What is an orangery?
An orangery is a heatable building in which container plants — originally citrus and orange trees above all — are overwintered frost-free. It is recognisable by a solid rear wall and a front elevation made almost entirely of tall windows, usually facing south.
Orangeries appeared in Europe from the sixteenth century and reached their peak in the seventeenth and eighteenth centuries at palaces, country estates and botanical gardens. Citrus trees were status symbols at the time and could only survive a northern European winter in a sheltered, heated space.
How an orangery differs from a greenhouse
The distinction lies in the ratio of glass to masonry:
| Orangery | Greenhouse | |
|---|---|---|
| Roof | Mostly solid (tiles, lead, zinc) | Largely glass |
| Rear wall | Solid masonry | Glass or lightweight panel |
| Purpose | Overwintering, keeping frost-free | Growing and cultivation, growth light |
| Thermal mass | High — the walls buffer heat | Low |
The solid roof is functional: in winter the plants need warmth more than light, and a massive rear wall stores solar heat during the day and releases it at night.
Features and building considerations
- South orientation. The window wall catches the low winter sun; the closed north side limits heat loss.
- Tall, narrow windows with glazing bars, often running from floor to cornice so that tall container trees fit through.
- Frost-free, not warm. Around 5 to 10 degrees Celsius is enough for citrus. Warmer means more transpiration while light is scarce, which weakens the plant.
- Ventilation. Without air movement you get mould and leaf drop. Provide opening lights or vents high and low.
- Floor. Load-bearing and water-resistant; large container trees quickly weigh several hundred kilograms each.
- Condensation. With single glazing, condensation runs inward. In new build, insulating glazing and a drainage channel below the windows are sensible.
Modern orangeries are often built as garden rooms: the same architectural language, but with insulating glass and a heat source so they are usable all year.
Related terms
- Glazing
- Facade
- Cornice
- Conservatory
- Listed building
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