Growing plants in a purpose-built indoor environment is increasingly a preferred choice. Even on a mass agricultural scale, tunnels and greenhouses give farmers a competitive edge. Repeatedly, the initial investment has shown excellent returns.
The essential purpose of both hoop houses and greenhouses is to provide plants with a controlled growth environment. Hoop houses are growing in popularity because they are easy to construct, effective, versatile and comparatively cheap.
I’ve decided what works best for me. My facility needs to:
- Be cost-effective
- Be able to deal with our climate
- Be easy to assemble and move if I need it to
- Be functionally adaptable, allowing me to produce a range of products in different formats
I don’t need my growing facility as a value-add, aesthetically pleasing feature on my property. I have opted for a couple of hoop houses on my community allotment stand and have just added a new one – for all the reasons mentioned above. They work very well for me, and in this piece I share why.
Which is More Cost-Effective? Hoop House of Greenhouse
To get the semantic differences out the way, let’s clarify what a greenhouse is. According to the Merriam-Webster dictionary, a greenhouse is “a structure enclosed (as by glass) and used for the cultivation or protection of tender plants.” In this article, the reference to a greenhouse is a structure made primarily of metal (including aluminum) and glass.
The essential feature of a greenhouse are listed below
One of the most important jobs of the cover of your greenhouse is allowing light penetration. Single-layer glazings generally allow 90 percent transmittance and double-layer glazings about 80 percent of light.
An essential difference between a hoop house and a greenhouse is aesthetics. Beauty, however, is a subjective topic. If in doubt, ask you’re significant other. Some of the newer polytunnels, or hoop houses, are pretty exquisite. Still, a classic Victorian-style glass greenhouse on a property is an attractive feature.
Durability – maintenance
Even though both are strong materials, there is a distinction between plastic and glass. Glass is a more durable material than plastic and will endure for decades without showing wear and tear (unless broken). But glass comes at a more significant expense.
Safety glass is used in greenhouses and is nearly as strong as polyester for greenhouses. Don’t worry if your child is playing soccer in the yard or if a rainstorm passes by; greenhouse materials can withstand the elements. Regarding safety, you can’t compare polyethylene tearing to glass breaking.
Is a Hoop House as Good as a Greenhouse, Cost-Wise?
Per square foot, the cost of a greenhouse is approximately eight to ten times that of a hoop house. The argument that a hoop house is less durable than a greenhouse is fast becoming moot. The advancement in fastening and tensioning technologies allows poly structures to stand for decades without tearing. Improved UV protection is further extending the life of plastics.
Which-ever way you look at it, polytunnels, or hoop houses, give you much more back for your buck. For a more detailed cost analysis, please look at our article that compares the two in more detail.
Extending Growth Seasons
This quote by USDA refers:
Tunnels often look similar to greenhouses but are usually only single-walled and are typically not temperature controlled. The plastic covering traps sunlight to raise temperatures inside the structure for the plants growing inside. Gardners can extend the growing season by four weeks by protecting crops from potentially adverse weather conditions. Crops grown inside high tunnels tend to be of higher quality and produce higher yields.
Though hoop houses are often single-walled, adding additional cover layers can further extend your growing season. By creating smaller hoops within the hoop house, use PVC piping over a bed; each layer of polyethylene increases the temperature for the plant by 8 degrees Fahrenheit.
By creating successive layers of protection over your plant, you can increase the temperature by increments of eight degrees Fahrenheit. If your outside temperature is 46 degrees Fahrenheit, by creating two additional internal hoop covers over your plants, you can increase your temperature to 70 degrees Fahrenheit – the optimal temperature for a tomato plant (give or take a couple of degrees)
If done correctly, hoop houses can withstand winds of up to 80mph. You could look at my post Do This To Avoid Your Polytunnel Being Blown Away By Wind – Simplify Gardening for more information on how to do this.
The Noble Research Institute in Ardmore, OK, provides a build-it-yourself polytunnel plan with good anchoring and windproofing precautions. Just a side note: They say it’s portable – I think not. That hoop house there is going to linger longer for a while.
An additional suggestion worth mentioning is the use of ropes to prevent the poly from flapping in high winds. At each cross brace, on either side, run a non-abrasive cord across the tunnel. This increases the tension of the poly and limits its ability to flap. Flapping in the wind increases the wear and will eventually lead to some damage.
The architecture of hoop houses matches the climatic regions. Just as homes in areas with high snowfall have a greater pitch, so hoop houses in places where it snows regularly are different. There are three main design shapes; Quonset hut, gothic arch, and gable designs – a progressive adaption to the severity of snowfall.
Balancing wind dynamics and the ability to shed snow is essential – the higher and steeper you go, the more obstruction you create for wind, but the ability to use gravity to keep the snow off increases.
Quonset Hut Design
Typically, most hoop houses are a Quonset hut design. This design is in the shape of a semi-circle, like a typical bunker. When snow falls on these structures, depending on the width, it will accumulate and requires additional management to remove the snow regularly to prevent it from collapsing.
If you keep your tunnel width to about 8-feet, snow ough not be a problem. The greater the width of a Quonset design, the less acute the arch pitch will be and thus more likely to accumulate heavy snow.
Gothic Arch Design
To alleviate the relative flatness of the semi-circle design, some manufacturers include a 120 degree (or less) join at the top of the arch, creating a gothic-type look. The effect is that, even for wider tunnels, the roof’s pitch significantly increases, making them manage snow better.
The gable design is less popular but does present an option. The join in the center is 90 degrees and even further increases the roof’s pitch. I have had limited exposure to this design, but this may be an option for those living in high snowfall areas.
Is a Hoop House as Good as a Greenhouse, Weather-Wise?
For all intents and purposes, a hoop house is as good as a greenhouse. Regarding whether consideration, greenhouses, being more robust and solid in structure, may have a slight edge on hoop houses. Then again, in winds of 80mph, a solid structure made of glass and aluminum may not do as well as a well-anchored hoop house that has some give and flexibility.
Ease of Assembly
If you watch the video below from my YouTube channel, you’ll see that this 36ft long by 16ft wide tunnel was, for the most part, built single-handedly. Admittedly, I did have some help along the way, but it didn’t need a crew, and I could do most of the work myself.
If you didn’t yet watch the video, here are some highlights from it:
- Remove all weeds from the area where the tunnel is going to be erected.
- Make sure that the ground in this area is level.
- Use the Pythagoras 3-4-5 rule (a triangle with side-lengths of a=3, b=4 andc=5 units respectively, will produce a right angle between a and b) to get your shape squared. The longer the units, the more accurate your square corner. So, making your corner sides a and b 9 feet and 12 feet respectively, then to square them c will need to be 15 feet. (multiply each factor by 3).
- Next, insert the individual hoop holders along the side perimeters as advised by the plan. In my case, it was a distance of 6-feet between each rib.
- Next, I installed the base plates and end supports. Ensure center the shade cloth lengths in the middle of each rib section for use as an insect covering over the vent windows you’ll cut later.
- Assemble the door frame and positioned it to mark where the holes need to be dug.
- Use a string between the outer post to align the doorpost positions. The alignment is critical because the doors are sliding doors, and misalignment will create difficulties later.
- Once the holes are complete, insert the doorposts, align them and backfill the holes. I need to dig about 15 inches for the doorframe to fit.
- Next, I installed the crossbars. Watch the video for detail.
- Install the supports for the crossbars. These add strength to both the frame and crossbar. In the future, we will use the crossbar to suspend our crops, so these need to be robust.
- I then installed the supports for the upper rail, which will support the curtain later. The rails slide into these supports. I positioned these rails a meter above the base plate (3.28 ft, about 3 feet 4 inches).
- Next, I assembled the doors. If you can follow the instructions on a flat-pack, you could build this tunnel. Pretty straightforward.
- Buffer any sharp edges like bolts with some padding tape before pulling the plastic sheeting across. Start from the ends, not the sides.
- Using a wiggle-wire and starting at the top of the door frame, create a starting point that will allow you to tension the plastic across the frame. When using wiggle wire, it is vital to wear safety goggles and gloves to prevent injuries.
- Next, using the wiggle-wire at the base plate, start to fix your sheeting to the sides on both sides. We have a way of making the plastic more taught later, so don’t stress about it yet.
- At the other end, create downward folded pleats when gathering the excess plastic covering. Clip these into the wiggle-wire frame in the back vent and baseplate.
- Cut your windows out. I used a dustbin lid to mark the circle and cut them with a Stanley knife, ensuring no ragged edges.
- Then I attached both the shade-cloth sections and the cover flap over the windows. The handle for the bar attaches easily to enable you to wind the flap up to create ventilation.
Is a Hoop House as Good as a Greenhouse, Build-Wise?
As can be seen from the video above, creating this significantly sized growing space as a hoop house took me a day with limited human resources. Imagine doing that as a greenhouse. Build-wise, a hoop house is streaks ahead.
If you want to see a detailed comparison between polytunnels and greenhouses, you should read this article packed with information and links Polytunnel Vs. Greenhouses. Pros & Cons You Always Wondered! – Simplify Gardening.
Conclusion on is hoop house as good as a greenhouse
The initial question was whether a hoop house is as good as a greenhouse. In my opinion, you could just as easily frame the question the other way around – is a greenhouse as good as a hoop house?
I believe the two are equals, and choosing one over the other is merely a product of intended application, scale and economics. I find the cost of a greenhouse for the scale I operate at prohibitive.
There are industrial-sized greenhouses that operate at a different economic level. These require a considerable investment, and their design are superstructures able to last for many decades.
But for me, hoop houses serve me well.
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