Where is the best place to put a greenhouse?

A greenhouse is more or less permanent, and moving one is a day's work with two people. Winter light is the scarcest resource in a British greenhouse, so every siting decision is really about maximising light between October and March — then about not making the thing unusable in a gale, and not putting it so far from the house that you stop visiting it in February.

Step by step

1. Choose the ridge orientation for winter light.Running the ridge east to west presents the long roof slope to the low southern sun and gives the best light from autumn to spring. A north-south ridge gives more even light in high summer, which is when light is abundant anyway. East-west is the right British default.
2. Get it out of shade, especially winter shade.Shadows are far longer in winter. Check the position at midday in December, not in June. A house, a fence, a hedge or a neighbour's conifer casts a shadow two or three times its own height when the sun is low.
3. Keep well clear of trees.Trees shade, drop leaves and sap that block light and stain the glass, drop branches onto it in wind, and send roots into the border. Site outside the eventual canopy spread, not the current one.
4. Avoid the frost pocket.Cold air is dense and flows downhill until something stops it. The lowest corner of a sloping garden, or the uphill side of a solid fence or wall, collects cold air and is measurably colder on a still night.
5. Deal with wind properly.Wind is what destroys greenhouses. Site with some shelter from the prevailing south-westerly, but use a hedge or a permeable screen rather than a solid fence — a solid barrier creates turbulence on its lee side that is worse than the open wind.
6. Keep the run from the house short.Every metre of distance is a metre of cable and pipe if you ever want power or water, and a metre you will not walk on a wet January evening. A greenhouse near the house gets used; one at the bottom of the garden gets visited in June.
7. Plan the path and the standing area.A hard, usable path that works in winter, and a level area beside the door for pots, bags of compost and a water butt. The door needs room to open fully without hitting anything.
8. Get the base level and square before anything else.A greenhouse frame is not self-supporting and will not tolerate being out of true. Panes crack, doors jam and the whole frame racks in wind. The base has to be level and square, not just flat.
9. Check whether you need permission.A domestic greenhouse is usually permitted development, but the limits are set separately in England, Wales, Scotland and Northern Ireland, and there are conditions on size, height, distance to a boundary and proportion of the garden covered, and different rules for listed buildings, conservation areas and flats. Check before you order.

Tips

• A lean-to against a south-facing house wall is the warmest greenhouse there is. The wall stores heat, the run for power and water is short, and it is far cheaper to keep frost-free.
• Put a water butt on the greenhouse gutter from the start. Rainwater is better than tap water for most greenhouse crops, particularly ericaceous ones, and the gutter run is the easiest supply there is.
• If the only available spot is genuinely poor for light, consider a polytunnel instead — the low sidewalls matter less when the whole structure is translucent.

Common mistakes

• Siting it out of the way, at the bottom of the garden — That is usually the frost pocket, the furthest from services, and the position that guarantees you stop going there in winter — which is exactly when a greenhouse needs daily attention.
• Putting it in the lee of a close-boarded fence for shelter — Solid barriers create turbulence and eddies downwind. A hedge or a slatted screen that lets some wind through gives genuine shelter over a much greater distance.
• Choosing the position in summer — Everything looks light in June. Walk the garden at midday in midwinter with a compass before committing.

Questions people ask