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How to Choose the Best Greenhouse Kit for Backyard Gardeners

Greenhouse Kit Project

Gardening doesn’t have to be just a seasonal fling, take it up a notch this year and let your herb and vegetable goodies ride out the colder months with you in a greenhouse. Provide food for your family, medicine for your ailments and waltz out of winter feeling accomplished (and healthier). Greenhouse kits make setting up a year-round garden easy and we think it’ll be an investment you won’t regret making.

Why Buy a Greenhouse

I know a lot of gardeners who question whether or not this is the year they’ll throw down and get a greenhouse for their backyard. Another year comes and goes and still, they wonder… should I?

If this sounds like you it’s probably about time you get serious about adding a year-round garden space to your yard. Because you’re not getting any younger (sorry) and your love for gardening probably isn’t waning.

Plus, you can reduce food costs and feed that survivalist hankering you don’t want to admit is there. With a greenhouse not only can you keep your warm-weather plants thriving into the holiday season, you can start your seedlings early and experiment with growing new and exotic plants in a controlled environment. (Think dwarf banana tree or passion fruit.)

And if your green thumb can handle it, you could make a few extra bucks (or some new friends) if you have a crop surplus.

Is it worth it?

There is part of you saying -- I don’t know, aren’t they kind of expensive and hard to maintain? And yes, you could be right about both of those things depending on what kind of greenhouse kit you buy, where you live and what you plan on doing with it. A quality greenhouse kit gives you all the pieces you need to have a successful grow - as long as you know what attributes are important for you. We will discuss this shortly.

Advantages of Greenhouse Kits Over DIY

In some ways buying a greenhouse kit is DIY. You know, you get to take the do-it-yourself maxim and apply it to assembling your new kit when it arrives, instead of hunting down the right-sized pieces of everything to only cross your fingers and hope it pans out. (Many of my own DIY experiences live here.)

With a kit, you do a little research -- or heed our advice -- click a couple of buttons and then spend a couple of hours with friends and family assembling it into existence. I’d say if you’re someone who wants to spend more time gardening than being an architect then a greenhouse kit is for you.

Of course, in order to prevent an ill-suited greenhouse kit purchase, you should become familiar with the pieces that invariably make up a greenhouse kit and identify which ones will suit you best.


How to Choose a Greenhouse Kit

Buying a greenhouse can be incredibly rewarding or incredibly frustrating (like a lot of things in life). The last thing you need is to get your kit setup just to have it collapse under a mediocre snow, right? Let’s unpack what to look for when you choose a greenhouse kit.

Frames

Greenhouse kits are made with several frame options. From the least expensive PVC hoop houses to the most expensive and durable Solexx composite frames.

Solexx
Solexx composite frames combine PVC, steel and combination composite tubing -- the same material that bridges are made from -- which ensures durability and longevity even through the harshest of conditions. Solexx frames have higher R-value and lower U-values (insulating ability and measurable heat loss, respectively) than the other frame options on the market. But, like anything, quality demands higher costs. If you’re really serious about growing year-round and live in an unforgiving climate, Solexx may be the best option for you (albeit quite expensive).

60 mph winds & Snowstorm Can't Take Down Solexx (1:27 mins)

Aluminum
Probably the most popular frame that comes in greenhouse kits. It’s cheaper than a composite frame but not as flimsy as a resin or PVC frame - and it literally shines. A nice addition to the yard decor for some. They are easy to assemble and the frame won’t rust or rot like steel or wood. Check the strength rating before purchasing if your area sees heavy snowfalls. Aluminum frames can be anchored to the ground for windier regions, but if it’s too windy you should consider wood or solexx.

Wood
Another very popular material for greenhouse frames. It’s not too expensive and it’s strong (plus it can be serious rustic eye-candy for the garden). The downside is managing wood rot and staving off diseases that can impact your plants and the integrity of the frame. To reduce maintenance and the prevalence of rot, seek out high quality wood like cedar and redwood.

Resin
Resin is plastic and another go-to material for building a greenhouse. Some companies use recycled resin which is appealing to the eco-friendly gardeners amongst us. If you decide to go with plastic, choose a light colored frame to detract the sun’s heat which can cause warping and degradation.

PVC
The least expensive and easiest to set up of them all: PVC houses. Most PVC greenhouses are called hoop houses as they resemble a series of plastic hoops covered with a tightly pulled sheet of fabric that fastens into the base of the house. Hoop houses will help manage the climate inside for your plant babies and keep away intruders but in the case of strong winds and harsh winters, hoop houses aren’t the most durable. Double-check that the PVC is UV treated to prolong its life.

Glazing

Glazing is just a fancy word for the material-that-covers-your-greenhouse-frame. What kind of greenhouse glazing you choose really depends on where you live (your climate, altitude, sun availability), the orientation of your greenhouse (north facing, east facing), what you want to grow, your budget and how you want the finished product to look.

Here are two things you should know before choosing a glazing.

Thermal insulation (R-value). The higher the R-value, the more energy efficient the glazing is. For example, double pane glass has an R-value that sits somewhere around 2, while single pane glass hovers around .93. Therefore, we can deduce that single pane glass is less energy efficient than double pane.

Light transmission %. The percentage of light that makes it through the barrier (glazing) without being reflected or absorbed is the light transmission percentage.

The higher the light transmission percentage, the more light your plant gets. The more light your plant gets, either the healthier it grows or the more it gets burnt (and so do you). If you’re in a full sun area a lower light transmission percentage may be better for you (70-75%). Partial sun you want to be in the 90’s. The more diffusion of light that occurs the more evenly distributed the light will be inside the greenhouse.

Materials

Commonly used glazing materials include Solexx, glass, polycarbonate and polyethylene. Fiberglass and acrylic are far less popular now due to quicker degradation and less light transmission than polycarbonate.

Solexx. An opaque high insulation value, low light transmission option for a serious hobby gardener. It’s going to cost extra but the diffusion of light is primo (no hotspots) and insulation is at its best.

Glass. While easy on the eyes, glass can be an expensive and not-so-energy efficient glazing option. Glass can come in single or double pane, with single pane being the least energy efficient of all glazing types. If you’re in a colder climate the single pane insulation value is low which will hike up your energy costs as you try to supplement leaking heat. And single pane glass is prone to hotspots -- uneven distribution of heat -- which can damage plants. Double pane glass will reduces heat loss, has a longer lifespan, evenly distributes heat and can help your plants thrive.

Tempered glass is favorable as glass can break from seemingly-blind birds, downed branches from storms, heavy snows, or other hapless events.

Multi-wall polycarbonate. Multi-wall polycarbonate is one of the most popular glazing options for greenhouse owners worldwide. Similar to double pane glass it is energy efficient and reduces the likelihood of hotspots. Unlike glass it can be beat with a hammer without breaking (if you really wanted to), lasts longer and is more cost efficient with an equally high overall R-value.

Polycarbonate is a rigid plastic with a transparency akin to glass (light transmission of more than 92%). Plastic thickness can range from a 4mm twin-wall to a 16mm five-wall -- depending on your needs and budget. It’s not as stylish as glass, but holds its own in function and cost (which arguably is more important).

Corrugated polycarbonate sheets. A step down from multiwall polycarb we find corrugated polycarb sheets. These sheets are often used for roofing and siding material as they are lightweight, weather resistant, virtually unbreakable and available at a reasonable cost. Most manufacturers offer some kind of warranty against discoloration (known as the yellowing index) for up to ten years. Also look to see that light transmission is above 90% and that the sheets are UV protected.

Polyethylene film. If you are on a shoestring budget poly film can give your plants some climate protection and keep some of the pests out. It degrades quickly (1-6 years) and offers little insulation.

Ventilation

Just like glazing and frame choice is important, it’s crucial to ensure that your greenhouse has proper ventilation. You don’t want to cook your plants in the summer. One roof vent on either side of the roof ridge covering about 20% of the floor area is ample ventilation. Side vents are also useful but should not be used as roof vent replacements. It's also necessary to make sure the plants don't freeze in the winter by adding heat in colder climates.


Considerations Before You Buy

Site. Where you put your greenhouse is crucial to deciding if you should even get a greenhouse. If you’re yard is fully-shaded you may want to consider a greenhouse lean to where you can easily provide supplemental light from your house. Likewise, if your greenhouse site is too exposed it could cost way more to keep cool in the summer and be subject to wind damage. Pick a site with southern exposure with six hours of light a day.

Proximity. The best laid plans can still lead to sort of what-have-I-done kind of mess. Map out a place for your greenhouse that is 1) close to water and electricity and, 2) free of obstacles so you can easily get in and out with a wheelbarrow, back a truck up, have a gardening party - whatever it is.

Foundation. Not everyone will need to pour a concrete foundation for their greenhouse. But people who live in colder climates may want to consider this add-on to keep heat in the greenhouse instead of disappearing into the cold, cold earth. Also, make sure that you carefully choose an area where water doesn’t collect.

Drainage. Don’t expect to just tie your greenhouse to the ground and call it a day. You’ll need to ensure proper drainage by digging a trench, or using gutters to prevent soil from becoming oversaturated and becoming a breeding ground for algae and disease.

Local regs. Unfortunately some jurisdictions don’t want to see a bunch of little garden homes popping up all over the place (blasphemous, I know). Associations like the HOA and local laws can interfere with where you want to put your greenhouse, how big it can be, how close it can be to your house or the street and so on. Check in with your regional zoning office to hear what they have to say before sinking a bunch of money into something that gets you in trouble.

So now that you know all about the what and why about picking a greenhouse, here are some of our greenhouse kit recommendations.


Greenhouse Kit Reviews

Large Backyard Greenhouse Kits

Large backyard greenhouse kits tend to hover between 50-70 square feet. They are a good size for serious hobby gardeners or someone who is looking to become one. All of the kits are walk-in units with enough room to work and enjoy without feeling cramped.

Palram Nature Series Mythos Hobby Greenhouse

Pros:
  • Attractive silver aluminum frame with galvanized steel base which helps give the unit stability during inclement weather
  • 4mm twin-wall polycarbonate glazing with 99% UV protection increases diffusion of light to eliminate hotspots
  • 48 square feet of growing space with enough overhead room to walk in and out comfortably
  • Can withstand high winds (up to 70mph) and more than 4 feet of snow without leaking, buckling or showing any sign of weakness
  • Magnetic latch and lockable door add security and convenience to the greenhouse
  • 2 adjustable roof vents improves air circulation and ventilation
  • Good quality polycarbonate for living in high-altitude homes (no sun burn)
  • Gutters that run lenth-wise along the A-frame roof help water drainage
Cons:
  • No shelves are included with the unit, you must buy them separately
  • The glazing isn’t as tight as it could be which leaves a few gaps where bugs, air and water can get in (easy to fix with tape)
  • Assembly is taxing as it includes a lot of pieces, poor directions and often is missing a piece or two -- nothing that customer service won’t fix. Allow a full day to get it up.

Rion EcoGrow 2 Twin Wall Greenhouse

The EcoGrow 2 can come as a 6’ x 6’, 6’ x 8’, 6’ x 10’ or 6’ x 12’ - appealing to a wider variety of people. Consider a concrete or timber base before erecting this greenhouse.

Pros:
  • The unit roof is made of a 4mm twin-wall polycarbonate glazing with 90% light transmission, the unit sidewalls are made of 6mm twin-wall polycarbonate -- thicker walls to protect offer better impact resistance
  • Frame is made of 100% UV protected resin to reduce degradation from the sun
  • Roof is a familiar barn slope which gives a lot of head room for gardening inside and can help relieve the weight of heavy falling snow
  • You can purchase an optional base kit (this could be good that it’s available or bad that it’s not already included).
  • Rated for winds up to 80mph which could give you peace of mind if you live in a windy place
Cons:
  • Hardware for mounting unit to a foundation does not come with the unit, however there are pre-drilled holes
  • Only one roof vent which doesn’t give a ton of ventilation
  • No place to fasten irrigation lines inside the unit
  • Assembly is no easy task, allow a full day (or two) to piece this bad boy together. The instructions are little to no help and don’t include words -- only diagrams.

Palram Snap & Grow 8' Series Hobby Greenhouse

Pros:
  • Polycarbonate glazing that is impact resistant, 100% UV protected and 90% light transmission
  • Frame is made of 100% UV protected resin to reduce degradation from the sun
  • 68 square feet total gardening space
  • Double doors with lockable handles adds an extra layer of security
  • The kit comes with skirts to cover the 6x8 wood wall we recommend you secure to a concrete foundation if you live in high wind areas
  • The roof is equipped with gutters to help discharge rain in high precipitation areas
  • One sturdy and adjustable roof vent allows for ample ventilation (there is an automatic version but it is not included)
Cons:
  • Not totally bug proof so if bugs are a concern you will need to take some measures to seal up the door and roof vent area
  • The pieces don’t all fit flush, especially around the door where there is noticeable sagging
  • Assembly takes between 3-6 hours depending on how astute you are at deciphering a confusing manual
  • There is no way to attach shelving to the corners of the unit unless you Macgyver it
  • The door hinges that come with the unit aren’t the best quality, it’s possible you’ll want to replace them
  • The anchoring kit is a separate purchase (but highly recommended as the greenhouse is lightweight for its size)

Flower House FHSP300CL SpringHouse Greenhouse

Pros:
  • Gro Tec clear PVC glazing is very durable, 100% UV protection and has good impact resistance
  • Pop-up assembly can be done in under 20 minutes (think about it like a folding clothes rack assembly)
  • Seems to hold up quite well under strong winds -- 40mph -- without any rigging (although, to be sure, think about using cable ties to secure it to a structure). Unit does come with ground ties
  • Greenhouse has open bottom so you can place it over in-ground plants for the winter, or place it on a foundation to use with shelving
  • Equipped with screen door and solid plastic door for premium ventilation while still keeping the bugs out
  • Very roomy inside even for the serious gardener at 6.6' x 6' x 6'
  • Unit designed with four portholes to accommodate hoses and cable cords
  • Long life-span for this price point with average being 4 years of use
Cons:
  • Frame is a bit flimsy and off-centered (the plastic covering is not aligned with the frame which could cause some tearing and wearing of the seams over time)
  • Should use a small space heater if temperatures drop below 30 degrees as the greenhouse isn’t very insulated (and it appears that the plastic glazing will begin to crack under sub-freezing temperatures)
The winner: Palram Nature Series Mythos Hobby Greenhouse

We chose the Mythos hobby greenhouse as the winner for a few reasons. First, the 4mm twin-wall polycarbonate glazing has a 90% light transmission rate which is important to protect your plants from heat loss and potential burning. It makes for a good greenhouse in high-altitude as long as you don’t keep the unit in full-exposure sun. The A-frame roof allows for snow and rain to easily roll off into the included gutters for easy and painless water drainage. You don’t have to worry about the greenhouse collapsing under the weight of feet of snow or toppling due to heavy winds (because they include anchoring hardware, unlike the others).

The other large greenhouse kits here came equipped with only one adjustable roof vent which isn’t enough to properly ventilate a greenhouse of this size. The Mythos has two vents and a screen door for adequate circulation (and a way to keep the bugs out). The attractive aluminum frame wins over the competitors resin frame, and what really sets Mythos apart is the galvanized steel base for added support.

Sure, assembly is a bear for the greenhouse but for the price point and the quality, it’s worth putting in a full day with friends to get it up. Expect many years of good use out of Parlam’s greenhouse kit.


Mini Greenhouse Kits

Gardman R687 4-Tier Mini Greenhouse

This kit can be assembled and live right on a balcony, deck, or in a townhouse backyard. We found the footprint is a bit big for indoors, but if you have space it could make a great addition to your kitchen (with an herb garden, of course).

Pros:
  • Compact greenhouse at just under 12 lbs and 27” long x 18” wide x 63” high
  • Poly film glazing that zips and rolls-up for easy access
  • Four metal lattice shelves -- which allow sunlight to filter through from shelf-to-shelf
  • Sturdy enough to hold two 5-gallon pots on a shelf
  • Assembly takes less than a half hour and you don’t need any serious tools
  • More affordable than other greenhouses with its size and quality
Cons:
  • The shelves can be unbalanced so you may need to buy cable ties to hold them into place
  • The whole frame is a bit flimsy and pretty lightweight so you’ll need to put some bricks or books in the bottom to weigh it down to prevent wind damage

Ogrow Ultra-Deluxe 4 Tier Portable Bloomhouse

A portable mini-greenhouse for an urban gardener or beginner hobby gardener.

Pros:
  • Small footprint greenhouse kit at 11 lbs. and 27" x 19" x 62" 
  • Sturdy shelving despite lightweight overall feel of the frame -- holds up to 75 lbs on each shelf
  • Heavy plastic glazing that can withstand poking and prodding, hail and some battering
  • Durable powdered steel coated metal frame with plastic connectors for secure joints
  • Withstands temperatures in the low twenties without needing supplemental heat, which is better than its competitors
  • Assembly only takes about 15 minutes with the velcro hook and loop system
  • Easy to move from inside to outside for more or less sunlight
Cons:
  • The shelves are not adjustable so fitting taller plants can be an issue, but you can take out one or two shelves to allow for more room
  • There is no built in ventilation aside from rolling up the plastic cover so plants can bake in the heat quickly if the cover is closed (or you don’t slit a couple of holes in the top of the unit yourself)
  • No hardware included to stabilize the unit or the shelves for windy weather

VonHaus 4 Tier Portable Mini Greenhouse

Pros:
  • Sturdy and durable steel frame
  • No tools required for assembly and can be setup in about five minutes
  • The clear PVC glazing is weather resistant and has enough slack around the unit to not impair the zipping ability (or wear the zipper down from pulling material)
  • The plastic cover (glazing) can be rolled up and secured to allow for ventilation
  • Holds moisture and heat really well for the winter months and maybe a little too well for the summer months
Cons:
  • Wire shelves can only hold up to 18lbs - a quarter of the competitors weight threshold.
  • Large mesh squares leave small pots unbalanced or unable to sit without a tray underneath
The winner: Ogrow Ultra-Deluxe 4 Tier Portable Bloomhouse

The Ogrow felt like an obvious choice for us because it’s durable, compact and has a few features that seem like a no-brainer for a mini-greenhouse kit. Mainly, the ability to hold up to 75 lbs per shelf, the strong steel coated frame and the hardier plastic glazing. For a greenhouse that has the potential to be portable -- you need a unit that isn’t going to crumble with 3mph winds. The only drawback to the Ogrow is the lack of ventilation, but we felt that this was an easy enough fix at home, and wouldn’t be worth not purchasing a quality unit over. Cut a couple of slits in the top of the greenhouse for ventilation to compensate.

Another reason we chose the Ogrow is it seems to fare better in sub-freezing temperatures that the others. It holds heat and humidity well and would be appropriate as a permanent fixture outside instead of a portable in-and-out, if you so chose. The price is reasonable and assembly is a breeze with the velcro hook and loop system, so no fussing over a confusing manual.

Conclusion: Parlam Mythos Hobby House Wins Overall

Choosing a greenhouse can feel like a daunting task, but it doesn’t have to be. You now have the ability to make an educated decision instead of a fly-by-night purchase. In the end, we recommend the Parlam Mythos Hobby House. The quality of the kit is unsurpassed by competitors in the price range and your plants are sure to have the protection they require to flourish and space to grow to their full potential all without sacrificing light quality.

The double roof ventilation system is key for healthy stimulated plants and the screen door provides a much needed side vent to circulate lower air for a breathable and temperature moderated growing experience.

The kit will be easier to assemble then spending a weekend trying to complete a DIY project, and in the event you have trouble customer service is standing by to answer questions or send replacement parts should you need them. We really think it’s the best bang for your buck.

For a lot more great gardening tips, see our guide on 31 Ways to Make You an Organic Gardening Guru.

About the author

Brittani Sponaugle

Brittani is a content marketer and web designer with over 5 years of experience across many industries. She spends her free time traveling, studying natural medicine + nutrition, mushroom hunting, learning how to cook worldly dishes, and doing photography.

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