Norwood Feast, the umami flavour that emerges (from amino acids like glutamate) is far more savoury and meat-like than any vegetable can deliver.
Nutritionally, mushrooms offer something vegetables don’t: they are a rare plant-free source of vitamin D (when exposed to sunlight), contain all nine essential amino acids, and offer compounds like ergothioneine that are found in very few foods. They’re also lower in carbohydrates than most vegetables and contain no starch. This makes them valuable in diverse diets, but it also means treating them as a vegetable substitute in a recipe often doesn’t work. A mushroom isn’t a replacement for a tomato; it’s a different ingredient that adds depth and umami to a dish. Understanding that distinction changes how you cook.
How do grocery stores and restaurants classify mushrooms?
Despite their biological classification as fungi, mushrooms are almost universally shelved, sold, and served as vegetables in the UK food system. Supermarkets stock them in the vegetable aisle. Restaurants list them on vegetable plates or sides. Food regulations treat them as produce for health and safety purposes. This is a practical convention, not a scientific one. It exists because mushrooms fit into the culinary and retail space where vegetables live, and because most consumers expect to find them there.
What’s useful to know is that this classification varies slightly depending on context. In nutritional labelling, mushrooms are often grouped with vegetables for simplicity, even though their nutrient profile is distinct. In the produce trade, fresh mushrooms are handled as perishables alongside leafy greens and root vegetables. When I work with local restaurants or sell at West Norwood Feast, I always emphasize what makes each variety unique—a king oyster mushroom’s meaty texture, a shiitake’s earthiness, a button mushroom’s delicate flavour—rather than treating them as interchangeable with other produce. That transparency about variety and provenance is part of how I work here in South London.
What does this mean if you want to grow mushrooms at home?
The fact that mushrooms are fungi, not plants, changes everything about growing them yourself. If you’ve ever tried to grow a tomato or lettuce, you already know that plants need light, outdoor space (or a sunny windowsill), and time. Mushroom grow kits—which I produce and sell—work on completely different principles. A kit contains mycelium already colonized onto a substrate. Your job isn’t to plant seeds and wait for growth; it’s to mist the kit with water and maintain the right humidity. A mushroom kit will produce its first flush of mushrooms in days or weeks, not months. You don’t need soil, fertilizer, or sunlight. You do need patience with understanding the lifecycle of fruiting bodies, consistent misting, and the right temperature range.
This is why I run cultivation workshops at the South London Mushroom Club and through corporate events: growing mushrooms requires you to think like a mycologist, not a gardener. You’re creating conditions for a fungus to fruit, not nurturing a plant to grow. Once you understand that shift—once you see the mycelium as a living network and the mushroom as its fruit—growing at home becomes accessible and rewarding. People who couldn’t grow vegetables in a dark London flat can suddenly produce fresh gourmet mushrooms on a shelf. That’s the real power of understanding what mushrooms actually are.
How should you treat mushrooms differently in storage and cooking?
Because mushrooms are fungi with chitin cell walls, not plant cells with cellulose, they respond differently to storage and heat. Mushrooms are best kept in a paper bag or breathable container in the fridge, not sealed in plastic, because they’re sensitive to moisture and will rot if trapped in condensation. They don’t wilt the way lettuce wilts; they darken and become slimy. They also have a shorter shelf life than most vegetables—typically 3–7 days depending on variety. Fresh gourmet varieties I grow, like oyster or shiitake, are best used within days of harvest for the best texture and flavour.
In the pan, mushrooms benefit from high heat and generous space. Because they’re mostly water, crowding them will cause them to steam rather than caramelize. I slice them, spread them in a single layer, and let them cook hard until they begin to brown and release their moisture. The umami compounds become concentrated as the water evaporates. They’re also forgiving to overcook compared to vegetables—mushrooms won’t turn to mush. Understanding their fungal nature helps you treat them with respect in the kitchen: they’re not a vegetable to soften and break down, but a protein-rich ingredient with its own distinctive behaviour.
The bottom line: why the distinction matters
Mushrooms are fungi, not vegetables, and that biological fact shapes how you cook them, grow them, and understand their place in food and nutrition. But in everyday life—in supermarkets, restaurants, and kitchens across the UK—they’re treated and sold as vegetables, and that’s a useful practical convention. The key is to hold both truths at once: respect their fungal nature when you’re growing or cooking them, but don’t get caught up in rigid classification when you’re trying to use them in a meal. What matters most is understanding how mushrooms actually behave, what flavour and texture they bring, and how to work with their distinctive properties. That’s what drives my work here in West Norwood—growing varieties with real character, teaching people how fungi actually work, and helping you get the best from these remarkable organisms.