glass greenhouse with ladder in green garden

A greenhouse will allow you to grow vegetables and fruits all year long and will bring you lots of joy and yummie fresh food you can prepare. During the harsh winter months, you can heat your greenhouse and keep growing fresh vegetables. When you want to buy a greenhouse, there are a lot of decisions to be made. Which size of greenhouse should you go for? Which type of material suits you best and where’s the best place to build a greenhouse?

Glass, plastic foil or polycarbonate greenhouse?

The material of your greenhouse can consist of glass (safety glass), plastic foil or polycarbonate. The material that suits you best depends on your available budget and demands.

Glass greenhouse

Glass greenhouses were the original greenhouses and offer a beautiful addition to your backyard, especially the Victorian greenhouses are a real showstopper. Nowadays, most glass greenhouses are made out of safety glass, which is a lot stronger than horticultural glass. Even if this kind of glass breaks, it will break into small, harmless pieces. The glass can be clear, or can have a nice pattern on it. Often, the roof of the greenhouse is made out of hammered glass because this helps the light to shine evenly through the greenhouse and it breaks the direct sunshine. It usually has a positive effect on the growth of the plants, but take into account that it’s more expensive than standard clear glass. Glass greenhouses are extremely weather resistant and are the most durable kind of greenhouses. These are however also the most expensive greenhouses. Don’t worry if you feel this is investment is too high for you, polycarbonate and tunnel greenhouses are more budget friendly options!

Polycarbonate greenhouse

If you want to make sure there’s no risk of glass breaking and want to be sure of good insulation, polycarbonate windows are a good option. They are made out of double plates of polycarbonate and isolate 40 % better than glass, which helps the temperature in the greenhouse to stay stable. On top of this, the material is very strong, and the sunbeams are filtered. If you want to heat the greenhouse during winter, then polycarbonate is a good choice, given the insulation qualities it has. This type of greenhouse offers a lot of budget options, and you can buy a bigger greenhouse for a much lower price than the traditional glass greenhouses. A small disadvantage is that the polycarbonate is not as spectacular as a glass greenhouse and its lifespan will be a little shorter. Over the last years the quality of polycarbonate greenhouses has improved a lot, making it the perfect alternative for a glass greenhouse.

Tunnel greenhouse

If you are looking for the most budget friendly greenhouses, you will find the tunnel greenhouses might be your best option. These use polyethylene foils which are attached to an aluminum frame. Plastic foils will last 3 to 5 years, which is a lot shorter than the glass or polycarbonate alternatives. After a couple of years, the plastic greenhouse will become fragile due to UV beams and weather conditions. The most common reason to choose a tunnel greenhouse is the low cost and the possibility to move the greenhouse easily.

My first greenhouse was a polycarbonate greenhouse, and I would recommend this budget friendly and practical option to everyone who is getting started. The Victorian glass greenhouses are beautiful, but the investment might be too high when you’re just getting started. Tunnel greenhouses can protect your plants but won’t give you the heating options during winter and you won’t be able to roam around in them and enjoy the peace and quiet my greenhouse offers me.

Which material should your frame be?

Wood or aluminum

Wooden frame greenhouses are less and less popular. They are very classy and beautiful because of their natural look and feel, but they are a lot more expensive than aluminum frames. Wooden greenhouses of good quality are usually made out of Canadian Ceder wood. This wood is resistant to humidity and is not influenced by temperature difference.

Aluminum greenhouses are light and durable. They can’t rust and need a minimum of maintenance. Another benefit is that aluminum greenhouses have very narrow grooves which allow a maximum of light to reach the plants. Because of the light construction, it’s important to anchor the foundations carefully; you don’t want the wind to blow your greenhouse away!

How large should your greenhouse be?

The size of a greenhouse is very important as it determines the number of plants you can grow in them. And a greenhouse is filled more quickly than you might think! You begin with a couple of tomato plants and some cucumbers, but other plants will follow soon and before you know it your greenhouse is full. It’s best to think about how large your greenhouse could eventually become before you decide to buy one.

In a larger greenhouse, the temperature will be more stable than in a small one due to the bigger volume. The more stable the temperature, the better your plants will grow. In a large greenhouse, it’s also easier to work and plant. Next to the benefits for your plants, it’s also nice for you to be able to roam around in a greenhouse and not bump against shelves and pots every time you turn around.

It might seem hard to decide on what size greenhouse you need, but we can help you out as we have a whole article about your perfect greenhouse size!

The importance of ventilation

A greenhouse needs to have at least one skylight per roof plane. Ventilation is very important as a greenhouse without skylights can become too hot during summer. With good ventilation, you also prevent the humidity to rise. You can open the windows by hand or install a hydraulic system that opens the windows automatically. These are not very expensive (they start at 75 dollars) and are easy to install. They will automatically open the windows in the greenhouse when the temperature rises above a certain temperature and will close them when temperature decreases. At the front of the greenhouse, it’s best to have a broad door, to make it easy for you to enter the greenhouse with a wheelbarrow. Skylights should be placed on the east side of the greenhouse, away from the cold Northern wind and the rain side.

Best place to install a greenhouse

While a greenhouse used to be purely functional and was often hidden in a corner of the yard, these days, people like to place the greenhouse in the center of the backyard and make sure the design is in harmony with the atmosphere. It’s usually placed in a sunny place, with not too much wind. Don’t install your greenhouse in a place with lots of shade; this will limit the number of plant types you can grow.

In general, a southern orientation (with the entrance south) is the way to go as the greenhouse will receive lots of sun in the summer and will benefit from every available ray of sunshine during winter. If you however live in an extremely hot climate, it might be better to face your greenhouse east to avoid temperatures from rising too high during spring and summer.

It’s best to place your greenhouse not too far from your house. It’s a place that you will be spending lots of time in, and if you would like to install water or electricity pipes, it’s easier if the greenhouse is close to the house.

Heating the greenhouse during winter

An average hobby greenhouse is usually meant to grow plants that have a hard time growing in open air, such as peppers, tomatoes, eggplant, paprika, and melon. When you want to use your greenhouse to have some of your outside plants survive winter, you will need to heat your greenhouse. There’s a lot of options for heating your greenhouse, but electricity or gas are the most common.

No matter which system you choose, heating your greenhouse during winter can get a little expensive. It’s definitely necessary to insulate the greenhouse, for example with bubble wrap. A greenhouse with double sided polycarbonate is automatically better insulated, which can make a big difference in energy costs. When possible, always install a thermostat (low to the ground). This will not only help you keep the temperature in the greenhouse steady, but in the end, it will also help you to lower your energy costs.

Foundation

The foundation of your greenhouse is very important, as it will protect it against all possible pressure rising from the ground. Frost during winter can make the ground water rise unevenly into the foundation, and during summer, the heat can make the ground sag.

A self-supporting aluminum foundation creates a perfect protection that can cope with the seasonal weather circumstances. It makes sure that the ground in the greenhouse is not separated from the ground outside which helps you not to have to renew the ground in the greenhouse. Another advantage of the aluminum foundation is that it’s possible to move the greenhouse, so you don’t have to leave your hard work behind.

When you choose a concrete foundation, you have to make sure the foundation is set 23” to 25” in the ground, right underneath the frosting border. The platform that will hold the greenhouse needs to be levelled and flat at the side of the facades and needs to be curved on the surface over the entire length of the greenhouse so the rain water can flow away.

Lighting

The most important life element for our plants is light itself. Lots of failures on growing plants, seeds and flowers find their cause in a lack of light. Especially between the middle of October until the end of April, the days are too short to be sure of strong plant growth. Young plants especially can go yellow, lose their bottom leafs or sadly just die.

A general rule is that plants need light about 14 hours per day if they want to grow well. Even the plants that are just in the greenhouse to survive winter need this amount of light. This means that during winter an average of 6 hours per day extra light is needed, ideally during the evening, for example from dawn until bedtime.

About the different forms of artificial light and the different lamp types, there has already been a lot of scientific research and a lot of articles. When you’re a hobby greenhouser, we can recommend you our article concerning greenhouse lighting.

The ground

As the basis for your greenhouse, you need sterile, organic soil that is weed free. Before starting to grow, you need to bring the ground and the greenhouse to the right temperature.

Every fertiliser in the greenhouse needs to be organic, make sure to use good digested stable fertiliser, compost or dried fertiliser. For the extra fertilisation that is almost always necessary under glass, chlorine-free mineral fertilisers should be used. This is because the greenhouse will need sowing and harvesting 2 to 3 times a year, so the fertiliser is a key element in the success of the greenhouse.

Buying a greenhouse

A simple polycarbonate greenhouse of about 6 to 8 feet is available as of 450$. Prices of bigger models vary between 700 and 3000$. Glass greenhouses are more expensive and cost between 2000 and 4000$. The price of a greenhouse is mostly dependent on the type, the kind of frame, the surface finish, the kind of glass, the foundations and the volume. Check out our article about the best greenhouse for your budget!

Congratulations, you are now ready to install the perfect greenhouse for you and get started! Still in doubt whether growing in a greenhouse is the way to go for you? Let us convince you!