Placement is free at the planning stage and expensive afterward. Moving a greenhouse means dismantling it, rebuilding the base and reassembling, which is most of the labor of a new build. 🧭 So this is worth getting right on paper.
The short version: maximum winter sun, ridge running east to west if you can, out of the wind funnel, and away from anywhere water collects. Everything below is how to check each of those in your own yard, with a tape measure and an afternoon. ☀️
☀️ Sun: the one that is not negotiable
You want at least six hours of direct sun in the growing season. That much is well known. The part people get wrong is which season to measure. 🔍
Winter sun is the sun that counts
The sun sits far lower from November to February, so shadows are dramatically longer. A spot in full sun in June can be in complete shade all winter behind the same house, fence or conifer. 🌲
If your reason for buying is season extension, early sowing or overwintering, winter light is the whole point of the purchase and the June test tells you nothing useful.
How to actually check it
- 📷 Photograph the candidate spot at 9 a.m., noon and 4 p.m. on the same day, and note where shadows fall.
- 📏 As a rough winter rule of thumb, expect a shadow roughly two to three times the height of the object casting it at midwinter midday in most of the continental US. A 20 ft tree can therefore shade 40 to 60 ft to its north.
- 🧭 Face south and look for anything tall in that arc: the house, garages, fences, evergreens, a neighbor's roofline.
- 📱 A sun-path or shadow app will model the winter angles for your latitude in a couple of minutes and is worth the download.
⚠️ The distinction worth making: deciduous trees are usually acceptable, evergreens usually are not. A maple drops its leaves exactly when you need the light and shades you exactly when you want shade. A conifer does neither.
🧭 Orientation: which way should the ridge run?
There is a genuine answer here, and it depends on what you are doing.
Ridge running east to west
This puts one long side facing south. It maximizes light capture in winter, when the sun is low and comes from the south, and it is the orientation to choose if season extension and winter growing are the point. ❄️
The trade-off: in high summer, one long side gets much more sun than the other, so plants receive less even light across the structure.
Ridge running north to south
Both long sides get sun as the day moves, giving more even light in the main growing season. This is the better choice if you mostly use the greenhouse from March to October and even growth across benches matters more than midwinter light. ☀️
What we would actually tell you
Orientation is a real effect but a second-order one. A north-south greenhouse in full sun beats an east-west greenhouse in partial shade, every time. Pick the sunniest spot first, then orient within whatever freedom that leaves you. 🎯
And if the greenhouse is primarily a place to sit rather than to grow, orientation becomes an amenity question instead: where do you want the morning light, and where does the evening sun land on the seating.
💨 Wind: the load that destroys greenhouses
More backyard greenhouses are lost to wind than to any other cause. Site selection is your first line of defense, before ratings and before anchoring. 🌬️
What to avoid:
- 🏗️ Gaps between buildings. A passage between a house and a garage accelerates wind considerably. This is the classic mistake, because the spot looks sheltered.
- 🏔️ Exposed ridges and the tops of slopes, where there is nothing upwind at all.
- 🧱 The lee side of a solid fence or wall. Solid barriers create turbulence and downdrafts behind them rather than shelter.
- 🌳 Directly under large trees, which is a falling-limb problem more than a wind problem, and also a sap, leaf and shade problem.
What helps: a permeable windbreak upwind, a hedge or a slatted fence, which slows air rather than deflecting it. As a rule of thumb, a permeable barrier gives useful shelter for a distance of roughly eight to ten times its height downwind. 🌿
💡 Find your prevailing wind direction before choosing: your local airport's wind rose, or simply which side of your fences and trees carries the weathering. On a genuinely exposed lot, the structure matters as much as the siting, so read the published wind rating before you shortlist.
💧 Drainage: the slow failure
Wind is the fast way to lose a greenhouse. Water is the slow one. 🌧️
Three checks, all free:
- 1️⃣ Look the day after heavy rain. Standing water anywhere on the footprint disqualifies the spot until it is fixed.
- 2️⃣ Dig a percolation hole a foot deep, fill it, and time the drainage. Several hours means heavy clay and a base that needs more depth.
- 3️⃣ Follow the ground fall. Where does surface water travel across your yard, and does the candidate spot sit in that path or downhill of a large hard surface?
Also consider where the greenhouse's own roof water will go. A structure with real roof area sheds a surprising volume, and if it discharges onto the base you just built you will be dealing with it every winter. Gutters into a rain barrel solve it and are worth planning at siting stage. 🚰
Avoid frost pockets too: cold air flows downhill and pools at the bottom of a slope or against a solid barrier across it. A greenhouse sited in one gets measurably colder nights than the same greenhouse twenty feet upslope. ❄️
🚶 Access, and the things you only notice later
The purely practical constraints that decide whether the greenhouse gets used: 🧰
- 🪴 A path you can use in the dark and in the rain, wide enough for a wheelbarrow. If reaching it means crossing wet lawn in slippers, you will visit it less.
- 💧 Distance to a water source. Every extra step is repeated daily in July.
- ⚡ Distance to power, if you ever want it. Trenching cable is far cheaper at the same time as the base than later.
- 🚛 Route from the curb. The pallet is delivered curbside. Measure the gate, the tightest corner and the steps now, not on delivery day.
- 👁️ The view from the house. You will look at it far more than you stand in it. This is not a trivial criterion, especially for glass models.
📏 Clearances and rules that constrain the spot
- 📍 Setbacks from property lines, commonly three to ten feet, and entirely local. They apply whether or not a permit is needed, as we set out in our permits guide.
- 🏡 HOA siting rules, which frequently require the rear yard or a position not visible from the street.
- ⚡ Easements, which cannot be built over regardless of zoning. Your plat map shows them.
- 🪵 Working room: leave at least two feet clear all around, three is better, for assembly, cleaning and future maintenance.
- 🌳 Distance from trees: aim for at least the mature canopy radius, for roots, limbs, leaf fall and shade.
🏛️ Siting a garden room is a different exercise
If the structure is somewhere to sit rather than somewhere to grow, the priorities reshuffle and light stops being the top criterion. 🪑
- 🌅 Time of day matters more than total hours. Evening sun on the seating side is usually worth more than midday intensity.
- 🌲 Some afternoon shade is an asset rather than a problem. A glass structure in unbroken south-facing sun is a beautiful room that is unusable in July without shading.
- 👁️ The view out becomes a primary criterion, and so does the view of it from the house.
- 🚶 Proximity to the house matters enormously, because a room at the far end of the yard gets used in fine weather only.
This is the reason a lean-to model exists: The Retreat sits against an existing wall, which puts it a step from the door, borrows warmth from the building and removes one wall's worth of heat loss. Note that attaching to the house often changes the permitting picture, so check that before committing. 🏠
🪵 The staking exercise, which is worth more than all of the above
- 1️⃣ Stake and string the exact footprint of the model, checking the diagonals are equal.
- 2️⃣ Mark where the door will be and make sure it opens onto something sensible.
- 3️⃣ Leave it for a week. Walk past it daily. Look at it from the kitchen, from the patio and from the neighbors' likely angle.
- 4️⃣ Watch where the shadow falls across a full day, and imagine it two or three times longer in January.
- 5️⃣ Then move it three feet and see whether it improves. It often does.
⏳ There is time to do this properly: made-to-order structures take roughly four to six weeks for polycarbonate, ten to twelve for the wood-framed range and fourteen to sixteen for glass. Stake the site the week you order and you will have finished the base before the pallet arrives.
❓ FAQ: where to put a greenhouse
How much sun does a greenhouse need?
At least six hours of direct sun during the growing season, and as much winter sun as you can get if season extension is the goal. Winter shadows are two to three times longer than summer ones, so measure for the harder case. ☀️
Should a greenhouse face south?
A long side facing south, meaning the ridge running east to west, maximizes winter light. North to south gives more even light in the main season. Both are second-order compared with simply choosing the sunniest available spot. 🧭
Can I put a greenhouse against a fence or wall?
Against a wall, yes, and a lean-to is designed for exactly that. Against a fence, leave working room, at least two feet, and check your setback rules, since fences usually sit on the boundary. 🧱
How far from trees should a greenhouse be?
At least the radius of the mature canopy. Closer than that brings shade, sap, leaf fall, root disturbance and the risk of falling limbs, and evergreens are worse than deciduous trees on every count. 🌳
Is a windy site a dealbreaker?
No, but it raises the requirements. Choose a structure with a published wind rating, anchor it exactly to specification, and plant or build a permeable windbreak upwind rather than a solid one. 💨
What if the only sunny spot is at the back of the yard?
Take the sun and solve the access. A firm path, a water source and lighting turn a distant greenhouse into a used one, and all three are cheaper than a shaded greenhouse close to the house. 🪴
🌿 How we would decide
Sunniest spot first, especially in winter. Then out of the wind funnel. Then off the wet ground. Then orientation, then access, then the view. In that order, because the first three cannot be fixed later and the last three can. 🧭
Stake it before you order, and check the footprint against the exact dimensions of the model you want. Every structure in the Prime Greenhouses range publishes footprint, ridge height and wind rating on the page, so you can test a specific building against a specific site rather than guessing at both. 📊
And once the site is fixed, the base follows from it: we compared the options in our foundation guide. 🧱