Such limitless opportunities can make it easy to want to rush out and buy the first good-looking greenhouse you see, but it is important to put research and thought into what kind of greenhouse best suits your needs. Greenhouses can be small enough to be kept on your porch or large enough to fill your backyard. There are different materials used for the structure and the siding, and different mechanisms for temperature control. With a plethora of options, sizes, and structure shapes to sort through, choosing a greenhouse requires careful planning to ensure you get the best experience possible. We’ve spoken with gardening expert Lindsay Pangborn to learn the ins and outs of greenhouses. “For home gardeners, the addition of a greenhouse to their growing arsenal can be game-changing,” says Pangborn. So if you’re ready to take your gardening to the next level, use this guide, to pick out your greenhouse with confidence.
Before Buying a New Greenhouse
The first thing to consider is how exactly you want to use your greenhouse. That large, beautifully constructed, glass cottage may be tempting, but it may not be worth it if you only plan to start a few seeds or house a couple of plants. In this case, a small, portable greenhouse may be best. If you simply wish to start seedlings early, keeping plants indoors under grow lights may be all you need. On the other hand, if you plan to supply your garden with plenty of seedlings and hope to harvest well into the fall, then a large greenhouse in your backyard is a better option. Pangborn offers this advice: “Greenhouses, or even just cold-frame houses, can extend the growing season both ways, meaning it’s possible to begin growing earlier in the spring, prolonging later into the fall. This has many benefits outside of a longer enjoyment period, such as the ability to grow crops that take longer to mature and to increase harvest amounts.” Thinking about how you wish to use the greenhouse, what kind of plants you want to grow, and whether or not you want to grow year-round will significantly simplify the decision-making process.
Buying Considerations for Greenhouses
Space
Greenhouses come in a large array of sizes. There are small, portable greenhouses that fit on your porch or even indoors, large, sprawling greenhouses that take up a big portion of your backyard, and every size in between. The size of both the greenhouse and your available space are both important factors to consider. Which size you choose will depend on how many plants you want to fit inside the greenhouse and how much space you have on your property to accommodate the greenhouse.
Materials
Both the structure and the siding of greenhouses are available in multiple different materials. Structures are often made out of wood, aluminum, steel, or PVC. Greenhouse siding is usually made from plastic, glass, fiberglass, polycarbonate, or polyethylene. The material chosen for one aspect affects the other. For example, PVC greenhouses often support plastic or polyethylene sides, while steel or wood usually supports glass or polycarbonate panes.
Shape
Greenhouses are often thought of as small, shed-like structures. However, greenhouses come in many shapes, including small shelving units, lean-tos, and long, round-topped buildings. The shape you choose again comes back again to the intended use. Compact shelf-style units are great for small areas or a small number of plants, lean-tos are better for tight spaces or the convenience of having the greenhouse close to the house, and large, round structures are ideal for big gardens or farms.
Flooring and Foundations
Many greenhouse structures and kits do not require a full cement foundation, though some might. It is important to take note of this when choosing a greenhouse. Even if the greenhouse does not require a full foundation, some kind of flooring is often desirable. Options include pavers, pea gravel, or wood chip pathways.
Features For Temperature Control
Controlling the temperature and humidity inside the greenhouse is extremely important, since creating warm temperatures ideal for growing is the whole purpose of a greenhouse. Mechanisms used for temperature control include electric, gas, propane, and natural gas heating elements. These are critical if you plan to garden through the winter. Windows, fans, or shade curtains are needed during the hot summer day to help keep the greenhouse from getting overheated.
Additional Features
Many greenhouse structures or kits only come with the bare bones of the greenhouse: the framing and the siding. Shelvings units for seedlings, work tables, and benches usually need to be purchased separately. There is usually some form of temperature regulation feature, such as windows, but additional features may need to be purchased as well, such as heating units or automatic waterers. These additional costs are important to factor in when deciding on a greenhouse.
Types of Greenhouse Styles
There are two main categories of greenhouses: attached and freestanding. As suggested by the names, attached greenhouses are attached to another building, while freestanding greenhouses stand apart from other structures. Within these two categories, there are a number of styles to consider
Conventional or Post and Rafter
This style is a very popular freestanding structure and is often the most thought of when referring to greenhouses. Post and rafter structures are the iconic shed-shaped greenhouses built like miniature houses. These structures have tall growing spaces, even next to the walls, and are the sturdiest structures. This allows these structures to support heavy glass panes. However, because of these features, post and rafter greenhouses need footings or a sturdy foundation to support their top-heavy weight. Post and rafter style greenhouses are ideal for people serious about growing large quantities of plants. The need for footings makes them a more permanent structure in your yard.
Lean-To
Lean-tos are attached greenhouses that lean on another structure. These are built on the south-facing wall of houses or sheds, giving these greenhouses extra support and protection from the elements. However, the structure they are built onto may create unwanted shade. Lean-tos are more compact in design, and therefore have less growing space than other styles. Because of their compact design, lean-to greenhouses are perfect for small yards. And since one whole side is composed of an already existing structure, they require fewer materials. Lean-to greenhouses are great for those with limited space who still wish to grow a decent amount of plants.
A-Frame
A-frame greenhouses are just like A-frame houses: the roof extends to the ground, creating a triangle shape. These freestanding greenhouses are great for those looking to save money on building materials since fewer materials are needed to create this structure. They are also quite easy to construct. However, their tight corners and short ceiling heights near the edges limit growing space and can be hard to air out. These structures are perfect for those looking for an easy setup with few materials. Large A-frame greenhouses offer plenty of space for growing, though the sides can get tight. Therefore, they are not ideal for large crops or particularly tall people.
Uneven-Span
Uneven-span greenhouses are exactly what you would imagine: a greenhouse with an uneven roof. This lopsided design makes greenhouse construction possible on hilly terrain or in areas where the greenhouse must be constructed to receive the greatest amount of sun. These structures are great for areas where other structures may not be accommodated. However, their unique shape can create tight spaces hard to work in and hard to air out. Uneven-span greenhouses are perfect for someone trying to grow in hilly, uneven terrain where other structures cannot be built. They also can be angled to take full advantage of the sunlight in areas where the sun’s angle may be extreme.
Gothic Arch
These greenhouses mirror the iconic gothic window shape, which is where its name came from. The side frame is rounded to meet at a point at the apex, creating this unique shape. Because of this construction, these freestanding greenhouses are quite easy to build and use fewer materials than other structures, such as a post and rafter. Its rounded sides allow rain and snow to easily slide off. Gothic arch greenhouses are ideal for those looking for ample room inside, easy construction, and a unique shape.
Quonset or Hoop House
Quonset or hoop house greenhouses are comprised of large, rounded, hoop-like frames, creating a structure similar to a tunnel. Like gothic arch greenhouses, the Quonset or hoop house style is easy to build and sheds rain and snow with ease. These are often constructed from aluminum or PVC frames and plastic sides, making them a more inexpensive option. As a downside, its curved sides mean there is less growing room near the edges. This makes shorter crops ideal for Quonset-style greenhouses. Hoop houses make ideal lower-cost greenhouses. They are easy to construct, making them perfect for anyone looking to put up a greenhouse without the work associated with more shed-like greenhouses.
Portable or Mini Greenhouse
Unlike the structures mentioned above, a mini greenhouse is more of a small shelving unit. These are usually made of plastic and can be small enough to fit indoors or on a small porch. These greenhouses are perfect for anyone who wishes to grow only a few plants or only has the space for a small unit. These are great for balconies or patios, and are popular for gardeners living in condos or apartments. Gardening expert Pangborn points out the flexibility of portable or mini greenhouses: “Consider whether you want a permanent structure or something that’s able to be packed away for the summer or moved to different areas of your garden.”
Cost
Because there is such a large array of sizes and materials, greenhouse costs can differ widely. Materials and design play a large factor in the cost. For example, a conventional greenhouse made of wood, steel, and glass can be anywhere from $3,000 to $10,000 or more. On the other hand, small aluminum and polycarbonate greenhouse kits are commonly around $200 to $600. Larger kits may be $1,000 to $5,000. And mini, portable greenhouses are usually anywhere from $40 to $100. Many of these options only include the framing and siding, which means interior shelving, benches, workspaces, and temperature control units are all extra expenses. This is something to keep in mind when choosing the size and shape of the greenhouse, as larger greenhouses may require more interior items and temperature control mechanisms. A good time to buy a greenhouse is during the winter months, such as December, January, and February. This may seem like an odd time, but this has multiple advantages. During this time, the gardens are sleeping and you have time to plan out construction, building, and planting without the mad rush to do it all at once in the spring. This way, you have everything in order and ready to go when you are ready to plant. This is also the time many companies run winter sales. Because gardening isn’t on many people’s minds, garden supplies are often on sale.
How to Choose a Greenhouse
Such a large array of greenhouse options doesn’t have to be intimidating. By considering a few things, you can quickly and easily narrow down your choices and find the greenhouse that suits your needs and wants.
How big is your yard?
The amount of space you have available for your greenhouse will greatly influence what type of greenhouse you purchase. If you have a large yard, you can easily accommodate a large, freestanding greenhouse. If your yard is on the smaller end, you may wish to purchase a lean-to to maximize space. Or if you live in an apartment, you may need a mini or portable greenhouse that fits on your patio. The layout and shape of your yard is also something to consider. An uneven, hilly space may be better suited for an uneven-span greenhouse.
How much do you want to grow?
Once you’ve established the amount of space you have available to accommodate the greenhouse, you should ask yourself just how much you want to grow. Just because you can fit a large greenhouse on your property doesn’t mean that’s the right choice. If you wish to grow a few plants, a mini greenhouse or small lean-to might be better suited to your situation.
What kinds of plants do you want to grow?
Some greenhouses, like the a-frame and the hoop house, have narrow edges that cannot accommodate tall plants. However, plants that are low to medium in height would be just fine, making these perfectly acceptable options.
How much are you willing to spend?
Greenhouses made from hefty materials, such as wood, steel, and glass, will be more expensive than a greenhouse constructed from PVC or plastic. And the heavier the material, the more likely the structure will need some kind of support, such as footings or foundations, which will increase the cost.
Where to Shop
There are many places you can buy greenhouses, including online, from garden or home centers, or even specific greenhouse manufacturers. Wherever you buy a greenhouse, be sure you get the details of any warranties, return policies, or delivery options for large structures. Once received, check over the components to ensure they are all in good shape and that all the pieces are included.
Buying In-Store
Greenhouses can be bought from big-box home or garden centers, like Home Depot, Lowe’s, or Tractor Supply Company, or greenhouse manufacturing companies. When shopping in-store, take a look at all the options available, making note of the materials used, the cost, and any warranties or guarantees. Ask a salesperson whether there are any provisions for delivery for large items or if the store itself has any warranties.
