Collection: Greenhouses 15-20 m²

Greenhouses Between 15 and 20 m2

A greenhouse between fifteen and twenty square metres gives room for deep permanent beds along both sides and a working path wide enough for a barrow. Trained fruit, grapevines and tall crops all fit under the ridge, and there is space left to work without moving things out of the way first.

This is the point at which most growers stop thinking in terms of a growing season and start thinking in terms of a growing year. The volume of air is large enough to hold conditions steady overnight, and the layout is large enough to keep several crops running at once.

Planning the Layout

Beds on both sides with a central path is the usual arrangement at this size. The path needs to take a barrow, which in practice means around seventy centimetres clear. Anything narrower and you will end up carrying rather than wheeling, which changes how the house gets used.

• Deep beds hold moisture and temperature far better than containers.
• A bench at one end keeps potting and sowing off the beds.
• Vertical training up strings uses the height that this size makes available.

Our potting tables and benches suit a dedicated working corner, which keeps compost and tools away from the growing area.

Using the Height

Fifteen to twenty square metres usually comes with enough headroom for trained fruit and vines, and that vertical space is the part most often wasted. Grapes, cordon tomatoes and cucumbers all crop better trained upward than allowed to sprawl, and training them frees the floor beneath for lower crops.

Height also increases wind load, so the base and anchoring need to be specified accordingly rather than treated as an afterthought.

Managing the Climate

A house this size needs several vents rather than one or two, positioned so air enters low and leaves high. That pattern moves air through the house rather than simply letting the top layer escape, which is what actually cools the space around the plants.

Shading is worth planning for as well. A large glazed area in July can push internal temperatures far past what most crops tolerate, and our shade nets, blinds and shade paint each cut light by a different amount. A maximum and minimum thermometer will tell you which you need before you buy.

Running Costs and Upkeep

Heating a house of this volume through winter is a genuine cost, and it is better estimated before purchase than discovered afterwards. Many owners heat only a partitioned section, or line the glazing with bubble sheet from November to March.

Maintenance is straightforward but regular. Clear the guttering, check the glazing clips after storms, and clean the glass between seasons so the light reaching the plants does not drop away unnoticed.