Gardening doesn’t have to be merely a seasonal fling, so this year take it up a notch and let your favorite herbs and vegetables ride out the colder months with you in a nice warm greenhouse. Greenhouse kits, once assembled, make setting up a year-round garden fun and easy and for the constant gardener, greenhouses provide a way to be with your beloved plants come rain or come shine.
While building a foundation based greenhouse may be cost prohibitive for many, a greenhouse kit may be just the less-expensive alternative you've been looking for. At Organic Daily Post we took an in-depth look at some of the more popular greenhouse kits available, both large and small, and want to share our findings with you.
With a greenhouse, not only can you keep your plants thriving into the holiday season, you can even enjoy the beauty of home grown flowers and vegetables in the dead of winter. Plus, if you grow enough, you can reduce food costs by harvesting your own fresh vegetables and herbs. For a little fun, you can start your seedlings early or late and experiment with growing new and exotic plants in a controlled environment (think dwarf banana tree or passion fruit).
A quality greenhouse kit gives you everything you need in order to enjoy your garden through a seemingly endless summer.
Advantages of Greenhouse Kits Over DIY
In some ways, buying a greenhouse kit is still a DIY (Do It Yourself) project. It is hands-on from the beginning. You choose the size, the design you like and even the placement of where it will stand.
The beauty of a kit is that you get to spend some fun time doing a little research to find the the greenhouse that best suits your needs from size to style to functionality. We've taken the first step for you by researching and gathering the info on some of the best greenhouse kits available on the market today that will save you time and perhaps even some money so let's get started.
Let’s go over what to look for when choosing a greenhouse kit.
Greenhouse kits are made with several frame options. From the least expensive PVC hoop houses to the most expensive and durable Solexx composite frames.
Let's take a deeper look into these viable options.
Solexx composite frames combine PVC, steel and combination composite tubing -- the same material that bridges are constructed of which offers durability and longevity through all manner of inclement weather. Solexx frames have higher R-value and lower U-values (insulating ability and measurable heat loss, respectively) than some other frame options on the market. But, like anything, quality demands higher costs. If you live in an unforgiving climate but want to garden year round, Solexx may be a nice option for you.
Aluminum is undoubtedly one of the most popular frames in greenhouse kits. It’s light weight, less-expensive than a composite frame but not as flimsy as a resin or PVC frame - and it literally shines. These kits are are fairly easy to assemble and the frame won’t rust or rot like steel or wood might in time. 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 might want to consider wood or Solexx. Do your homework and ask a professional what they recommend for your area.
Wood is another very popular material for greenhouse frames. A good tip is to use a high quality wood like cedar or redwood. Most wood being used outdoors these day is pressure-treated and comes ready to face the elements.
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 among 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.
The least expensive and easiest to set up of them all: PVC greenhouses. Most PVC greenhouses are called hoop-houses as they resemble a series of 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 plants and keep away insect invaders 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 is just another 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 and personal choice. 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, are all considerations you should make before purchasing a greenhouse kit.
Here are two things you should know about choosing a glazing before you buy.
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 accurately deduce that a double-pane glass is twice as energy efficient as a single-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. If you’re in a full sun area a lower light transmission percentage may be better for you (70-75%). With 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.
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 offers opaque high insulation value with a low light transmission option for the hobby gardener. It costs a little extra but the diffusion of light is excellent with no hot spots.
Glass can be an expensive and a 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 hot-spots and uneven distribution of heat which could theoretically damage plants. Double pane glass reduces heat loss, has a longer lifespan and evenly distributes heat that can help your plants to thrive.
Tempered glass is favorable as standard glass can break from seemingly-blind birds, downed branches from storms, heavy snows, or other unforeseen events.
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 hot-spots. Unlike glass however, polycarbonate can be struck with a hammer without breaking, 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.
Corrugated Polycarbonate Sheets
A step down from multi-wall poly-carbonate. 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. Additionally, look to see that light transmission is above 90% and that the sheets are UV protected.
If you are on a shoestring budget poly film can give your plants some climate protection and keep some of the pests out. The downside is that it degrades quickly (within1-6 years) and offers little insulation from serious cold or heat.
Just as glazing and frame choice are important, it is 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.
Where you construct your greenhouse can be paramount to its effectiveness and for the overall aesthetics of your garden home. If your yard is fully shaded you may want to consider a greenhouse lean where you can easily provide supplemental lighting through electricity from your home or garage. 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 that gets at least six hours of sunlight per day.
The best laid plans can still lead to a what-have-I-done kind of mess. Map out a place for your greenhouse that has ready access to water (if you have to haul it) and electricity (extension cords) and one that is free of obstacles so you can easily get in and out with a wheelbarrow, back a truck up to or for the carrying in and out of plants.
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. Also, make sure that you choose an area where water doesn’t collect around your greenhouse.
You’ll need to ensure proper drainage by digging a trench, or using gutters to prevent soil from becoming over saturated and becoming a breeding ground for algae and disease, not to mention the lure of mosquitoes.
Unfortunately, in some cases there are those in authority that don’t want to see a bunch of little garden homes popping up all over the neighborhood. 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 with your regional zoning office before sinking a bunch of money into something that may be in violation of local zoning laws, codes, or neighborhood restrictions. Failing to do so first has the potential to cause you problems after you have built and you don't want that headache.
The following are some of our best greenhouse kit recommendations.
Large backyard greenhouse kits tend to be between 50 and 70 square feet in size. This kit is large enough for hobby gardeners and serious gardeners alike. You can grow an exciting variety of flora within these walls. All of the kits we reviewed are walk-in units with enough room to work and enjoy gardening without feeling cramped.
- Attractive silver aluminum frame with a galvanized steel base which helps give the unit stability during inclement weather
- 48 square feet of growing space with enough overhead room to walk in and out of comfortably
- Can withstand high winds (up to 70mph) and more than 4 feet of snow without leaking or buckling
- Magnetic latch and lockable door add security and convenience to the greenhouse
- 2 adjustable roof vents improve air circulation and ventilation
- Good quality polycarbonate which is excellent for living in high-altitude homes (no sun burn)
- 4mm twin-wall polycarbonate glazing with 99% UV protection increases diffusion of light to eliminate hot spots
- Gutters running length-wise along the A-frame roof line help with water drainage
- 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 might get in (easy to fix however with tape or weather appropriate caulking)
- Assembly can prove challenging as the kit includes many pieces along with somewhat vague directions. Plan on spending a full day to get this greenhouse up.
The EcoGrow 2 can come as a 6’ x 6’, 6’ x 8’, 6’ x 10’ or 6’ x 12’ - offering a wider variety of size choices. Consider a concrete or timber base before erecting this greenhouse.
- 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 offer better impact resistance
- 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
- Optional base kits are available for purchase
- Rated safe for wind speeds up to 80mph
- Frame is made of 100% UV protected resin to reduce degradation from the sun
- Hardware for mounting the unit to a foundation doesn't come with it, however ,there are pre-drilled holes
- Only one roof vent which doesn’t give quite enough ventilation
- No place to fasten irrigation lines inside the unit
- Assembly is no easy task, allow a full day (or two) to assemble this one. The instructions are of little as they don’t include words, only diagrams
- 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 which we recommend you secure to a concrete foundation if you live in high wind areas
- The roof is equipped with gutters to help disseminate rain
- One sturdy and adjustable roof vent allows for ample ventilation (there is an automatic version but it is not included)
- Not totally bug proof so if insects 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 we saw 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
- Gro Tec clear PVC glazing is very durable, offers 100% UV protection and has good impact resistance
- Pop-up assembly can be done in around 20 minutes
- Seems to hold up quite well under strong winds (40mph) without any rigging (although, to be sure, consider using cable ties to secure it to a structure). Unit comes with ground ties
- Greenhouse has an 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 a screen door and solid plastic door for premium ventilation while still keeping the bugs at bay
- Very roomy inside at 6.6' x 6' x 6'
- Unit designed with four handy portholes to accommodate hoses and cable cords
- Long life-span for this price point with the average usage time being around 4-years
- Frame is a bit flimsy and somewhat off-centered (the plastic covering is not aligned with the frame which could cause some tearing and wearing of the seams over time)
- Consider a small space heater if temperatures drop below 30 degrees as this greenhouse isn’t very insulated (it appears that the plastic glazing may begin to crack under sub-freezing temperatures)
Our Favorite Greenhouse Kit
We chose the Mythos hobby greenhouse as our favorite 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 higher-altitudes as long as you don’t keep the unit in full-exposure to the sun.
The A-frame roof allows for snow and rain to easily roll off into the included gutters. You don’t have to worry about the greenhouse collapsing under the weight of of snow or toppling due to heavy winds (anchoring hardware is included, unlike the others).
The Mythos has two vents and a screen door for adequate circulation and keeping bugs out. The attractive aluminum frame wins out over the competitors resin frame, and what really sets the Mythos kit apart is the galvanized steel base for added support.
If you are familiar with construction projects or know some professionals who are, you may want to have a cookout or party and be sure to invite them because you are probably going to need some help putting this kit together. Afterword, you can expect many years of pleasant gardening with a Parlam’s greenhouse kit.
This kit can be readily assembled and your plants will thrive on a balcony, deck, or in a townhouse backyard. While diminutive in size, we found this unit a bit big for indoor use, but if you have the space, it could make a great addition to your indoor herb garden.
- 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 --allowing 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
- For its size and quality it is more affordable than other greenhouses
- The shelves can be unbalanced so you may need to buy cable ties to hold them into place
- The frame is a bit flimsy and do to its lightweight materials so you’ll need to place some weights in the bottom to help hold it down to prevent wind damage
A portable mini-greenhouse for the urban gardener or beginning hobby gardener.
- 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 superior to its competitors
- Assembly only takes about 15 minutes with the Velcro hook and loop system
- Easy to move from inside to outside
- The shelves are not adjustable so fitting taller plants can be an issue, but you can take out one or two shelves to make 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 from windy weather
- 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
- 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 Ogrow was an obvious choice for us due to it’s durable, compact structure, and it has a few features that seem like a no-brainer for a mini-greenhouse kit. We loved its ability to hold up to 75 lbs per shelf, the strong steel coated frame and the heartier plastic glazing. The only slight drawback to the Ogrow is its lack of ventilation, but we felt this was an easy enough fix and still well worth buying. Merely cut a couple of slits in the top of the greenhouse for ventilation.
Another reason we chose the Ogrow system 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 choose. 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
You now have the ability to make an educated decision instead of a hasty, ill advised purchase. In the end, we recommend the Parlam Mythos Hobby House. The quality of the kit is unsurpassed in its price range and your plants are sure to have all the protection they need to flourish without sacrificing light quality.
The double roof ventilation system is key for the healthy stimulation of 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 any and all questions or send replacement parts should you need them. We really feel this greenhouse kit offers you the best return on your monetary investment.
For many more great gardening tips, see our guide on 31 Ways to Make You an Organic Gardening Guru.