How to Build Your Own Backyard Greenhouse?


A Small Greenhouse

It's important to indulge in some meticulous planning before building a backyard greenhouse. Greenhouses can be built quite cheaply and with very little effort and time provided you follow the right process.

You will have to take the following aspects into consideration

  1. The grow space you desire
  2. Your budget
  3. The architecture of the greenhouse
  4. The site available

The end result is that the greenhouse should provide the right environment for your plants to grow.

Where to locate your greenhouse?

When you build a backyard greenhouse it should be located at a place that receives maximum sunlight. You mostly need to ensure that morning sunlight is amply available to the plants.

  1. Plan the greenhouse on the south side or southeast side of your house
  2. Avoid locating a greenhouse to the north side of a building, the only exception is if you are growing shade loving plants
  3. If there are deciduous trees in your backyard, locate the green house so that it gets some shade from the afternoon sun. These trees would shed their leaves by winter so the shade should not be a problem
  4. Build your greenhouse above the ground if possible. This will allow for good drainage especially after snow or during rains

Try to make the best of the yard you are working with. You will have to decide upon the size of the greenhouse based on the site available. You can decide to build a small greenhouse of plastic and pvc or a large one of metal frames and glass, depending on your site constraints.

The different types of greenhouses you can build

You can attach the greenhouse to your house or garage or create a free standing structure, just make sure the greenhouse location meets criteria sited above.

There are three basic frames that you can use for the greenhouse. They are

Rigid frame: This type of structure has vertical sidewalls and rafters. No columns are used to support the roof structure. You will need to nail in plywood gussets to attach the sides to the rafters. There needs to be a good foundation to support the sidewalls and the weight of the rafters.

A-frame: This structure involves the use of rafters as sidewalls. The rafters are joined at the top and at the collar. Strong embedment is required to keep the rafters in place.

Quonset: The frame is usually made out of galvanized steel pipe or pvc. The construction is in the form of a semicircle and the frame is usually covered with white plastic. This is the most basic and convenient structure for home garden greenhouses and it works out pretty cheap. If you are looking along the lines of how to build a small green house, then a Quonset frame structure is the best bet for you.

Different types of coverings used for the greenhouse


A Small Greenhouse Covered with Film Plastic

You can use the below materials as covering for your greenhouse

  1. Fiberglass
  2. Long-life glass
  3. Film plastic

Glass - This is a slightly expensive option for greenhouse panels but it allows for a more permanent structure. Using glass in an aluminum frame allows for a weather-tight structure which retains humidity and heat.

The disadvantage is that it is breakable and requires a very strong foundation.

Fiberglass - As a material it is strong as well as lightweight. Consider buying a good quality fiberglass that is completely translucent. It does tend to reduce its translucence with time but a good quality one maintains its clearness for long compared to a lower grade one. A fiberglass greenhouse can easily last for as long as 10 to 15 years.

Film plastic - The advantage with this material is that the structural cost is less. The frames can be made out of PVC pipes or other light-weight structures. Film plastics can be availed in several qualities and grades, most of them will last for 2 to 3 years quite easily.

Greenhouse foundation & flooring

If you are using glass, fiber glass or double layered rigid plastic as the covering material, then the foundation needs to be strong. A solid foundation is usually made out of pouring concrete as the base.

If you are using lightweight materials like PVC for the frames, to build a backyard greenhouse, then you can use a foundation made out of a wooden frame nailed into the ground.

The flooring can be made using a 3 to 4 inch layer of gravel or pebbles. This will also lead to better drainage. You can lay out a concrete path for walking between the plant stands.

Heating requirements of a greenhouse

To maintain the right amount heat inside the greenhouse is of critical importance. A good 25% of the heat inside may be obtained directly from the sun itself, even during winters. If you are wondering how does a greenhouse work in winters, well, you would need an artificial heating system to supply the rest of the heat especially during the evenings and the night time.

Some options to consider for a heating system are

  1. An electric heater (220 V)
  2. Gas or oil heaters
  3. Solar heater

The solar heater may not be very efficient if the days are cloudy and the nights are very chilly.

A few tips to improve the heating of your greenhouse are as below

  • Paint the frame black
  • Fill some milk cartons with water and paint them black, place them inside the greenhouse. They will absorb heat by the morning and emit it by night.

If you are using gas or oil heaters inside the green house, make sure the safety controls and gas shutoff switch are in good service. Heaters with no vents which use propane or kerosene are not recommended.

We hope you were able to garner some useful tips and pointers from this article on how to build a backyard greenhouse.