Almost every guide to siting a greenhouse gives the same answer: put it where it gets the most sun. That is right if you are growing, and it is the wrong answer if you are not.
A greenhouse does two quite different jobs, and they pull the position in different directions. One is production: seed raising, tomatoes, cucumbers, overwintering. The other is somewhere to sit with a glass of something as the light goes, warm long after the garden has cooled. Both are legitimate, and plenty of people want a bit of each.
Work out which matters most before you measure anything. It changes the answer.
Siting for Growing
If the greenhouse is mainly a working space, light is the constraint, and winter light in particular. A position that is bright in June may be in shadow from October to March, which is exactly when a greenhouse earns its cost.
Orientation
Run the ridge east to west. That puts one long side facing south, which catches the low winter sun across the greatest glazed area. It is the standard recommendation for a reason.
Running it north to south gives more even light through a summer day and works well if summer cropping is the priority. The difference matters less than people think in June and considerably more in January.
Shade
Check the site across a whole day rather than at the moment you happen to be standing in it. A spot that is sunny at noon can be in shadow by three, and the difference is invisible unless you look for it.
Then check it across the year. Buildings and fences cast much longer shadows in winter, when the sun sits low. A wall that is no problem in July can put the whole footprint in shade in December.
Keep clear of trees
Trees cause three separate problems, and none of them improves with time. Falling branches break glass. Leaf litter and sap cut light transmission and are tedious to clean off. Roots lift bases and block drainage.
Deciduous trees are the trap. Bare in winter and apparently harmless, they shade heavily from May onwards, which is the wrong way round for a greenhouse.
Shelter without shade
Wind cools a greenhouse faster than anything else and puts load on the frame. A hedge or fence to the windward side helps considerably, provided it is far enough away not to cast shade across the glazing.
A permeable barrier such as a hedge works better than a solid one. Wind hitting a solid fence lifts over it and comes down hard on the other side, sometimes worse than no barrier at all.
Siting for Evenings and Enjoyment
If you want somewhere to sit as much as somewhere to grow, the priorities change. This is closer to how an orangery is sited than how a working greenhouse is, and the two decisions genuinely conflict.
Face west, not south
A west facing aspect catches the evening sun and holds warmth into the night, which is the whole point of sitting in a glasshouse in September. South is better for plants; west is better for people.
Glass holds heat for an hour or two after the sun has gone, and on a clear evening that is the difference between sitting outside until nine and going indoors at seven.
Keep it close to the house
A greenhouse at the end of a long garden gets visited when there is a job to do. One a few steps from the back door gets used casually, and that is what turns it into a room rather than a shed.
Proximity also makes power and water practical, and both matter if you want lighting for the evenings and somewhere to put a kettle.
Think about the view both ways
You will look out of it, and you will look at it from the house. A greenhouse sited where it blocks the view from the kitchen window is a daily irritation. One placed as a focal point at the end of a sightline is the opposite.
This is where shape earns its cost. A hexagonal or round frame reads as a garden feature rather than a utility building, which matters when you are looking at it every day.
Leave room to sit
Seating takes floor space that growing would otherwise use. Below about ten square metres you will be choosing between the two rather than fitting both, so if evenings matter, size up. The size guide sets out what each footprint actually allows.
Outside the frame, a paved area beside the door extends the usable space at no cost to the growing area, and a patio canopy over it covers the gap between greenhouse and house in poor weather.
Splitting the Difference
Most people want both, and there are three workable compromises.
- South west aspect. Good winter light, and the evening sun from about four o'clock onwards. The usual answer when you cannot decide.
- Size up and zone. In a house above about twelve square metres, keep growing at one end and seating at the other. A partition lets the two ends be vented and heated differently.
- A lean to against the house. A lean to greenhouse on a west or south west wall gains stored heat from the masonry, sits within a few steps of the door and takes very little garden.
The Practical Checks
Drainage
Avoid the low point of the garden. Water collects there, undermines the base and stands around the frame. If the only available spot is low lying, plan the groundwork accordingly and get the levels right before the frame arrives.
Access
You will carry compost, pots and water to it, and at some point you will carry a pane of glass. A path wide enough for a barrow saves more time over a season than most equipment does, and it needs to be usable in January mud rather than only in June.
Water and power
Rainwater from the guttering into a butt covers most watering. Power is a bigger decision: it opens up electric heating, lighting and fans, and it is far cheaper to run a supply during groundwork than to dig a trench afterwards.
Boundaries and neighbours
Leave enough space to walk around all four sides. You will need it for cleaning, for replacing glazing and for clearing gutters, and a greenhouse hard against a fence is a maintenance problem from day one.
Most domestic greenhouses fall under permitted development in the UK, but conditions apply to height, position relative to boundaries, and listed or conservation status. Check before you build rather than after.
Exposure
Open sites, coastal gardens and hilltops all take more wind than an average garden. That does not rule them out, it means the base and the fixings need specifying for it. An anchor kit matched to your base should be fitted during assembly.
Where Not to Put It
- Under or beside trees. Branches, sap, leaf fall and roots.
- At the low point of the garden. Water collects and stays.
- Tight against a fence or wall. No access for cleaning or repairs.
- In a wind funnel between buildings. Narrow gaps accelerate wind rather than shelter from it.
- Wherever there happens to be room. The most common reason a greenhouse gets used less than expected.
Common Questions
Which way should a greenhouse face?
For growing, run the ridge east to west so one long side faces south. For sitting out on summer evenings, a west or south west aspect holds warmth later into the night.
How much sun does a greenhouse need?
At least six hours of direct sun a day through the growing season, and as much winter light as the site allows. Winter is the limiting factor, not summer.
Can a greenhouse be in partial shade?
Yes, with adjusted expectations. Propagation, hardening off and shade tolerant crops work well. Fruiting crops such as tomatoes and peppers will underperform.
How far from a fence should a greenhouse be?
Far enough to walk around and work, which in practice means around 60 cm minimum on any side you need to reach. Check local boundary rules as well.
Can I use a greenhouse as a garden room?
Yes, and many people do. Site it west facing and close to the house, allow floor space for seating, and plan shading from the start, since a glasshouse used by people needs summer temperatures managed more carefully than one used only by plants.
Next Steps
Once the position is settled, size follows from it. The size guide covers what each floor area allows, and the full greenhouse range can be filtered by size, shape and material.
If the space you have is awkward rather than open, a corner, narrow or lean to frame will often fit where a standard rectangle will not.
