What are the Best Greenhouse Flowers?

Cynde Gregory

Greenhouses are wonderful for extending the growing season in areas with long periods of cold for growing flowers that don’t typically flourish in an outdoor environment. The best greenhouse flowers include all types of orchids and lilies, biennials such as foxgloves, perennials such as lupine or delphinium and annuals of all sorts. In general, the best greenhouse flowers are those that appreciate a warm, humid environment.

Calla lilies are wonderful greenhouse flowers.
Calla lilies are wonderful greenhouse flowers.

There are a number of benefits that greenhouses provide to flowers that outdoor gardening does not. The environment is protected, so plants won’t be knocked over or damaged by high winds or scalding sunlight. The heat, even in an unheated greenhouse, is easier to regulate; as long as the greenhouse isn’t allowed to become too hot, the best greenhouse flowers will be those that prefer to set buds at a uniform temperature. Greenhouses also offer some protection again insects and many diseases. Flowers that are especially susceptible to white fly, voracious beetles, June bugs and other garden pests as well as diseases spread by these insects are a good choice to be grown in a greenhouse.

Flowers that grow best in warm and humid weather, such as orchids, lilies, biennials, perennials  and annuals, often grow best in greenhouses.
Flowers that grow best in warm and humid weather, such as orchids, lilies, biennials, perennials and annuals, often grow best in greenhouses.

Among orchids, phalaenopsis, cattleya and ontoglossum orchids do especially well in regulated greenhouse environments. Odontoglossum prefer a cooler greenhouse. These beautiful orchids set buds in fragrant sprays and are happiest in a greenhouse where night time temperatures can be held at 55 degrees Fahrenheit (12.8 degrees Celsius) and daytime temperatures don’t rise above 75 degrees Fahrenheit (23.9 degrees Celsius). They thrive in filtered light and even humidity.

Cattleya orchids prefer intermediate temperatures between 60 degrees Fahrenheit (15.6 degrees Celsius) at night and 85 degrees Fahrenheit (29.4 degrees Celsius) during the day. Phalaenopsis orchids demand the most heat. They are intolerant of night temperatures below 65 degrees Fahrenheit (18.3 degrees Celsius) and will withstand a hot, humid environment of up to 90 degrees Fahrenheit (32.2 degree Celsius).

Calla lilies make excellent greenhouse flowers. Native to South America, their long, tube-like blossoms end in an open flute. They require shaded or filtered light and will become stressed by an overabundance of sunlight. It’s important for gardeners growing calla lilies to maintain even dampness in the soil and not permit it to dry out.

Biennial flowers such as foxgloves that normally require two years from planting to flowering are another excellent greenhouse choice. Gardeners can plant the seeds in the fall so that they have a garden-ready plant by spring for planting out. They might instead choose to keep the flowers in the greenhouse year-round, where they will often continue to set flowers for several years before burning out.

Perennial flowers such as delphiniums or lupines also make terrific greenhouse flowers. Lupines, which are from the pea family, produce blooms on tall stalks that can suffer from wind damage. They grow best in a cool greenhouse. Like lupines, the tall flowering stalks upon which delphinium blossoms grow are susceptible to strong wind and are especially delicious to many garden pests. The greenhouse environment can provide a protective year-round growing season or be used to prepare seedlings for planting out into protected outdoor areas.

All types of annuals get a head start as greenhouse flowers. By planting seeds in mid-winter, gardeners will have plants ready to burst into bloom when the time is right to plant them outdoors. Annuals that begin in greenhouses can range from impatiens to scabiosa.

The best greenhouse flowers thrive in a warm, humid environment.
The best greenhouse flowers thrive in a warm, humid environment.

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Discussion Comments


If you aren't going to be growing them commercially, I'd say your best bet for research is to go to the local botanic gardens or big park and take a look at their public greenhouse.

They will usually have a wide range of different kinds of plants and greenhouse structures so you can see what would suit your home and your ability to care for it, as well as what would suit your tastes.


@pastanaga - They don't really take a huge amount of time to care for once you've got them established. I think they have a reputation for being difficult because they are fussy, but if their needs are catered to they don't really need a lot of tending.

You do need to do a lot of research on them first, though, because they need to have very particular growing conditions and these vary according to the type of orchid. Some of them need to be grown on trees and most of them will need a particular kind of fungi in their roots in order to live.

If you are new to greenhouse gardening, I wouldn't start with orchids as a general rule, although I know people can be very passionate about it. It can be extremely discouraging when they fail to thrive because a single element isn't right.


I have always wanted to grow orchids. I think they are so beautiful and so diverse whenever I see them in a public flower greenhouse. They are always the thing I rush to go and see.

They are supposed to be very difficult to cultivate well, though, apart from a few commercial varieties that aren't particularly interesting (to me, at least). So I've never dared to start a collection, because I don't really have the means and the time right now to make sure that they will survive.

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