Where to Put a Greenhouse: Site Selection for Sun, Wind, and Drainage
South-facing isn't the whole rule. The real site-selection checklist for sun, ridge orientation, trees, drainage, and utility access, before you order.
Installation
Quick answer: South or southeast is the right general answer, but it is not the whole rule. Purdue Extension's own construction guidance (January 2026) splits it by latitude: above about 40°N, orient a single-span greenhouse with its ridge running east-west, long side facing south, for the most winter light; below 40°N, run the ridge north-south instead, because the sun sits higher and even light distribution matters more than raw transmission. In a hot-summer climate, the side to actively avoid is west, where the afternoon sun is the problem, not the fix, per University of Arizona Cooperative Extension. Beyond sun, the site needs to be level and well-drained, clear of a low frost pocket, within reach of water and power, and clear of a tree's falling-limb zone even if you want its summer shade. Get the spot wrong and you pay for it in heating cost, overheating risk, and a base that never sits right, before the first pane goes in.
Best for
Buyers who already know which greenhouse they want, or are close to it, and are now walking their own yard trying to decide where it actually goes.
Wrong fit
Buyers still deciding between glass and polycarbonate, or what size to buy. Settle those first, then come back to site selection; the kit decides the footprint this guide works around.
Tradeoff
The sunniest spot in a cold climate is often the hottest, most exposed spot in a hot one. The right site depends on your climate and your goal (growing through winter versus avoiding a July cook-off) at least as much as on a universal rule.
Every greenhouse guide says "put it somewhere sunny, facing south." That's true as far as it goes, and it is also not enough to actually decide where the thing goes in your yard. South-facing advice written for a cold Vermont winter and south-facing advice written for a Phoenix summer should not be the same sentence, and most of what ranks for this question treats them as if they are.
We don't sell greenhouses. We save you from buying the wrong one, and picking the wrong spot in the yard is one of the quietest ways to do that: a greenhouse sited in the shade of a maple runs cold and underlit all winter, one sited against a west-facing fence cooks every plant in it by 2 p.m. in July, and one sited in the low corner of the yard sits in standing water and frost every single year. None of that shows up on the kit's spec sheet. This guide is the site-selection checklist that actually accounts for where you live, not a single universal rule.
Quick Answer: Rank Your Candidate Spots
Side of house or yard
General rank
Why
South or southeast
Best
Captures the most sun from fall through winter; the long side of the greenhouse should face this direction
East
Second best
Strong morning sun, cooler afternoons; a good hot-climate compromise
Southwest or west
Third, avoid in hot climates
Afternoon sun is the most intense light of the day; fine in a cold climate that wants the extra heat, a liability in a hot one
North
Last resort
The least sun of any orientation; workable only for shade-tolerant propagation, not general growing
Sources: University of Georgia Extension Bulletin B-910 (national ranking) and University of Arizona Cooperative Extension Backyard Gardener #6 (the explicit hot-climate call to avoid west), both checked October 10, 2026.
Orientation Isn't Just "Face South," It Changes by Latitude
Almost every vendor blog on this topic gives one rule: face the long side south. Purdue Extension's own January 2026 greenhouse construction guidance is more specific, and it actually changes depending on where you live.
Above roughly 40°N latitude (most of the Northeast, the Upper Midwest, the Mountain West, and the Pacific Northwest, the core of this site's own buyer base), the sun's winter path is low and southerly. For a single, freestanding greenhouse, Purdue recommends building it so the ridge runs east-west, meaning the long side of the structure faces south. That orientation maximizes how much of that low winter light actually gets transmitted into the house, instead of reflecting off a shallow-angle roof.
Below roughly 40°N latitude, the sun sits higher in the sky even in winter, so light transmission is less of a problem and even distribution matters more. Purdue's guidance flips there: orient the ridge north-south instead, which shortens the shadows structural members cast inside the greenhouse and spreads light more evenly across the growing space.
A rough gut-check: 40°N runs close to Denver, Columbus, and Philadelphia. If you are north of that line, which covers most of this site's cold-climate buyer base, the east-west ridge and south-facing long wall is the one to build toward. If you are south of it, north-south is the better call.
This is a general physics-of-light rule, not a product spec. It holds regardless of which brand you buy, but it changes nothing about a kit's wind or snow rating, covered separately in greenhouse wind anchoring and greenhouse snow load.
Your Climate Changes the Goal, Not Just the Direction
The same "face south" instinct assumes the problem is getting enough sun. For a lot of this site's buyers, cold-climate growers trying to stretch the season or keep plants alive through winter, that is exactly the problem, and the orientation and site-ranking table above solves for it directly. Pair it with best greenhouses for cold climates and overwintering plants in a greenhouse if that is your goal.
But University of Arizona Cooperative Extension's backyard-scale guidance for Yavapai County names a different failure mode directly: in a hot climate, too much sun is the problem, and the side to actively avoid is west, where the afternoon sun is at its most intense. The same extension office is blunt that most of Arizona is "too hot to rely on air vents and shade cloth" alone for summer growing, which is a ventilation and shading problem as much as a siting one. If overheating, not cold, is your real risk, read this alongside ventilation and overheating and the shade cloth guide before you commit to a spot.
Trees: A Real Tradeoff, Not a Blanket "Avoid Shade" Rule
Most SERP advice on this topic says only "avoid shade from trees," which skips the actual tradeoff. University of Georgia Extension's hobby-greenhouse bulletin is more useful here: a deciduous tree can be a genuine asset, shading the greenhouse from intense late-afternoon summer sun while dropping its leaves in time to let full winter light back in. The same bulletin names the real cost of that choice directly: falling limbs can damage the structure, a risk that does not apply to an open, treeless site.
There is no backyard-scale rule in any primary source we checked for exactly how many feet to keep from a tree. Purdue's own construction guidance gives a 100-foot tree-line clearance figure for snowdrift and shadow control, but that number comes from commercial, multi-acre greenhouse operations and does not translate directly to a typical residential lot; we are naming it here only to explain the mechanism (a tree line can shadow a structure and build snowdrift against it), not as a distance you need to hit in your own yard. The practical version: judge each tree by the shadow and snow-load it actually casts at the time of year you plan to grow, and by whether a dead or overhanging limb could reach the structure, not by a borrowed commercial-scale number.
Wind: Covered in Full Elsewhere, Summarized Here
Siting for wind gets its own full treatment, with anchoring, failure modes, and standard references, in greenhouse wind anchoring. The short version repeated here because it belongs in the same site-selection pass: avoid the top of an exposed slope and the funnel between two buildings, where wind speeds up, and use a hedge, fence, or building to windward as a windbreak, with enough clearance that it doesn't create turbulence right at the greenhouse instead of blocking the wind. A commercial-scale design minimum cited by Purdue Extension, roughly 5 psf dead load, 5 to 15 psf live or snow load, and a wind design baseline around 10 psf (about 80 mph), gives a sense of the physics at play, but it is a generic commercial design floor, not a number tied to any backyard kit you can buy; check the specific wind and snow figures a manufacturer actually publishes for its model in greenhouse snow load instead.
Drainage and Frost Pockets: The Low Spot That Looks Fine in Summer
A level, well-drained site is standard advice everywhere, and it's correct, but "well-drained" misses half the problem in a low corner of the yard. Cold air is denser than warm air and drains downhill at night the same way water does, settling into low-lying or bowl-shaped ("concave") ground and sitting there. Michigan State University Extension's frost-monitoring guidance describes this cold air drainage directly: concave terrain is measurably colder and frostier than higher, convex ground nearby, and during a still, clear-sky temperature inversion, the air right at ground level can run several degrees Fahrenheit colder than the air just five or six feet above it.
For a greenhouse, that means the lowest-looking, flattest corner of the yard, the one that seems like the easiest build site, can also be the coldest and last to warm up in spring, on top of being the wettest. Walk your candidate site after a hard rain and again on a clear, calm, cold morning before you commit. A spot that is merely damp after rain is a drainage problem the base can solve, covered in the foundation and base guide; a spot that is reliably the frostiest corner of the yard on calm mornings is a siting problem no base fixes.
Access, Water, and Power
The least glamorous site-selection factor is also one of the most expensive to get wrong after the fact. University of Georgia Extension's guidance notes a real upside to siting a greenhouse near a door, window, or basement entrance of the house: you can draw on the house's own heat and you get easier daily access for watering and harvest. Before you pick a spot, walk the realistic path from your water spigot and your electrical panel to the candidate site and price what a trench or a new run would cost, the same unglamorous line item covered in the real cost of a greenhouse and in greenhouse heating cost if you'll be running power for a heater or automatic vents.
Mountain West Example: Front Range Siting
Colorado State University Extension's own hobby-greenhouse guidance for the Front Range gives a concrete regional version of all of the above: orient for at least 3 hours of direct winter sun, typically a southeast exposure, plan a windbreak against the prevailing northerly and westerly winds that hit the Front Range, and set footers below the local frost line, roughly 3 feet deep in that region. Treat this as one named regional example, not a national rule. Confirm your own area's frost-line depth and prevailing wind direction with your local extension office or building department before you dig.
Site Selection Checklist
Check
Pass
Red flag
Sun orientation
Long side faces south (above ~40°N) or ridge runs north-south (below ~40°N); 6+ hours of direct sun for general growing
Mostly shaded by a structure or evergreen tree that never drops its coverage
Climate fit
Cold climate: maximize sun. Hot climate: avoid west-facing afternoon sun
West-facing site in a hot-summer region with no shade or ventilation plan
Trees
Deciduous tree gives useful summer shade and clears by winter; no dead or overhanging limbs within striking distance
Evergreen blocking winter sun, or any limb that could fall on the structure
Wind
Some shelter from a windbreak, not in the funnel between buildings or the top of an exposed slope
Directly atop an exposed ridge or in a gap between two buildings
Ground
Level, firm, well-drained; not the lowest or coldest corner on a calm morning
Standing water after rain, or visibly frostier than the rest of the yard
Utilities
Water and power reachable without a long, expensive trench run
Spigot or panel far enough away that running a line changes the budget materially
Legal
Clear of setbacks, easements, and HOA placement rules
Inside a setback or easement; no HOA check done yet
Setbacks and HOA rules are their own gate, covered in full in do I need a permit for a greenhouse. A site can pass every check above and still be illegal to build on; check that guide before you order.
What We Could Not Verify
No primary source gives a specific backyard-scale distance to keep from a deciduous or evergreen tree. Purdue's 100-foot figure is commercial-acreage scale and is cited here only to explain the snowdrift and shadow mechanism, not as a number to apply to a residential lot.
No primary source gives a precise temperature difference for a frost pocket under a backyard greenhouse specifically. MSU Extension's inversion figure describes the general cold air drainage principle (a few degrees Fahrenheit over several feet of height), not a backyard-greenhouse-specific delta.
The claim that the mathematically ideal orientation is a fixed number of degrees east of true south (a figure repeated on a few non-extension blogs) was not found in any extension or engineering source checked this run, and is not repeated here as fact.
No AI-answer panel was run for this topic this run; it falls outside the frozen stable-prompt set in .seo/citation-log.md and the ten measured questions in .seo/zerorank-coverage.md.
Frequently Asked Questions
Does a greenhouse have to face south?
Mostly yes, with a latitude-based twist. Above about 40°N, Purdue Extension's own guidance recommends the long side facing south with the ridge running east-west, for the most winter light. Below 40°N, the better orientation flips to a north-south ridge, since the sun sits higher and shadow length matters more than raw transmission. Neither is a hard rule if your yard genuinely does not allow it; east is a solid second choice almost anywhere.
Can I put a greenhouse near a tree?
Yes, and it can even help. University of Georgia Extension notes that a deciduous tree can shade a greenhouse from the hottest late-afternoon summer sun while dropping its leaves in time to let winter light through. Weigh that against the real risk the same source names: a falling limb can damage the structure, so check for dead wood and overhanging branches before you commit to the spot.
What if the only good site in my yard is sloped or sits lower than the rest?
Sloped or low ground is not disqualifying, but it changes your base cost and your frost risk. A sloped site usually means a leveled cut or a stronger base, covered in the foundation and base guide. A low, bowl-shaped corner is worth a second look regardless of slope: cold air drains downhill at night and pools there, per Michigan State University Extension, so the lowest corner of the yard is often also the coldest and last to warm in spring.
Does a greenhouse need to be close to the house?
Not necessarily, but there's a real upside if it is. University of Georgia Extension notes that siting near a door, window, or basement entrance lets you use heat from the house and makes daily access easier. Weigh that against the realistic cost of running water and power to a farther spot, covered in the real cost of a greenhouse.
My yard only has a north-facing or mostly shaded spot. Is that a dealbreaker?
It's the least favorable orientation in every ranking we found, University of Georgia Extension puts it last behind south, east, and west, but it isn't automatically disqualifying if your goal is shade-tolerant propagation rather than general year-round growing. For most buyers wanting to grow vegetables or overwinter tender plants, it's worth seriously comparing against a smaller greenhouse in a better-lit spot before you commit to the shady option. See what size greenhouse do I need for how the size and orientation decisions interact.
These guides are built from manufacturer documentation, public specifications, primary research where health claims matter, and repeated buyer questions that show up in real ownership and installation decisions.
Manufacturer responses can clarify pricing bands, warranty terms, support footprint, or common mistakes. They do not move a page up the shortlist on their own.
