How To Choose The Correct Greenhouse For Your Garden
Firstly let’s look at the many benefits of having the correct greenhouse in your garden
- In Ireland and other parts of the world a greenhouse allows you to extend your growing season, and produce crops 12 months of the year. Because it allows you to grow in a somewhat controlled environment.
- The correct greenhouse allows you to produce spring and summer crops much earlier in the season this is because the temperature even in an unheated greenhouse will be several degrees higher than outside temperatures.
- It is possible to raise plug plants from seed to plant out in your garden once the weather is suitable.
- When using a greenhouse in your garden you can grow tender plants that you couldn’t otherwise grow. For example here in Ireland it is not possible to grow tomatoes successfully outside so a greenhouse is a must.
- A greenhouse gives you somewhere to garden even on a bad weather day.
- If you have spare space you can use your greenhouse for other functions for example storing wood or drying clothes. This is especially useful if you live in rainy Ireland.
What Are The Main Types of Greenhouse?
There are three main categories of greenhouses. Polythene tunnel’s, glass houses and polycarbonate houses. Each greenhouse has its advantages and disadvantages we will look at each to help you make the correct decision for your garden.
Polythene Tunnel Pros And Cons
Pros | Cons |
Good value for areas covered | A little colder inside than other options |
Available with high roof so high growing space | Difficult to harvest rainwater from sides |
Easy to construct and can be done quickly | Polythene needs to be replaced after approx 10 years |
Replacement covers readily available | Polythene can be pierced easily |
Very little maintainence | Not as pretty as a glasshouse |
Glasshouse Pros And Cons
Pros | Cons |
Glasshouses are a few degrees warmer than polythene tunnels | Highest cost option per area covered |
Looks great in a garden and looks better than other options | Can be difficult to construct and in most cases it is better to get a fitter to install. |
Solid in construction and generally lasts for a lifetime | Glass can break quiet easily and replacement can be difficult to find |
Easy to harvest rainwater from the roof. | Moving parts such as doors and windows can give trouble. |
Easier to heat than other options | Needs to be on a flat solid base so there is ground works prior to assembly |
Polycarbonate Greenhouse Pros And Cons
Pros | Cons |
Polycarbonate greenhouses are a few degrees warmer than polythene tunnels | Polycarbonate is around a longtime earlier versions were poor quality. Although it has vastly improved it remains unproven over a long period in my opinion |
A beautiful looking greenhouse in the garden | Constrtuction needs to be perfect or wind can cause damage because the panels are light in weight |
Solid in construction and polycartbonate has improved in quality so it should last a long time | Polycarbonate can discolour over time again polycarbonate has improved in quality so may not be an issue anymore but remains unproven over time |
Rainwater can be harvested on some models | Tends to require more ventilation than the other types |
Is generally a little less expensive than glasshouses | Needs to be on a flat solid base so there is ground works prior to assembly |
Let’s look in more detail the correct greenhouse for you
Polythene tunnels
Polythene tunnels are covered with UV stable polythene that has a guaranteed lifespan in terms of UV breakdown is 7-8 years. I personally got 17 years from one polytunnel I had. It is important the the plastic is really tight and that if you get any damage in the polythene you repair it immediately, If you don’t it can spread quickly and can be taken away completely on a windy day. Polythene tunnels are a couple of degrees colder than a glasshouse or polycarbonate greenhouse because the thermal holding capacity of the polythene is less than glass or polycarbonate. If you are growing fruit and veg and just want a greenhouse to extend the growing season then a polytunnel is the perfect choice. Polytunnel’s also give much greater covered area for your spend than the other options because they cost less per square mtr than either glass or polycarbonate.
Glasshouses
Glasshouses are warmer than polythene and so if you are looking to grow tropical plants or raise bedding plants earlier in the year then a glasshouse is a good option. They do look quite good in a garden and in many cases combine as an area to raise plants and a nice spot to sit with a cup of coffee and a book. Glasshouses in my opinion are a great choice where space is limited. If the aesthetics are important and if you are looking for a greenhouse on a smaller scale. The few degrees extra heat that you get in winter and spring may be a decisive factor for some people depending on what you are growing.
Polycarbonate house
The quality of Polycarbonate greenhouses have improved over the last 4-5 years. The polycarbonate panels in the greenhouse have improved and they look much better than the original versions. They hold heat better than polythene tunnels this means you can grow a greater range of plants. Polycarbonate greenhouses are more economical than glass and you get a bigger house for your spend. My only reservation at the time of writing is that these new models are only on the market 4-5 years and I would like to see how they are performing after 10-12 years. This opinion may be influenced by the fact that the first versions from 10-15 years ago were troublesome. I believe polycarbonate greenhouses will become more popular over the coming years.
With all this info, which is the correct greenhouse for your garden?
This all comes down to personal choice. You will need to take into account what you plan to use the greenhouse for, the area you want to cover and whether the aesthetic is important to you. Look at all the options to make the right choice for your garden. It is important when you buy your greenhouse you should always buy a bigger greenhouse than you think you need.
Because. when you get a small greenhouse you will quickly find it full of plants and as a result you will wish you had a bigger greenhouse.
Whichever you choose a greenhouse is a great addition to any garden.
Here is a link to a my podcast covering the same topic with Brendan Doyle of D-Plant Horticulture who manufacture polythene tunnels.
John
