Greenhouse Gardening in the UK: What Works, What Doesn’t
When you think of a greenhouse, a structure with transparent walls and roof used to grow plants in controlled conditions. Also known as glasshouse, it’s one of the most practical tools for extending the growing season in the UK’s unpredictable climate. But here’s the thing — not every greenhouse is built the same. In the UK, many gardeners use unheated versions, not because they can’t afford heat, but because they don’t need it. Hardy plants like winter lettuce, kale, and hardy perennials do just fine without a heater, as long as they’re protected from frost and wind. The real advantage? You get earlier spring starts and later autumn harvests without the energy bill.
What’s often confused with a greenhouse is the glasshouse, a traditional British term for a glazed structure, often made of glass and timber, used for growing tender plants. While some people use the terms interchangeably, glasshouses are usually more permanent, more ornate, and often attached to a house. Then there’s the polytunnel, a flexible, plastic-covered tunnel structure used for crop production — cheaper, easier to install, but less insulated. Each has its place. If you’re growing tomatoes or peppers, you’ll want something with decent insulation and ventilation. But if you’re just trying to protect your strawberries from slugs or get a head start on brassicas, an unheated greenhouse or even a cold frame does the job.
One of the biggest mistakes UK gardeners make is assuming they need to heat their greenhouse. They don’t. In fact, many of the most successful growers in Britain rely on passive solar gain — letting the sun do the work. A south-facing greenhouse with good thermal mass (like stone or water barrels inside) can stay 10°C warmer than outside on a cold winter day. That’s enough for parsley, chives, and even some varieties of strawberries to keep growing. The real challenge isn’t heat — it’s airflow. Stagnant air leads to mildew, rot, and pests. That’s why ventilation, even in winter, matters more than a thermostat.
And what do you grow in it? The posts below cover exactly that. You’ll find which flowers bloom in an unheated UK greenhouse through winter, which fruit varieties are best suited to British conditions, and how to avoid common mistakes like overwatering or poor soil. There’s also a deep dive into the British word for greenhouse — why we call it a glasshouse — and how that history shapes how we build and use them today. Whether you’re a beginner with a small shed-style unit or someone planning a full-sized glasshouse, the guides here cut through the noise. No fluff. Just what works in real UK gardens.