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Growing Year-Round: Setting Up Your Backyard Greenhouse

If you’re an even halfway serious home gardener, you’ve no doubt thought of building or buying a backyard greenhouse. In addition to giving vegetable and flower seedlings and ornamental plants an early start on spring, a backyard greenhouse can serve as a relaxing retreat.

Your greenhouse, whether existing or imagined, may be just some clear plastic sheeting stretched across a frame. Or, maybe, it’s an elaborately built centerpiece of your backyard. However it’s built or imagined, some basic rules exist for properly setting up a backyard greenhouse.

Read on to learn how to make your backyard greenhouse a truly functional and inviting place within your home landscape.

Backyard greenhouse with plants

Basics of Setting up a Backyard Greenhouse

Whether you have or want a utilitarian backyard greenhouse or a significant addition to your home landscape, one simple thing will be key to your success. Above all else, a greenhouse should be located where it will receive maximum exposure to sunlight for as many days as possible.

No matter where you’re located, the optimal location for a backyard greenhouse is on your lot’s southern or southeastern side. Provided it’s not unduly shaded, a southern or southeastern location gives your greenhouse the fullest exposure to the sun on its daily east-west track across the sky.

That sun exposure is particularly important during the fall and winter, when your greenhouse will be full of plants and seedlings awaiting transplantation outdoors. However, if you don’t have a suitable southern or southeastern exposure, you need not necessarily give up.

If you have space on the eastern side of your tract, or even the western or southwestern corners, you can still have a successful greenhouse. And if there is no other choice, you can locate a greenhouse on the north side of your lot, but your results may not be inspiring.

Greenhouse Size

As you consider where to locate your backyard greenhouse on your lot, you’ll also need to decide what size you’ll need or want it to be. The best rule to follow here is to make it larger than you think you want, particularly if you’ll be working or relaxing inside it.

For example, an 8-foot by 8-foot backyard greenhouse might have reasonably adequate space for plants and some shelving. But working might feel a little constrained, particularly with more than one person inside. And it likely won’t have room for watering cans, gardening tools, and other needed items.

You’ll also want to consider how tall you’ll want the walls of your backyard greenhouse. For most purposes, a 5-foot wall will be adequate. However, if you’re growing tall plants or plan to grow plants on shelving installed in the greenhouse, plan for a 6- or 7-foot wall.

Finally, the roof slope of your greenhouse should be around 30 degrees. If your walls are 5 feet tall, with a 27-degree slant, the peak of your roof will be 9.5 feet above the ground.

Greenhouse with tomato plants

Obviously, if you’ll use your backyard greenhouse as a home office, or as living and gathering space, you’ll need additional floor space to accommodate furnishings. As a guide, consider that the average home office measures 10 by 15 feet, and an average family room measures 16 by 24 feet.

Certainly, some of the space dedicated to greenhouse plants can be incorporated into living space or office space. Still, a multi-function greenhouse will need to be significantly larger than a structure dedicated simply to housing seedlings, plants, and gardening gear.

As a final note, no matter what size your greenhouse will be, be sure that its footprint won’t interfere with access to underground utilities.

Greenhouse Foundation

If you’re planning a utilitarian backyard greenhouse for potting plants, growing seedlings, and storing tools, you may not need to worry too much about a foundation. It may be enough to simply tamp down the dirt at your chosen site, and maybe cover it with a layer of gravel or river rock.

If you do opt for this approach, be sure to install a plastic ground cover over the tamped-down soil. Doing so will prevent weeds and other vegetation from growing through the gravel or river rock.

However, if you’d like your backyard greenhouse to appear as an integrated part of your home landscape, you’ll almost certainly need a more elaborate foundation. In addition to its more finished look, a sturdy and level foundation will ensure your greenhouse windows don’t pop out, and its doors don’t stick.

Installing paving slabs atop a leveled greenhouse site is an easy way to provide a solid greenhouse foundation. Or, you can lay pressure-treated wood into the soil and attach the greenhouse to it. But the best foundation for your greenhouse will be a poured concrete slab.

A concrete slab is also the priciest foundation option, and it will require some work to ensure proper drainage. Otherwise, standing water, from watering plants or cleaning the greenhouse, can create unpleasant odors and other problems.

Concrete will, however, be the most sturdy and durable foundation for your backyard greenhouse.

Greenhouse Flooring

If you’re going to use part of your greenhouse as an office or living space, chances are you won’t want gravel, river rock, or concrete flooring. For spaces in your greenhouse that won’t get wet or overly dirty, options like brick or vinyl tile are worth considering.

And even in the working area of your greenhouse, you may want something to cover your concrete floor. In that case, you should consider rubber floor matting. In addition to giving a more decorative touch to your greenhouse, rubber flooring is more comfortable to stand and walk on than concrete.

Controlling Humidity and Temperature in a Backyard Greenhouse

The indispensable key to a successful backyard greenhouse is maintaining a balance between temperature and humidity. Plants like a moist environment — but not so moist that disease becomes a real possibility.

Humidity Control

Ideally, the humidity in your greenhouse should be maintained at somewhere between 40% and 60%. Keeping track of the humidity in your greenhouse is as simple as installing an analog hygrometer and periodically checking the numbers.

Greenhouse with open windows

Ensuring adequate air circulation is important for avoiding high humidity in your greenhouse. One way to do that is to have greenhouse windows that can be opened. If you notice condensation forming, open windows to create some cross-ventilation.

If your greenhouse doesn’t have operable windows, simply open the greenhouse door to promote air circulation and reduce humidity.

Temperature Control

The ideal greenhouse temperature for most plants is between 80 and 85 degrees. Any temperatures outside that range, whether low or high, create the potential for mold, mildew, or pest infestation.

Just as with humidity, having windows that can open or other venting options can help control greenhouse temperatures. Similarly, fans can also help. If your greenhouse doesn’t have electrical service, you can run an extension cord from your house to a fan placed inside the greenhouse.

An interesting passive option for controlling the temperature in your greenhouse is to use buckets filled with water. In the summer, place jugs of water in shaded areas of the greenhouse, and they’ll absorb heat from the air.

In winter, place water jugs in sunny areas of the greenhouse. Cover them with black plastic to absorb heat and disseminate it into the greenhouse.

Arranging Plant Workspace in a Backyard Greenhouse

Once you have a backyard greenhouse, you’ll need to arrange it for ease and comfort as you tend to your plants. First, you’ll want to set up benches along the two long walls of the greenhouse to hold your plants.

Whether you buy or build your workbenches, make sure they’re at a comfortable working height and are less than three feet wide. Any wider, and you won’t be able to comfortably reach plants and tools. And, of course, three feet is a considerable amount of space to occupy in a smaller greenhouse.

As another tip, leave at least 19 inches of space between the workbenches on either side of the greenhouse. That spacing will ensure you can access the entire greenhouse for comfortable working.

Potting Bench

A potting bench is one of the work areas you’ll need in your backyard greenhouse. That’s where you’ll move growing seedlings into larger pots, and likely also where you’ll store fertilizer, potting soil, and smaller gardening tools.

A location at or near the front door of your greenhouse will work well as a place for your potting bench. However, if a spot in your greenhouse gets more than occasional shade, consider locating your potting bench there. That way, sunnier spaces will be available for your growing plants.

Tool Storage

While you may store your larger gardening tools — shovels, rakes, etc. — in your garage, your greenhouse will be a better place to keep them. To do that, you’ll need some type of storage cabinet, and the best place for that cabinet will be adjacent to your potting bench.


Another consideration when setting up your backyard greenhouse is shelving. Adequate shelf space is particularly important if you’re growing large flats of plants from seed. Place seedlings on the topmost shelves, so they can take advantage of the heat in the greenhouse as it rises from floor to ceiling.

If space is at a premium in your greenhouse, consider installing shelving on the back sides of your workbenches. Those shelves can be a perfect spot for seedlings and plants that don’t require a lot of direct sunlight.

More Greenhouse-Arranging Tips

As you’re planning your greenhouse layout, consider buying or building workbenches equipped with wheels. Wheeled workbenches can make it easier to move plants as needed as sunlight and shade conditions change during the year.

Also, if you have potted plants as part of your exterior home landscape, allocate some space in your backyard greenhouse for holding them during winter. When not in use for over-wintering, that space can be used for other plants, particularly tall or wide specimens.

Using a Backyard Greenhouse as Living Space

If you’re planning to use part of your greenhouse space as living space, what you’ll be creating is known formally as a conservatory. If that’s the functionality you’re going for, you’ll want to install a tile, brick, or other type of floor to clearly delineate the living space.

Backyard greenhouse with chairs and table

That doesn’t mean, though, that the living space has to be completely free of plants. On the contrary, incorporating greenhouse specimens can help create an elegant environment. Keep in mind that your aim should be to create a stylish outdoorsy space with the advantage of protection from the elements.

In addition to comfortable chairs and maybe even a couch, consider including a table and chairs in your greenhouse for outdoor dining. Other items to consider including in your greenhouse living space are rugs and fancy lighting fixtures — battery-powered if the greenhouse doesn’t have electrical service.

If your greenhouse is visible to your neighbors, you should install drapes or blinds to ensure privacy when the living space is in use.

Setting up Your Backyard Greenhouse Frequently Asked Questions

Now that you’ve read about the basic aspects of setting up your backyard greenhouse, some additional questions may have occurred. Read on for insights on a few of the issues regarding your backyard greenhouse that may still be on your mind.

What are some of the best recommendations for greenhouse kits?

If you’ve decided you want a greenhouse, but know you don’t want the hassle of building one yourself, or contracting for the project, don’t despair. There are plenty of greenhouse kits available that can help you expand your gardening ventures.

Be aware, though, that some greenhouse kits will be little more than a clear material stretched across a frame. If your greenhouse is going to be a feature of your backyard landscape, you’ll certainly want a more substantial structure.

Among your best choices for functional but attractive greenhouse kits is the Palram Canopia, a 6-foot by 8-foot aluminum structure sheathed in clear polycarbonate. If you’re looking for a larger greenhouse kit, consider the VEIKOU greenhouse, measuring 8 feet by 14 feet.

Is using old windows to build a greenhouse a reasonable do-it-yourself project?

Look at almost any do-it-yourself gardening or home improvement website, and you’ll see information and/or plans for constructing a greenhouse from salvaged windows.

Obtained largely from flea markets or architectural salvage stores, the salvaged windows are laid out in a pattern fitting the size of each greenhouse wall.

It’s an interesting look for a greenhouse, but there are some construction challenges. Framing the walls is particularly difficult because the windows will very rarely fit between standard wood-frame construction.

In framing the walls for a salvaged-window greenhouse, you’ll have to insert wood or other material between mismatched windows to bring the walls to your desired dimensions. Similarly, framing doorways and ventilation around different-sized windows can be difficult.

While it’s certainly possible to build a salvaged-window greenhouse as a do-it-yourself project, you’ll need to be honest about the level of your DIY skills. If there’s any doubt, get a contractor to do the work, or take your greenhouse plan in a different direction.

Is it possible to have too many plants in a greenhouse?

By definition, a greenhouse offers limited space for growing plants or starting seedlings for later transplanting into your yard. But as long as you follow spacing directions for plants placed directly into the ground or in raised beds, you should be fine.

A variety of plants in a greenhouse

However, spacing is not the only measure for determining whether you have too many plants in your greenhouse. If you have so many plants that you’re spending more time than you can afford tending to them, you clearly have overloaded your greenhouse.

Wrapping up Setting up Your Backyard Greenhouse

Whether you’re interested in cultivating vegetables, herbs, flowers, or decorative plants, a backyard greenhouse is a great way to extend your growing season. So, now that you’ve learned how to set up a backyard greenhouse, you‘re ready to start enjoying gardening for many more days of the year.

For more advice on maximizing the enjoyment of your home landscape, check out these other posts on backyard living at Minneopa Orchards.