10 Of The Most Commonly Asked Questions About Our Zone 3 Backyard Greenhouse
I’ve written a handful of posts about our zone 3 backyard greenhouse over the years (all linked below) but still continue to get asked the same questions about it. So I figured, rather than having your parse through greenhouse content to find what you’re looking for, I’d put it all in one blog. So here’s 10 of the most commonly asked questions about our zone 3 backyard greenhouse. With my detailed answers! You’ll find info on how we built our DIY greenhouse, what we grow in it, what we grow in a Zone 3 greenhouse in the Winter and much more. Hope you enjoy and find it helpful!
This post covers (click any link to be brought to that section):
- Is your greenhouse a kit or did you build it?
- How much did it cost to build your greenhouse?
- What size is your greenhouse? And is it “big enough?”
- Do you start your seeds in your Zone 3 greenhouse in the Spring?
- Is your Zone 3 greenhouse insulated?
- Do you have water and power in your greenhouse?
- How cold does it get in your Zone 3 greenhouse?
- What do you grow in your Zone 3 greenhouse?
- Can you grow food year round in your Zone 3 greenhouse?
- How do you keep your backyard greenhouse cool in the middle of summer?
And don’t miss out on more of my cold climate greenhouse content, linked below!
- 10 Plants That Thrive In A Zone 3 Backyard Greenhouse
- Best Tips For Building A DIY Backyard Greenhouse For Cold Weather Climates
- Why, Where & How We Moved Our 2,000lbs Backyard Greenhouse
Question 1: Is your greenhouse a kit or did you buy it?
Both of our backyard greenhouses have been DIY builds.
I’ve got a full blog post covering all the details here.
We chose to build our backyard greenhouse ourselves for a few reasons, including …
- Wanting something that fit exactly our needs
- An exterior design that was cohesive with the style of our home
- Ensuring materials were durable enough to withstand the extreme weather we get in Zone 3 Manitoba
With that being said, if DIY just isn’t your thing there’s a lot of great kit greenhouse options out there too!
And if we were to add another greenhouse to our property, or didn’t have the funds/abilities for a DIY project as such — I’d probably go with a kit from Planta Greenhouses.
They’re top rated by many Canadian gardeners. Because they can withstand heavy snow and wind.
We’ve bought our shade cloth and a greenhouse heater from Planta over the years. Both are great quality!
All that to say…there are some BAD greenhouse kits on the market too…
And bad in the sense that they will likely not hold up through harsh Canadian winters. Or be able to grow food in them during the shoulder seasons.
I’d avoid any kits that don’t come with a temperature rating!
Question 2: How much did your greenhouse cost?
Ah the most important question — how much did it cost? And probably the most commonly asked question.
I do have a full blog breaking down the cost per material of our DIY backyard greenhouse. You can give it a read here!
But if you’re just looking for quick numbers…
Our first greenhouse (which spoiler didn’t work properly to grow food in for more than 6-ish weeks of the year) cost approx. $1,200 to build.
Inexpensive, yes. But also not functional. So I’d say it wasn’t worth it. Though it did teach us A LOT.
Our second and current greenhouse, which we can now easily grow food in for 8-9 months of the year, cost us approximately $10K to build. This investment has been staggered over several years as we’ve continue(d) to make improvements.
Again, you can find my full blog breaking down our DIY backyard greenhouse spend on all materials here!
Question 3: What size is your greenhouse? And is it “big enough?”
Our backyard greenhouse is 12’x14.’
For us, this is the right size. Because it provides enough space to evolve with the seasons.
In the Spring we set-up seed starting shelves out there and direct sow cold-hardy vegetables in the raised beds. In the Summer it becomes more of a hot house for heat-loving crops like tomatoes, cucumbers and peppers.
Then in the Fall and Winter, we adjust it to overwinter plants that aren’t hardy to our Zone 3 outdoor conditions (like eucalyptus!). We also use it as a bit of a hangout space to get some Winter sun!
I really believe the “right size” for a backyard greenhouse is completely subjective.
It all comes down to your personal goals! And what you want to grow.
Question 4: Do you start your seeds in your greenhouse in the Spring?
The answer to this one is yes and no….
Yes, I start some seedlings in our greenhouse in early Spring. But only cold-tolerant seedlings.
Think salad greens, brassicas, radishes, flower bulbs, etc…
Because we typically don’t heat our Zone 3 greenhouse, it’s not suitable for heat-loving seedlings in the Winter/early Spring.
Any other slow-growing seedlings that need to be started from Jan-April, I keep indoors under growlights.
However, come mid to late April I typically move all our seedlings out to the greenhouse.
So, yes we do start some seedlings in our greenhouse and they thrive in the cooler temps.
Question 5: Is your Zone 3 greenhouse insulated?
This is another yes/no answer! Because we are in the process of finishing insulating our greenhouse.
A few years back, we moved our greenhouse and placed it on an insulated concrete pad. All the details on that here!
Having heat come from the ground and warm our raised bed soil from below made a massive difference!
Our greenhouse not only stays warmer in the shoulder seasons, but it also stays cooler in the Summer months.
The walls of our greenhouse are not yet insulated. That’s the next project on our never-ending to-do list.
Question 6: Do you have water and power in your greenhouse?
Yes, we have both water and electrical lines trenched underground to our Zone 3 greenhouse.
Our greenhouse is about 150ft from our home. So this was a must for us!
Our water llnes make it really easy to ensure we can water everything in the greenhouse with hoses. And our electrical allows us to have fans, heaters, grow lights and anything else that requires electricity.
If you live rurally or plan to position your greenhouse a ways away from your home, I highly recommend you do the same.
Question 7: How cold does it get in your Zone 3 greenhouse?
Okay THIS is a top asked question. And for good reason!
Of course we all want to know, is it actually possible to keep a greenhouse warm in the middle of the Winter in Canada?
So if we aren’t using our greenhouse for anything other than overwintering plants (usually Nov-Jan) it typically hovers about 10-15°C warmer than the temperature outside.
With that being said, we sometimes have days of -35°C and colder. So it can still get too cold to grow anything the greenhouse!
I’ve found that the Winters where we have more snow, the greenhouse stays warmer. Since the snow almost acts an insulation around the base.
The biggest benefit to overwintering plants out here is that they’re protected from the wind. It’s not the cold that impacts them all that much but more so the windchill!
Question 8: What do you grow in your Zone 3 greenhouse?
Another top asked question!
We grow a range of flowers, food crops and houseplants in our Zone 3 backyard greenhouse.
I have a full blog covering our top 10 plants that thrive in a Zone 3 greenhouse linked here.
After a lot of trial and error, I’ve found you really need to adjust what you grow in a backyard greenhouse with the seasons.
For example….
What we grow in the Spring in a Zone 3 greenhouse:
- Cold-tolerant seedlings (brassicas, etc..)
- Salad greens
- Flowering bulbs
- Overwintered herbs and flowers
What we grow in the Summer in a Zone 3 greenhouse:
- Heat-loving veggies (tomatoes, cucumbers, peppers)
- Exotic tropical plants (ginger and turmeric)
- Small fruiting trees (citrus, olives)
What we grow in the Fall in a Zone 3 greenhouse:
- Cold-tolerant veggie crops
- Extend the season for our heat-loving veggies
What we grow in the Winter in a Zone 3 greenhouse:
Overwinter herbs and flowers that are more suitable to slightly warmer zones
Question 9: Can you grow food year round in your Zone 3 greenhouse?
We can grow food for about 8-9 months of the year in our Zone 3 greenhouse. So no, we don’t grow food 100% year round.
We likely could if we chose to heat our greenhouse throughout the coldest months (Dec-Feb). And I would like to try and experiment with that at some point in time!
However, up until now I’ve found we can grow different foods at different times of the year beginning in March and usually going right until mid November.
I have found using the concept of “stacking functions” works really well to continue growing food in the colder months in an unheated greenhouse.
This is the idea of “stacking” various materials to provide plants additional insulation without needing forced air heating.
For example the greenhouse itself is like the first layer. Next you could use a raised bed. A third layer could be heavily watering the bed before a cold night (yes moisture insulates plant roots!). Then a fourth layer could be an insulated heavy-weight row cover laid over top the raised bed. And from there you could throw another heavy quilt or blanket over the entire bed if it’s a really cold night.
Question 10: How do you keep your backyard greenhouse cool in the middle of summer?
I already mentioned in another answer that putting our greenhouse on top of an insulated concrete base actually helped keep it cooler in the Summer months.
If you missed those details, you can find them all in this blog linked here!
But of course, a greenhouse gets hot from the sun. So protecting the tops of your plants is also key.
We’ve found keeping up a high-quality shade cloth (we use this one from Planta Greenhouses) throughout July and August is a must.
It provides UV protection from the sun while also lowering the overall temperature in the greenhouse.
Further to that, good ventilation is essential too. The windows in our greenhouse open so we can get a good breeze flowing through.
Because we live in a pretty windy area, this has been substantial. But you can also invest in roof vents like these that allow hot air to escape.
And there you have it!
There’s the answers to our top 10 most commonly asked questions about our Zone 3 backyard greenhouse.
I hope this helps you plan out your cold climate greenhouse! If you have any further questions, please do drop them in the comments! I love hearing from you and answer all comments.
To see more of our greenhouse & garden, follow me on Instagram @fromsoiltosoul. You can also browse my other blog posts for more organic gardening advice.