Greenhouses are very helpful when growing Tropical plants in less than ideal conditions. Growing tropical hibiscus in a greenhouse is necessary when you live in a sub-tropical environment, like myself, and it can be a complex organisational feat to shoe-horn a large enough greenhouse into a small yard. Trust me, my back yard is quite small. Although, if you can manage the space, you’ll be rewarded.
I live in the inner city of Melbourne, so my backyard is small, however it’s not exactly a small courtyard either. I have a small grassed area, a gravelled area and an undercover area. And still enough space for the dog to run around.
Our winters are far too cold to house hibiscus outdoors, and as I grow in pots I need an adequate shelter for them during the coldest months where temperatures are regularly below 10 degrees celsius.
Consider the following if you want to grow tropical Hibiscus in a greenhouse:
Size of your collection
The size of your hibiscus collection will determine the size greenhouse you need. I have around 300 plants stored in my 4.3m x 2.3m (14.1ft x 7.5ft) greenhouse. There’s no point in buying or building a greenhouse too large or two small for the plants you have. You do want to plan for growth, but within reason.
Space in your back yard
You need to have a greenhouse big enough for your collection, but small enough to still fit in the available space you have to place your greenhouse. The available space you have in your back yard is the biggest limiting factor. A small courtyard could house a small greenhouse that is the equivalent of a small shelf. How much space you want to dedicate to your collection will determine the size of your collection.
Position for sun
You want to maximise the heat that the greenhouse can store. There’s no point putting it in the shade. Find a position that gets between 6 – 8 hours of sunlight per day. A north facing aspect is better than a southern facing aspect. Especially if you are in South Australia or Victoria where the sun never goes over-head in winter.
Air exchange needs to happen regularly to prevent mould and fungus from taking hold. Ensure your greenhouse has vents or the ability to exchange the air once a day. Either by opening a door/window or via an extraction fan.
If you have a small back yard you may want to take your greenhouse down in summer. Consider summer storage of your greenhouse. Although it would be possible to use it all year round. Australia does get severe summer heat.
Where you live
If you live in the northern states of Australia, or the northern half of New South Wales, you don’t need a greenhouse at all. You only need to grow hibiscus in a greenhouse if your coldest temperatures are regularly below 10°C in winter.
No matter where you live, you can keep these sun loving plants in any of Australia’s states. Just keep them as warm and protected in winter as you possibly can. Which may even involve bringing them inside where there are frosts about.
Growing hibiscus in a greenhouse makes your plants happier in winter, will protect them from frost and cold air and keep them in good condition for the next summer season.