The 6 Best Greenhouses of 2021

Garden year-round in these warm buildings

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You can save money on this mini greenhouse, which can be installed inside or outside on a deck or patio.
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The polyethylene cover is reinforced with a layer of mesh for durability and can withstand rain and wind when installed correctly.
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This 6 x 4 foot greenhouse is just big enough for you to walk inside and tend plants on either side.
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This set of brackets allows you to build your own custom structure, including the cover material, color, and more.
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Install this durable 4 x 6 foot lean-to greenhouse against the wall of your home for stability.
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Instead of traditional plastic walls, this stylish greenhouse features rows of working glass windows.
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If you’re serious about gardening, there are numerous benefits to installing a greenhouse in your yard. By allowing you to control their climate and staying warmer than your average house, greenhouses help to extend your growing season, allowing you to start seeds earlier and keep plants producing for longer. They’re also a great place to keep tropical or subtropical plants, which require a warmer, more humid climate to thrive. 

There are many types of greenhouses to choose from, including large walk-in models that are the size of sheds (or larger), as well as small zip-open options that merely hold a few plants. To find the best option for you, think about the number and type of plants you’ll be housing, as well as how much money you’re willing to spend. 

With these factors in mind, here are the best greenhouses to buy. 

Best Budget: TOOCA 4-Tier Mini Greenhouse

TOOCA 4-Tier Mini Greenhouse

You don’t have to shell out thousands of dollars to give your plants a cozy warm space to call home—the TOOCA Mini Greenhouse is a surprisingly affordable solution that offers four shelves for all your seedlings. This miniature greenhouse can easily be installed on a deck or patio, as it’s only 63 x 19 x 27 inches, and some people even use it inside for plants that need a high-humidity environment. 

The greenhouse has a rust-resistant steel frame with four wire shelves for all your plants, and the whole thing is wrapped in a clear PVC cover with a roll-up zipper door. Each shelf can support up to 11 pounds, and the brand recommends placing heavier plants on the bottom to help stabilize the piece. Just keep in mind that this mini greenhouse isn’t very heavy—the whole thing weighs less than 10 pounds—so you may need to anchor it down if you use it outside.

Best Plastic: Quictent Upgraded 20 x 10 ft. Portable Greenhouse

Quictent Upgraded 20 x 10 ft. Portable Greenhouse

Polyethylene is a popular and affordable type of plastic, and it’s used to cover the Quictent Upgraded Portable Greenhouse. The hoop-style greenhouse is extremely big, measuring 20 feet long and 10 feet wide, and it’s more than 6.5 feet tall, as well, allowing you to easily walk inside it to tend your plants. It’s built from a heavy-duty galvanized steel frame with reinforced ground stakes and seven rows of crossbars for stability, and the whole greenhouse is covered in a green polyethylene cover that attaches to the frame using velcro straps. 

This greenhouse has large roll-up doors on both ends, as well as eight vented windows to let in fresh air. It comes with ropes and stakes for anchoring, and what’s nice is that you can easily relocate the structure if you ever want it in a different location. The plastic cover has a layer of mesh molded into it for increased durability, and when installed correctly, it can withstand rain and heavy winds.

Best Small: Palram Harmony 6 x 4 ft. Polycarbonate Greenhouse

Palram Harmony 6 x 4 ft. Polycarbonate Greenhouse

If you’re looking for a greenhouse that’s big enough to walk into but won’t take up your whole yard, the Palram Harmony is the perfect compromise with its 6 x 4 foot design. The greenhouse has a powder-coated, rust-resistant aluminum frame, and its walls and ceiling are made from virtually unbreakable polycarbonate panels. It even has a vent window that helps maintain the desired temperature and humidity levels. 

This small greenhouse stands around 7 feet tall, and it’s easy to put together thanks to a slide-n-lock assembly system. The clear panels provide 100% protection against UV rays, and they won’t yellow over time, ensuring your greenhouse always looks as good as new. The structure has built-in gutters that allow you to easily collect rainwater to hydrate your plants, and the brand offers a wide range of compatible accessories, such as shelves, lights, plant hangers, and more.

Best Kit: E-Z Frames 8 x 10 ft. Greenhouse Kit

E-Z Frames 8 x 10 ft. Greenhouse Kit

You can put your own personal style into your greenhouse with the E-Z Frames Greenhouse Kit. It comes with a unique bracket system that can be used on an 8 x 10 foot greenhouse, as well as step-by-step instructions on how to build the structure yourself. This kit only includes the necessary brackets—it doesn’t come with any lumber or siding—allowing you to customize the color, cover material, and more. 

This greenhouse kit comes with a detailed lumber cut list, and it only uses straight cuts to make the building easy for beginners. The brackets themselves are made from heavy-duty polypropylene that won’t rust or crack when exposed to elements, and they’re even made in the USA.

Best Lean-To: Ogrow Aluminum Lean-To Greenhouse

Ogrow Aluminum Lean-To Greenhouse

Standard greenhouses are generally freestanding structures, but some people prefer a “lean-to” greenhouse, which is designed to be installed up against a wall of your home. The Ogrow Lean-To Greenhouse is a stand-out option in this category thanks to its superior durability—it’s made from a sturdy rust-resistant aluminum frame with premium twin-wall polycarbonate panels. 

The 4 x 6 foot design is large enough for you to walk inside, giving you ample space to tend to your plants, and the structure has a sliding door, as well as a roof vent for proper ventilation. The side and roof panels on the greenhouse are UV-resistant, and there’s even a smartphone app to help guide you through the assembly process.

Best Design: Little Cottage Company Colonial Gable Greenhouse

Little Cottage Company Colonial Gable Greenhouse

Some people like the look of traditional greenhouses, but if you’d prefer something a bit more stylish, the Little Cottage Company Colonial Gable Greenhouse looks like a quaint woodsy cottage. The 10 x 14 foot structure features polycarbonate roofing, along with 36 working windows that make up its walls. It has a colonial-style dutch door and louver-style screened vent, and it even comes with a floor kit and shelves to line three of the inner walls. 

This splurge-worthy greenhouse is a panelized kit, meaning the walls are pre-assembled and ready to be put together. All you have to do is paint the greenhouse the color of your choosing—it’s even primed for you! Plus, it’s as durable as it is attractive, withstanding winds up to 90 MPH and supporting up to 3,100 pounds of snow. 

Final Verdict

If you are looking for a walk-in greenhouse with a small footprint, the Palram Harmony Polycarbonate Greenhouse (view at Home Depot) is a great choice. With a slide-n-lock assembly system, it is easy to install and has clear panels that provide 100% protection against UV rays. However, if you want an option for your patio, the TOCCA 4-Tier Mini Greenhouse (view at Amazon) features four shelves, a rust-resistant steel frame, and a clear PVC cover with a roll-up zipper door.

What to Look for in a Greenhouse

Size 

Greenhouses come in many different sizes, ranging from mini greenhouses that you can put on your deck to options 20 feet long that will take up a good chunk of your yard. To determine the best option for your needs, consider how you plan to use the greenhouse: If it’s just a warm, humid place to display your tropical plants, a small budget-friendly option may be the way to go. However, if you’re hoping to have a workbench and many large plants, you’re going to need to size up to a walk-in greenhouse, which start at around 6 x 4 feet. 

Material

As you compare different greenhouses, you’ll want to look at what they’re made from. Most have aluminum or steel frames, but greenhouse siding is typically made from from plastic film, polycarbonate panels, or glass. 

There are benefits to each of these materials—plastic film is the most affordable and retains heat well, but it can rip or tear and doesn’t do well in strong winds. Polycarbonate is a more durable option thanks to its shatter-resistance, and it also provides superior UV-filtering and light diffusion. However, this materially isn’t fully transparent, and you’ll also need to look for cellular polycarbonate that’s 4mm or thicker for three-season use or at least 8mm for year-round use.

Ventilation

Proper ventilation is essential for any greenhouse, as it allows you to regulate the temperature and humidity inside. On hot summer days, your greenhouse may become too warm, which often causes plants to wilt or die. For this reason, you’ll want to look for a greenhouse that includes some type of ventilation that you can control, whether it’s a window or vent. 

Weather resistance

Depending on where you live and how you plan to use your greenhouse, you may also want to look for a model that’s weather resistant. Many inexpensive plastic greenhouses don’t stand up well to heavy winds, and they’ll often collapse under the weight of snow. If you plan to leave your greenhouse up year-round, it’s best to look for a product that has a high wind-resistance and snow load capacity.

Standout features 

Temperature control

In larger greenhouses, a temperature control system can help you maintain the right level of heat for your plants. There are a few different tools that can help you regulate the temperature of your greenhouse, including horizontal air flow (HAF) fans, which help to circulate air throughout the space, as well as shade curtains, which can be closed on hot days to prevent the temperature in your greenhouse from skyrocketing. Automatic watering systems can also help to keep your plants the appropriate temperature throughout the day.

Warranty

If you’re spending a lot of money on a greenhouse, you’ll want to look into its warranty. These buildings commonly have 5- or 10-year limited warranties, during which time the manufacturer will repair or replace any defective pieces. However, most warranties mandate that you install, use, and maintain the structure based on the brand’s recommendations—so if you made changes during assembly or are using a “hobby” greenhouse to run a business, they may deny your claim. 

FAQs 

What can you grow in a greenhouse? 

One of the main benefits of greenhouses is that they extend your yearly growing season, allowing you to have plants at a time of year when they can’t be grown outdoors. This allows you to start seeds for your vegetable or flower gardens earlier in the spring and even keep plants alive and producing longer into the fall. However, you can grow virtually anything in a greenhouse, from vegetables and herbs to your favorite houseplants and flowers. It’s just a matter of maintaining a proper temperature and humidity level to help them thrive.

How do you maintain a greenhouse? 

It’s important to maintain an appropriate temperature and humidity level within your greenhouse if you want your plants to thrive, and there are a few ways to do this. You’ll definitely want a thermometer in your greenhouse to monitor the temperature—which ideally should stay around 80 to 85 degrees—and when it gets too hot, it’s important to open vents and turn on any fans to help cool the space down. You can also prop the door open or use a shade cloth to maintain the temperature in your greenhouse. Proper ventilation will also help control humidity levels, and you should take care not to overwater plants to prevent the space from getting too humid. 

There are other greenhouse maintenance tasks you’ll want to keep in mind, as well. It can be devastating if bugs infest your greenhouse, so you’ll want to stay on top of pest control, inspecting new plants to bugs before you bring them in. It’s also important to wash the interior and exterior of your greenhouse panels once a year to keep them clean—if too much grime accumulates, it can prevent sunlight from reaching your plants. 

Where should you place a greenhouse?

When installing your greenhouse, you’ll want to choose a level spot that gets at least six hours of direct sunlight per day. Keep the structure away from any trees that would cast shade over the greenhouse, and make sure the location is easily accessible—after all, you’ll probably end up visiting it every day. 

If you plan to use your greenhouse year-round, it’s best to have the ridge of the structure running east-west, as this will maximize light in the winter. However, if you’re only going to use the greenhouse in the spring and summer, align the ridge north-south, which will give it an equal amount of sun on each side and reduce the risk of overheating on hot days.

Why Trust The Spruce?

This article was written by Camryn Rabideau, a freelance writer and avid home gardener. Growing up, her mother was a florist, so she spent a lot of time in their family's large polycarbonate greenhouse, and today, she has a small hoophouse of her own where she starts seeds each spring.

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