If you’ve decided to build a greenhouse, you have one major decision to make: Do you build a lean-to greenhouse or a freestanding greenhouse?
I own a lean-to greenhouse that is attached to the west side of my house. It replaced an older, dilapidated one the previous house owner built out of scrap construction materials.
So in one way simply replacing the existing greenhouse with a better, slightly larger greenhouse made sense. I already had the space set aside.
However as I continued to improve the greenhouse and add more features, I realized that there were other benefits to having a lean-to greenhouse attached to my house.
And there are also some downsides.
Having to wash your hands or tools in cooler weather with ice cold water from the tap is not pleasant.
So one of the best upgrades I made to my greenhouse was to add hot and cold running water.
And it was easy! I luckily have my laundry room on the other side of the wall so I just hired a plumber to tap into the hot and cold lines that went to my clothes washer, drill two holes through the wall and plumb up the laundry sink I had already installed.
Together with a repurposed old kitchen tap, I now have running hot and cold water, even in winter.
Had I wanted to do this with a freestanding greenhouse I would have had to have a water line run out to the greenhouse, found a way to heat the water (likely with a small under sink on-demand heater) and in freezing weather, turn the water off and drain the water line.
Easy Electrical Access
Electricity is also handy to have in the greenhouse for running heating mats when seed starting, grow lights and even a shop vacuum cleaner to clean up debris (especially spider webs!)
But again with a freestanding greenhouse, you would have to have a cable run underground to the greenhouse in accordance with local electrical standards.
In my case, since I have power from my house in my garden shed that is under my second floor deck, I simply strung up an extension cord to where I need power in my greenhouse.
Eventually I plan to put in a dedicated electrical line with outdoor outlets space along the bench where I need power the most.
Less Building Materials
A free-standing greenhouse requires you to build four walls. In my case I only really had to build two walls, as the west wall is shared with my house and the north wall is shared with the aforementioned garden shed.
So I needed less cedar framing, less windows and less roof covering (in my case twin-wall polycarbonate).
The west wall of my house also is painted white and reflects the light well in wintertime when we have less sun.
Windows Into My Greenhouse
Another benefit of my lean-to greenhouse is that I happen to have two windows in my house that are in the wall that is shared with the greenhouse. So I can look out of the windows into the greenhouse to check up on things without going outside.
I often look through my laundry room window to see if I remembered to close the greenhouse door (especially in summertime when I ventilate it during the day).
But so far I haven’t tried to climb through the window to go into the greenhouse. Maybe my daughter would fit better than me.
Some lean-to greenhouses are situated so that a house door that before lead outside, then leads into the greenhouse once that is built.
A Wide Open Backyard
A lean-to greenhouse is tucked nicely out of the way next to your house, so that leaves most of your backyard open and available for other uses.
In my case I have my 245 square feet of raised vegetable beds, nine fruit trees, raspberry patch, flower beds and an in-ground pond.
But when it comes to location all is not rosy with having a lean-to greenhouse instead of a freestanding greenhouse.
Location and Sun Exposure
With a freestanding greenhouse, you’re not tied to a particular location. Yes, you do have to work around whatever exists in your backyard such as trees and structures.
However with a lean-to greenhouse you are likely stuck with just a few locations around your house. You definitely don’t want to build your lean-to greenhouse on the north side (if in the Northern Hemisphere like I am) as the greenhouse will get little sun exposure.
You’ll also have other obstacles to work around such as decks attached to your house, gas and electric meters, etc.
So in my case I ended up putting my greenhouse back into the same location the old one was in, which is on the west side of my house. Really the only location I could use, as the east side is my driveway and a pond and the south side is where my raspberry patch is.
If you do have the choice, the south side is the best side of your house to put a lean-to greenhouse. However keep in mind that if you have a neighbouring house, that will block the sun as is the case for my south side.
The other issue is that you will have a certain size limitation as to how large you can make your lean-to greenhouse. Length is likely going to be the biggest constraint, as you’ll likely have some kind of obstacle that dictates how long the greenhouse can be.
In my case it’s my deck on one side and on the other side I had a peach tree (until I killed it), my garage back door and another peach tree – all not easily moveable or easy to build around.
Width is also generally constrained as you can only span a certain width with a single rafter. In my case I also had a path in front of my greenhouse I wanted to maintain and while I did extend the greenhouse slightly (which meant making a new foundation wall), I was still limited.
So I do wish I had a bigger greenhouse and for that I maybe should have built a freestanding one instead.
Ventilation is Key
Adequate greenhouse ventilation is always important, whether it’s a free-standing greenhouse or a lean-to greenhouse. However with a lean-to greenhouse there is less opportunity to have air moving through the greenhouse, so care must be taken to have more vents and also some form of active cooling.
In my case I have my solar-powered ventilation fans, which work quite well in keeping the air moving. Having a greenhouse attached to your house means being more vigilant about mold and mildew build-up.
And automatic greenhouse roof vent openers are also a must.
I also try to avoid overwatering plants that I overwinter in the greenhouse, considering that we have very damp, mild winters.
So as you can see there are various benefits but also some downsides to building a lean-to greenhouse over a freestanding greenhouse.
I also did a companion video to this post:
Will I one day build a freestanding greenhouse? Maybe. I have my eyes on a spot, but have to convince my wife to part with some flower beds to make room for it. Plus wait for the price of lumber to go down, if it ever will!
If you have any questions about greenhouses and growing in them, post a comment below.
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Wishing you all the best!
Tranquil Urban Homestead, Victoria, BC