Easy Steps On How To Build A Greenhouse On Your Own

Wouldn’t it be great to grow delicious, juicy tomatoes all year long, and pick cheerful, bright flowers even on dreary days? You can have these and a lot more if you learn how to build a greenhouse on your own.

A young man in a beautiful small greenhouse, tending his plants

Building a greenhouse is easy, affordable, and will provide you and your family with fresh, tasty and nutritious food. In this article, we will show you how you can do all that without being a professional. Follow the steps below and you’ll be enjoying your new greenhouse in no time! Without further ado, let’s get started!

Choosing the right location

First things first, you need to know where you’re going to place your greenhouse. And don’t forget that there are certain things that you should keep in mind. Have a look!

1. Exposure to Sun

For a successful greenhouse, you need good and consistent sunlight. Therefore, depending on your location, you should select a north or south facing area.

A lean-to greenhouse attached to a brick wall, with brick-built white glasshouse

Make sure that all the structures are to the north of your greenhouse. A lean-to is one of the main structures and you should choose a south wall for it

Even though all-day sun exposure is the ideal option, an area with exposure to morning sun will help with plant growth. If there are any bushes or trees near the location, make sure they don’t give a shadow till late in the afternoon.

If the location to the east is sunny and open, it will get plenty of sun from November till February. Since the winter sun has a low angle, trees, houses, etc. will pose an issue. Therefore, don’t select a place near evergreen trees. Deciduous trees don’t cause an issue since they lose their leaves in winter and will not shade the greenhouse.

2. Access to electricity

Make sure that the location you choose has access to electricity. Greenhouses need ventilation and heat to maintain optimal temperatures. If you are building a lean-to, you can get power from your home. In the case of a separate building, you will have to hire an electrician.

3. Well-drained area

Choose an area with natural drainage. Otherwise, you will have to siphon the excess rainwater. If the spot you chose is uneven, you will have to fill the area to help with drainage. You can use cisterns and catch the rainwater that falls from the greenhouse’s eaves. Later, you can use the conserved water for irrigation.

Choosing the suitable structure

Whether you build your greenhouse with a kit or from scratch, select the size very carefully. The larger your greenhouse is, the more money you will have to build and maintain it. For beginners, the optimal greenhouse size is 2.4 by 1.8 m.

A large open air terrace on a roof-top with a small greenhouse with plants

This will give you ample growing space. If you don’t have building experience, or you don’t have anyone to help you, you can buy a backyard greenhouse kit from local home improvement stores. You can choose any one of the three greenhouse structures below.

1. Build a lean-to

If you have selected a spot next to a building, you should construct a lean-to that will use the remaining wall for support. If the building has a brick structure, the heat from it will help in maintaining a steady temperature in the greenhouse. You can support the lean-to with wooden beams, rebar, and a few supports. Always choose high-quality building materials for your greenhouse project.

2. Make a Quonset frame

It is basically a geodome greenhouse that you can make using PVC pipes or steel supports. A doomed shape is better than rectangular models since there is less head as well as storage space.

3. Go with a rigid frame

You will require a sturdy A-frame and foundation with a rigid, cold frame structure. If you are a designer, you can create DIY greenhouse plans and build one yourself. If you are not, then you can search for free plans online. 

Finding the right covering materials

1. UV-stabilized polyethylene

You can use UV-stabilized polyethene as a covering material. It is cheap but is not BPA free. You can also go with LDPE grow tarps that are expensive but are non-toxic and long-lasting.

A greenhouse with polyethylene tunnels

You have to replace the plastic film after a few years. The life expectancy of PET plastic is shorter than LDPE. You may need to wash the greenhouse plastic covering occasionally. As compared to glass, it will not hold heat quite as well in cold climates. However, it is adequate for quonsets, lean-tos, and framed greenhouses. 

2. Double-walled plastic

You can also use double-walled, hard plastic like corrugated polycarbonate or multi-wall polycarbonate panels. You can curve the polycarbonate around the small greenhouse frame. Since it is double-walled, you will get energy savings of almost 30%.  

Since polycarbonate is about 200 times stronger than glass, it will not crack or chip. You can also use Plexiglass glazing which is expensive but has greater light transparency and is non-BPA.

3. Fibreglass

If you are going with a framed window greenhouse, then you should get fibreglass instead of glass since the roof construction will be lighter. However, in a couple of years, fibreglass glazing will start to yellow and lose its transparency. That’s why you have to buy high-grade fibreglass for better transparency. Acrylic is a better choice since it will stay clear for almost 10 years. Moreover, it is easier to work with as well.

4. Glass

Glass is an attractive material that will accentuate your greenhouse. You won’t have to replace it over time. However, it is expensive and fragile as compared to the options discussed above. Tempered glass is better than regular glass due to its strength and durability. Make sure that your frame and foundation can handle the glass weight, in case of high winds, hailing, heavy snow, etc.

Constructing the frame

Now it’s time to start with the building of your project! Are you ready? Grab your tools and take a look at the steps below:

Building a small greenhouse in a garden

  1. With the help of strings, mark the points where you want to set your supports. Affix your stakes in the ground.
  2. In the case of a Quonset or a lean-to, you have to reinforce the frame using PVC and  rebar. Place rebar every 1.2 m into the ground. 
  3. After the rebar is set, loop PVC tubing over the rebar and create the A-frame. Stretch plastic sheeting over the frame and then fix it to the bottom of the beams.
  4. Pour an even layer of gravel over the ground. It is better to use loose, small gravel for better drainage. If you want a foundation, you will have to pour concrete. 
  5. Treat the wood with a non-toxic, organic product before using it. If you don’t treat it, the wood will degrade in 3 years or less. We recommend that you use metal supports instead of wooden support, wherever possible.
  6. Bolt the plastic film to the metal/wood supports to seal it as closely as possible. 

Temperature control

1. Fans

Set up the fans in the corners of your little greenhouse. Make sure that they are diagonal and easily create an airflow. During the winter months, you will have to run fans constantly to distribute the heat evenly.

2. Vents

You have to install vents in the greenhouse’s ceiling. You can also install them near the top of the metal supports. They help with keeping a carbon dioxide-free greenhouse. Make sure your vents are adjustable so that you can open them wide in the summers and less in the winters.

3. Electric Heater

Since the solar heat will account for only 25% of the total greenhouse heat, you have to install a backup heater. An electric heater is a better choice than an oil or wood-based heater since they have to be vented to the outside. 

4. Thermometer

Install thermometers all-around your greenhouse so that you can keep an eye on the greenhouse’s temperature. 

A young woman in a glass greenhouse

A greenhouse provides the ideal environment for growing tender plants, veggies, flowers, etc. Whether you want to get a head start on your spring planting or whether you want to extend the growing season, a mini greenhouse will help you do that. However, traditional greenhouses are not only expensive, they are usually too large for an average backyard. Follow the steps in this step-by-step tutorial and know how to build a greenhouse on your own. But even if you don’t have the luxury of having a greenhouse in your backyard, you can still have one. You can build a tabletop greenhouse and bring greenery indoors.

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