Its that time of year again. You have the itch, and you can't stop thinking about what it would be like to walk outside through the snow and ice into your very own greenhouse. You imagine what it would be like to grab a handful of sun warmed soil, and breath in the smell of life. Naturally, these thoughts bring you to the idea of building or purchasing a greenhouse structure; after all, nothing is better than feeling that exciting first step from the cold tundra of winter into the safe warmth and company of vibrantly healthy plants.
In this post, we go over the 7 crucial questions you should answer when trying to determine the size, type, and process for selecting and building your greenhouse.
If this describes you every year during the colder months then you aren't alone.
Framing the Discussion About Your Greenhouse Structure
It is easy to do a quick Google search, and find yourself at a blog post with a title such as "How I built a Greenhouse for $50", but far too often posts like this neglect many of the vital questions one should ask themselves when trying to decide what type of greenhouse structure is right for them. After all, you want a greenhouse that won't blow away in the first wind.
With the above being said, maybe that $50 structure is right for you, but maybe that structure is just a little too small, or needs to be modified to last more than a month in your climate. Or, maybe the blog post you were reading earlier today assumed you already had 90% of the raw materials for the build laying around your backyard.
No matter what type of structure is best for you, this post intends to provide you with a set of starting questions to lend some additional guidance when planning your greenhouse build.
The Guiding Questions for any Greenhouse Build
Here is a quick rundown on the most important questions you should ask when planning your greenhouse build (yes, we have updated the post to include even more important questions to consider):
- What do I want to grow in my greenhouse?
- How much do I want to yield out of my Greenhouse?
- What am I going to do with the harvests from my greenhouse?
- How am I going to balance cost of the structure vs quality of structure?
- What material should I use to frame my greenhouse?
- What type of greenhouse plastic would work best with my greenhouse?
- Based on how I answered the other questions, what is my greenhouse budget?
The way you answer these questions will help organize what size, type, and budget you will have for your greenhouse build.
How to Answer These Greenhouse Planning Questions
You know you want a greenhouse, and more than that you are determined to have one, even if it is an inexpensive DIY type of structure. Below we go into more detail as to what you should ask (and answer) before trying to decide which path to follow in configuring your covered growing space. If you have already taken the steps to answer the five questions outlined in this post, you should:
Consider reading: How to Build a Large Hoop House: Material Selection and Configuration
If you want additional guidance on how to come to answer the questions outlined in this post, check out each bold headed question below.
1. What do I want to grow in my greenhouse?
Your answer to this question will tell you a great deal about any given structure you want to make, or purchase.
If you answer that you are going to grow arugula we know that arugula can be planted densely and that you may not need a huge greenhouse.
On the other hand, if you answer that you plan on growing tomatoes, this is also a telling statement. In this scenario you will be growing plants that require a lot more area, as well as volume, since they can grow all the way up to the top of a greenhouse (and then some).
This question is designed to give some starting direction on how large a structure you will need.
2. How much do I want to yield out of my greenhouse?
This question intends to dig a bit deeper into how large your structure should actually be. If you are growing arugula that is one thing, but if you are planning to grow arugula for all of the restaurants in your city, more space is likely necessary despite the fact that arugula is a densely planted crop.
If your farm runs a Community Supported Agriculture (CSA) program where you provide a bag of produce each week to your customers, maybe you will look at the greenhouse as a way to produce a specific quantity of specific crops during the cold months of the year. With this goal in mind, you can do some rough calculations for the square footage needed in the greenhouse in order to produce the quantities necessary to provide the desired portion of your weekly CSA shares. What these yields are would be dependent upon your CSA, and your plans for future growth.
Maybe you are growing just for your family though, and this greenhouse will be the final piece needed to round out your homestead. Only you know what kind of produce and yields would be needed for your family, but brainstorming these needs will help refine a little further what kind of greenhouse space you should seek out.
3. What am I going to do with the harvests from my greenhouse?
This one is important because the answer will tell you how much is riding on the successful harvests from your greenhouse or hoop house. In other words, is your livelihood relying on the successful production of a lot of food? If so, maybe some additional ventilation features would be beneficial as a part of your structure to ensure a disease free crop.
Are you going to be canning the produce? If so, maybe additional ventilation is still important, but at the end of the day since your livelihood isn't riding on the produce grown in the structure, you decide to wait a season to see if you need to add this feature to your package.
Are you going to be starting plants in the structure? Maybe this is the sole purpose of this greenhouse, and you will, without a doubt, require a heating element as a part of your structure.
Regardless of what you are going to do with your harvests, having a direction for the items you are growing in your hoop house, high tunnel, poly house, or greenhouse will ultimately give you a lot of information about the way your structure should be configured.
4. How am I going to balance cost of the structure vs quality of the structure?
Answering this question, in a lot of ways, is a trade off. The less attention you want to pay to the climate control of your structure and the maintenance of your structure in inclement weather will likely be a trade off with the cost of the structure when configuring what components you want to include.
For example, thermostatically controlled everything sounds nice, right? While this route may make sense to some growers, it may be cost prohibitive for others. That cost is monetary and up front, while having to open shutters manually and roll-up sides will cost more time throughout the life of the structure. Finding a compromise for these trade offs is what this question is all about.
This trade off holds true when deciding what type of framing and bracing is right for your structure. Although Tunnel Vision Hoops LLC doesn't sell PVC greenhouses, some people may decide that they want to make their structure framing out of PVC. While this is cheaper up front, the risk of complete structure failure in wind, snow, hail, etc. is much greater. To avoid these future problems, to sleep better during snow storms, and to have a stronger structure it may make sense to invest in more robust steel framing. Again, this is a trade off that you personally need to come to a comfortable resolution around.
Everyone is different, and regardless of how you decide to build your structure, answering this question will not only point you in a more clear direction, it will allow you to move confidently toward that solution because you have answered the uncomfortable questions about quality vs cost. Whatever you pursue, after answering this question, you should know that it is the right pursuit for you.
5. What material should I use to frame my greenhouse?
This is a big question to answer since the type of framing you choose will determine the strength of your structure.
The main framing materials used in greenhouse builds are aluminum, PVC, and galvanized steel tubing. If you are just building some protection over a single bed or two, and you consider this project an experiment maybe PVC would suffice for you. That said, be aware that PVC has two major drawbacks:
- PVC greenhouse framing is more likely to collapse in snow or break in wind
- PVC greenhouse frames react poorly with greenhouse plastic, and you will be replacing plastic more
A galvanized steel tube framing is the most widely used, and longest lasting greenhouse framing material on the market. Whether you plan to bend your own tubing, or purchase a pre-configured greenhouse DIY Kit, it is worth strongly considering the benefits of a stronger framing material if you plan to have your structure for longer than a year.
6. What type of Greenhouse Plastic would work best with my structure?
There are a number of guidelines you should follow when deciding the type of plastic to cover your structure with. Mainly, how long do you want it to last, and what is your budget.
If you only need your structure to last a year overwintering film can be used to cover your structure. This type of poly is inexpensive, but it will certainly break down VERY quickly compared to other available greenhouse plastic films.
If you want to have a cover that you can be confident in we recommend 4 year 6 mil Greenhouse Plastic. There are a variety of 6 mil plastic types, but the two main product classifications for 6 mil plastic are outlined in more detail below:
UVA Clear Greenhouse Plastic
-Usually these are between 88% and 92% light transmission
-Lasts 4 years when installed correctly, and I have seen some last much longer than this
-Used as the exterior layer in double layer inflated systems
-marked to denote which side faces the inside of the structure
IRAD Greenhouse Plastic
-Typically has a slightly lower light transmission than UVA Clear Greenhouse Plastic
-Has a higher thermicity percentage, which means it holds temperatures a bit better
-Lasts 4 years when installed well, and I have seen some last much longer than this
-Used as the interior layer in double layer inflated systems
-It always comes with markings for which side of the structure is to face the inside
We provide a lot of greenhouse plastic to growers all over the US and Canada, and we have found that the two types of 6 mil plastic listed above do well in pretty much any climate.
6 mil plastic is by far the most popular covering, most likely due to the fact that it the most affordable cover that will last any reasonable period of time.
The 6 mil poly also tends to be very versatile, by which I mean these plastics can work in double layer inflated set-ups, single layer covered structures, end-wall coverings, and more.
7. Based on how I answered the above questions, what is my greenhouse construction budget?
If you are independently wealthy and you can afford a giant greenhouse with all auto everything, that is great, but it may not mean you need to spend all that money. The answers to all of the questions outlined above should give some guidance on the size of your greenhouse, the features included as a part of your structure, as well as the way your design will tackle the price-to-labor trade off presented above.
The Final Steps in Making your Greenhouse Dreams a Reality
Now that you've asked the five most basic questions, and hopefully discovered answers for them, you can now begin to move the hypothetical to reality, and begin asking other questions regarding where your tunnel should be placed, what is the best type of ventilation for a structure of your size, and more. At this point it may make sense to check out some of the standard offerings we have available as a part of our standard greenhouse offerings.