DIY Backyard Greenhouse
Backyard | Gardening & Landscaping | Outdoor Projects

Building a Backyard Greenhouse: 9 Things To Know Before Starting

If you are planning on building a backyard greenhouse, make sure to read these nine important tips before starting your greenhouse endeavor.

With spring just around the corner, getting a hold of some fresh seasonal produce is always on our minds. So, we thought why not try growing some ourselves?

Planning what seeds to get, when to plant them, and waiting to see the results are the best parts of growing your own fruits, veggies, and spices. But dealing with the finicky weather? That’s where problems can start to arise, and also why building a backyard greenhouse makes so much sense! 

It’s completely DIY-able with a host of benefits like year-round gardening, endless possibilities of what to grow, the best frost protection for plants, and more.

Be it building your own terrarium or putting together a standalone greenhouse with old windows, if you ask us, we’ll say anything can be DIY-ed!

You’ll find tons of inspiration on the internet and free greenhouse plans to help you get started!

Polythene, mesh, or recycled windows, with a little planning and effort, you can have your own DIY backyard greenhouse. But before you start drawing out your plans, here are 9 things you need to know.

DIY Backyard Greenhouse

Consider What You Want to Grow

The coolest part about building and owning a greenhouse is that it allows you to grow almost anything you’d like, even new kinds of plants or vegetables that are otherwise not suited to the weather outside.

Tropical plants

Tropical plants usually need a warm and humid climate to grow. While the basic necessities of soil and fertilizer are the same, you will need to regulate your indoor temperature to suit their needs. 

From cacti to orchids and venus flytraps, there are loads of tropical plants that you can reserve a section of your greenhouse for.

Ornamentals

Ornamental plants, like their name suggests, are grown for the purpose of display. Grouped either as sun-loving or shade-loving, some regrow every spring while others grow only for one season. 

While populating and building a backyard greenhouse, you can choose anything from pretty geraniums to delicate petunias. They’re the perfect mood-lifters on a rainy day!

Cool-season crops

Cool-season crops include yummy and nutritious plants like lettuce, broccoli, and kale, and you can grow them all in your greenhouse. Grow these in cold frame greenhouses in which they will be able to tolerate cold nights.

You’ll find that heating isn’t necessary unless you live in extremely cold climates (below 32°F).

Warm-season crops

Tomatoes, cucumbers, peppers, you name it! You can grow them all in your greenhouse. These crops thrive in temperatures that range between 55° and 85°F. 

Once you get the temperature just right, you’ll have your table full of beautiful veggies that can be enjoyed year-round!

Greenhouse Options, Budget, & Sizing

Below are quite a few different options for types of greenhouses and the corresponding budget and sizing.

Greenhouse Kits

Greenhouse kits can really make your work easier, but depending on what you’re going for, can either be affordable or expensive. They can run from around $100 (4’x4’) to upwards of $10,000. 

Kits detail how to set up your greenhouse and provide the materials needed, but if you’re looking to customize, then keep in mind that your costs will increase. As far as standard greenhouses go, however, a kit is definitely a good option. 

Recycled materials 

If you’re wondering how to build a greenhouse for less, try using recycled materials.

PVC pipes for the frames, fish tanks for terrariums, and old windows significantly decrease the cost of building a backyard greenhouse. 

These options are sustainable and create a lot of room to let your imagination run wild. Compostable hotbeds are the best option for heating and conserving energy during the winters.

With this, you can be done with your greenhouse for under $1000, with the smaller ones possibly even costing as little as $100! 

Small-scale DIY

You can save big with a small-scale DIY

Terrariums and window greenhouses are definitely the best.

With goldfish bowls available online and different options for extending your window sill, you won’t have to worry about expensive additional heating and light. 

If you’re thinking of using recycled items and starting small, then your DIY greenhouse can be ready for as little as $10! This undoubtedly makes for a huge save and an approachable way to start exploring your green thumb.

Large-scale DIY

Large-scale DIYs need a lot of planning which involves choosing your materials and allotting your budget accordingly. 

Consider starting out with a beautiful, small greenhouse for vegetables as your first project!

While general dimensions are usually 10’ x 14’ and above, yours can be any size you like. Just make sure to map out the space available to you. 

Several other large DIY greenhouses use glass with wooden frames, even giving you the opportunity to repurpose old windows!

Whether it is a lean-to or a standalone structure, with a little brainstorming, large-scale DIYs are no problem to build. While budgeting and sizing, make sure to maximize on low-cost options that help in creating your dream garden.

For winter crops especially, inexpensive options are the way to proceed. You’ll have a great harvest at a fraction of the cost!

DIY Backyard Greenhouse

Type of Greenhouse

The type of greenhouse that you choose to build will depend on the space you’ve got available as well as what you’d like to plant. 

Attached Lean-to

This type of greenhouse has one or more sides that lean on an already existing building. It is an enclosed space that is not usually that big but covers the length of one side of your house.

You’d typically be able to grow single or double-row plants in this greenhouse. It’s a great way to grow batches of seasonal veggies, regardless of the outside climate.

Standalone

Standalone greenhouses are not attached to any structure but located separately in your backyard. When building a backyard standalone greenhouse, it makes sense to place it close to your outdoor garden space. 

This type of greenhouse comes with many options and styles. It can be window-framed, wooden and domed, or furrowed – it’s your pick!

Window greenhouse

Window or glass greenhouses are arguably the best ways to conserve heat and sunlight.

In these greenhouses, the entire structure is made of glass. This helps in creating even temperatures and preventing your plants from contracting diseases.

You can choose to build a window greenhouse as a standalone structure, or attached to your home. 

Tabletop greenhouse

Tabletop greenhouses are the cutest new thing on the block and perfect if you have limited space.

These tiny greenhouses can be kept in a corner of your home, on coffee tables, or on the countertop. They’re cheap, handy, and so adorable!

Grow beautiful succulents, herbs, or microgreens – the choice is all yours.

Terrariums

These popular little space savers are in a way a kind of tabletop greenhouse and look beautiful in even the tightest of spots.

You can convert any glass container into a terrarium, whether it’s cute goldfish bowls or mason jars.

These are fully or partially covered and allow heat and light to enter. They’re great at moisture-locking so that your plants remain healthy.

Window-mounted

If you don’t have the space for a whole new structure, then this type of greenhouse is perfect for your home.

It’s built as an extension to your window and is attached to the sill. 

We recommend building them as extensions to your kitchen windows for easy access to herbs and vegetables, but really, you can build yours anywhere you like.

Materials Needed for a Backyard Greenhouse

Greenhouse Frame

There are quite a few different materials you can use for your backyard greenhouse.

DIY Backyard Greenhouse
  • Wood

Most greenhouses use pine wood, which is inexpensive and strong, but timber is also a good option.

While pondering how to build a greenhouse out of wood, we highly suggest considering wood that is resistant to moisture and rot. This is because the air in a greenhouse is usually damp. 

Chemically treated wood also does the job. 

  • Aluminum

Aluminum is moisture-resistant, does not rot, or break! It provides a good shape and form to your greenhouse.

All it takes is some doubled-up heavy gauge pieces to reinforce the frame and you’ll be planting seasonal veggies and tropical flowers in your ideal greenhouse in no time!

  • Steel

Strong, inexpensive, and easily available, steel is definitely a popular option for greenhouses. It’s also thin which minimizes the risk of casting large shadows on your plants. 

  • Old windows

Building your own greenhouse is a great way to repurpose some old windows. First, pair the windows and plan the structure of your greenhouse. Then, just join, reinforce, and paint! It’s an amazingly cost-effective method, with almost the entire structure being made from reusable materials. 

Walls

When building your backyard greenhouse, you have a few options when it comes to walls.

  • Fiberglass

Fiberglass is a popular greenhouse covering material due to its ability to diffuse light and provide good insulation. While it is a little difficult to clean, it’s also inexpensive, making it a good alternative to use for tiny greenhouses.

  • Plastic sheeting

Greenhouse plastic sheeting doesn’t tear easily and is designed to withstand all weather conditions. It’s also less expensive than a large frame of glass and can perfectly match the shape and size of any frame. 

  • Old windows and glass

Glass is the highest-quality option for your greenhouse. It’s the best way to ensure your plants get sunshine and maintain the warm temperature inside. Old glass windows are a great option as they have the advantage of being reusable, as well as coming with their own frames.

Walls made from old windows are the same as glass walls, just more cost-effective!

  • Plastic Panels

Polycarbonate sheets are a common greenhouse alternative for glass. They’re light, durable, and retain heat. However, it should be noted that this material is a little prone to condensation which leads to them needing to be cleaned frequently. 

You can buy them online or contact your nearest hardware store.

Flooring

Just as you have options for the frame and the walls, you also have options for the floor of your greenhouse.

  • Dirt

Put simply, this is the singular most simple option for flooring. Dirt is easily available, has minimum hassles associated with upkeep, is dirt-cheap (quite literally), and does wonders at locking moisture in place.

  • Gravel

Gravel is a budget-friendly option that is also sturdy. It’s easy to maintain, reduces the risk of rodents, and prevents erosion. 

  • Stone

Stone floors are a permanent fixture in a greenhouse. They ensure that heat is conserved, and that the necessary environmental controls are maintained. However, this arrangement requires additional surface drain removal systems so that water can drain out easily. 

  • Recycled Materials

If you’re looking for eco-friendly alternatives for your greenhouse floor, then simply recycle what you already have. A great option is to recycle old planks or pieces of wood. Old bricks work well too.

Location

Your greenhouse should ideally be located in an area with ample sunshine and natural daylight. You definitely want to avoid building a greenhouse in the shade, or somewhere with harsh winds and frost pockets.

If you’re planning on growing plants throughout the year, consider building a roof that runs east-west. This maximizes the light available during the winter months.

Even for attached greenhouses, you’ll want to consider what part of your house gets a good amount of sun. Avoid places that are too damp or wet, as this can become a disadvantage in colder weather. 

Basically, good natural light is a must while planning the location of your greenhouse. 

DIY Backyard Greenhouse

Permits

While it’s possible that you need a permit to build a backyard greenhouse, it really depends on the permitting procedures of your location. Some places equate building a greenhouse to building a shed, which removes the issue of needing a permit altogether. 

To err on the side of caution, you’ll need to get in touch with local building authorities before you get started. Some municipalities may require that you fill in a few forms before constructing a permanent structure.

Check out the zoning and building regulations applicable in your area, or check with the planning department for what rules apply.. 

Heating and Lighting

Heating 

The temperature in a greenhouse depends entirely on the kind of plants you plan to grow. Often, a greenhouse will have day temperatures of 70° to 80° F, with lower night temperatures.

Ultimately what you want for your greenhouse are temperatures that can be regulated. A good heating system is extremely important. Natural gas, LP gas, and wood are options worth considering. 

In colder climates, consider building hotbeds from compostable materials for better heating. 

Lighting

Supplemental lighting may need to be incorporated if your greenhouse does not receive sufficient sunlight. 

Consider installing high-pressure sodium fixtures or LED fixtures to help in the growing stage. LED fixtures are good for energy conservation and also have a long lifespan, making them an affordable option in the long run. 

Accessibility 

After planning the heating and lighting fixtures, you’ll need to consider size and space.

While constructing your greenhouse, remember to measure out space for walking in and out, and working inside. 

With attached structures, you can install a door that is accessible from the inside. Consider planning for one row of crops and constructing ledges for tinier plants. This will create plenty of space to move and work freely inside your greenhouse.

Window greenhouses are naturally accessible, and a small opening is enough.

With standalone outdoor greenhouses, plan for doors and install similar shelves as the attached ones. 

Refer to customized plans for better results!

Utilities

You definitely want to consider the utilities needed – such as water and electricity – when building a backyard greenhouse.

Water

There are different watering methods you can choose between to maintain your backyard greenhouse. 

Fancy capillary mats, drip irrigation, or misting systems are usually on the higher end, with some costing $500 or more. However, for a small backyard greenhouse, nothing beats watering plants by hand. It’s the quickest and most accessible option.

Click here for some great DIY alternatives that are both effective and cheap!

Electricity

A greenhouse will need an electrical connection to ensure overhead lighting and proper artificial heating.

We would recommend consulting an electrician if you want to install underground cables that supply electricity from your house to your greenhouse. 

For simpler, low-maintenance greenhouses or indoor greenhouses, however, electricity is not a major factor. The existing climate is usually enough to ensure plant growth.

Frequently Asked Questions

Is it cheaper to build your own greenhouse?

Yes. It is usually cheaper to build your own greenhouse, but it depends entirely on the style, materials used, and if you’re using a kit or not.

If you choose to DIY your greenhouse, you can have it made for under $100!

However, professionally made ones can cost anywhere between $2,000 and $10,000, and sometimes even more. 

How much does it cost to build a backyard greenhouse?

In regard to building a backyard greenhouse, standard mid-sized greenhouses cost around $25 per square foot when built professionally. Depending on your materials, yours can come down to much less. 

Wood and steel frames are great ways to minimize costs, and reusing old windows really does make a difference.

Is it cheaper to build a greenhouse or buy a kit?

Kits range from $100 to $10,000 and buying a heavily customized kit may cost much more than building your own greenhouse. 

Usually, building your own is a cheaper alternative and makes the most of already available materials. 

Cheap kits with no customizations are also an inexpensive option that can be explored, but the downside is that this option offers little room to get creative.

What will hold the heat inside the greenhouse?

Windows are perfect for holding the heat inside. Hotbeds, ventilators, and bubble wrap are also some great ways to trap heat inside the greenhouse. 

Where do you put the greenhouse in relation to the sunlight?

You’ll need to build your greenhouse in an area of your backyard that has ample sunlight. Depending on your space and style, it’s ideal if lean-to greenhouses are built south-facing.

Ridges of the roof running east-west are also a good way to increase sunlight absorption.

Where could I find plans for building my own greenhouse?

The Spruce and Free Woodworking Plan.com have some great free greenhouse plans that are extremely helpful.

Also, check out these amazing green-house projects by Ana White that you can recreate at home.

Does a greenhouse need a clear roof?

No, greenhouses don’t always need a clear roof. The roof you choose will depend on the plants you want to grow.

Some plants, like tropical plants and succulents, require a lot of sunlight, which is why a clear roof is preferred. 

Opaque roofs are great for diffused sunlight and better environmental controls. 

And if you have the option to install lighting fixtures, it doesn’t really matter what kind of roof you have.

Is plexiglass for a greenhouse? 

You can absolutely use plexiglass for a greenhouse. 

Plexiglass is much more sturdy than glass, conducts heat just as well, and offers protection from harsh sunlight. 

I hope you found this article on building a backyard greenhouse helpful!

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