You’ve probably heard this one before:
“Orient your greenhouse directly to the south.”
But what if I told you the perfect orientation isn’t exactly south at all?
Heresy, you say? Stick with me—I’ll break it down for you.
When it comes to greenhouses, sun exposure is king. Think of a greenhouse as a giant solar collector—it needs all the sunlight it can get to function properly.
So yes, a south-facing site with minimal obstructions (trees, buildings, hills) is ideal—but here’s the kicker:
Your greenhouse doesn’t have to face due south to thrive.
You’ll still get plenty of solar energy within 45° of south (or north if you’re in the Southern Hemisphere). See here:
If your greenhouse faces south-southeast or south-southwest, you’re still at 70% solar gain—which is more than enough to grow whatever you need!
The bottom line: You have options when choosing the best site for your greenhouse. Not everyone has the luxury or a perfect south aspect or exposure, so this is good to know.
But let’s dive deeper into why you don’t actually need a perfect south-facing site for your greenhouse:
If we want to get really specific, the ideal orientation isn’t due south—it’s slightly to the east (15° southeast). Why?
Because you want to capture the early morning sunlight for heat when temperatures are at their coldest. And by afternoon, the greenhouse has already accumulated warmth, so receiving slightly less sun is beneficial.
See, I told you it’s not what you think!
Okay, now that you know you’ve got some flexibility, how do you find the best location for your greenhouse?
Oh, I’m glad you asked. I have a simple way to find out this using your smartphone. All you need is the Sunseeker or Sun Surveyor app.
Here’s how I do it when I’m accessing potential sites on my land:
Step 1: Stand on your potential greenhouse site
Open the app and check the map view—this shows how the sun moves across the sky throughout the day.
Step 2: Use the solar compass to find south
Switch to the solar compass mode and face directly south. This will give you a clear idea of where the sun will be hitting your greenhouse.
Step 3: Switch to 3D view & look at the sky
Now, point your phone upwards. This lets you visualize the sun’s path throughout the year, including winter and summer solstices.
Step 4: Check the solar exposure
Follow the sun’s movement from east to west. Look for anything that could block sunlight—trees, hills, buildings.
Using this method, you can compare different sites on your property and pick the one with the best solar exposure. This will generally be the one that offers the least shading from trees, buildings, and other obstructions, has an SW-S-SE aspect, or at least allows you to orient your greenhouse SW-S-SE.
When I did this for my greenhouse site, I found it faced slightly southwest—not perfect, but good enough. Some trees blocked the late afternoon sun, but it wasn’t a deal-breaker since mornings were clear.
So there you have it! You don’t need a textbook-perfect south-facing greenhouse. With some assessment, you can make the best use of what you have.
I hope this gave you some ideas about where to place your greenhouse. Now, go out there and find the perfect spot!
Talk soon,
-William
