What is the Difference Between a Greenhouse and a Glasshouse?

Greenhouses and glasshouses may be terms that are commonly interchanged, but are they one in the same thing, or is there a difference? Here we look at the individual definitions of greenhouses and glasshouses, and offer bonus tips on how to make sure your glass building is warm enough to ensure your plants safely survive the winter cold.

greenhouses and glasshouses

What is a glasshouse?

A glasshouse is a building made of glass in which plants grow faster than outside. The glass traps the heat from the sun inside the building to boost the rate of growth of the plants. Glasshouses tend to be used more in a commercial setting, to grow vegetables and plants for sale in nurseries, for example.

What is a greenhouse?

A greenhouse is also a building used to grow plants, and features large windows. Similar to a glasshouse, it traps heat from the sunlight, which helps the plants inside to grow, and also keeps them safe from frost over winter. Greenhouses tend to be used domestically rather than commercially, however, and are not always made completely from glass. Some have timber frames, often constructed from Western Red Cedar to aid their thermal properties, and others are made from polycarbonate.

If you are looking to keep tender plants safe over winter, or bring on seedlings ready for planting outside, it is important to be aware that it is not possible to make a greenhouse completely safe if the outside temperature falls substantially below zero degrees Celsius.

As a rule, you can expect the difference between the outdoor temperature and the temperature inside a greenhouse to be around two degrees Celsius. Each degree near to freezing is critical for plants, especially those that are not frost hardy. For this reason, if you are looking to protect young or tender plants throughout the winter, you are going to need to heat your greenhouse. The good news is that this is a relatively simple undertaking.

How to heat a greenhouse

A minimum of 4º or 5ºC is a safe temperature to maintain overnight if you want ensure your plants are kept safe against severe snap frosts. Installing a thermometer will help you keep track of the inside temperature of your greenhouse.

One of the easiest ways to protect potted plants in a greenhouse is to use a heated propagator. Group plants together with similar temperature needs, and place them in the propagator, using the thermostat to control the temperature automatically as the weather changes. This is a good way to keep particularly vulnerable plants protected from frost.

Greenhouses and Glasshouses

Another way to safeguard your greenhouse plants over winter is to reduce heat loss through the glazed areas. This can be done simply using bubble wrap fixed on the inside of the windows. Make it a temporary measure though, as you’ll want to ensure plenty of light flows in during the summer, and of course, you’ll want to be able to clean the windows. Horticultural fleece is another option. Available from greenhouse accessory suppliers, this is used to protect the roots from the cold.

There are also custom greenhouse heating systems that can be installed. These range from providing subtle background warmth, to continuous heating. Generally, they will be thermostat controlled, so that the heating only kicks in when temperatures fall dangerously low. This keeps heating costs down, and ensures there is no energy wastage.

Another way to heat a greenhouse is with the use of soil warming cables. This is an economical solution, heating the soil either in a bed, or propagation bench. Easy to install, the cables provide heat where it is most needed, at the roots. So, even if top growth is damaged by frost, the roots will survive. If you have young plants that need protecting, soil warming cables are ideal, and work well in conjunction with horticultural fleece which keeps the heat in.

Thinking of investing in a greenhouse? Look to Surrey Hills Garden Buildings.

Here at Surrey Hills, our quality greenhouses come from Britain’s leading manufacturers. All feature toughened glass and a unique capping system to make certain your plants are kept warm and dry. We also supply a range of greenhouse accessories, including plant display staging, fixing kits for hanging baskets, water collection systems, shading and fleeces as well as heating and ventilation solutions.

Why not come along to one of our dedicated show sites and view our greenhouse range for yourself? Our friendly experts will be on hand to provide all the advice you need, guiding you through the different styles and models to help you choose the greenhouse that suits you best. Alternatively, you can get in touch to discuss your greenhouse requirements.

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