Collection: Grande serre

What Counts as a Large Greenhouse

A large greenhouse of ten square metres or more gives room for permanent beds, staging down both sides and a clear central path. The practical change from a smaller frame is that you can walk around inside and work without moving things out of the way first, and that alters how often the house gets used.

It also holds conditions more steadily. A larger volume of air is slower to lose heat overnight and slower to spike on a sunny morning, which makes the internal climate easier to manage than in a small frame.

Planning the Layout Before Assembly

At this size the interior needs designing rather than filling. Two arrangements cover most cases: staging one side with a bed opposite, or beds on both sides with a path between.

• Staging suits propagation, seed raising and container growing at working height.
• Permanent beds hold soil temperature and moisture far better than containers.
• The path needs around seventy centimetres to be workable with a barrow.

Retrofitting staging or building raised beds around an established layout is harder than setting it out from the start.

Using the Height

Larger houses usually come with more headroom, and that vertical space is what most often goes unused. Vine tomatoes, cucumbers and trained fruit all crop better grown upward on strings than allowed to sprawl, and training them frees the floor beneath.

Height also increases wind load, so base preparation and anchoring need specifying accordingly rather than treated as a formality.

Climate at This Scale

Ventilation needs to scale with the house. As a rough guide, total vent area should be around a fifth of the floor area, which usually means several roof vents plus louvres at low level to draw cool air in.

Heating costs scale with cubic volume, not floor area, and this is where owners are most often caught out. Insulating with bubble sheet from the protection range or partitioning and heating one end are both more effective than buying a larger unit.

Groundworks

The base carries the frame and keeps it square, and at this size that usually means a concrete perimeter or slab rather than a proprietary base frame. It must be level, drained and square before the frame arrives.

Access matters too. A house of this size arrives on a pallet and needs a route to the site. If you are weighing sizes, the size guide sets out what each band actually allows.