Tips for Growing Indoor Ferns
With their fresh green colour and luxuriant growth, healthy ferns bring a hint of the tropical rainforest to your home or office. Naturally, it is a good idea to gather information on the kind of conditions these plants require before buying one so that your efforts will be crowned with success.
Ideal position for indoor ferns
Ferns of one species or another are at home in all the many different climatic regions of our planet.
Not all ferns, however, are happy to be grown indoors. Those that can be cultivated successfully inside our houses originate mainly from tropical or subtropical climates. Very often they come from rainforests where they grow on riverbanks, around springs, on mossy rocks or as epiphytes on tree trunks. Gardeners try to replicate these conditions for such plants in warm, shady with high humidity. Indeed, indoor ferns feel right at home in the tropical houses of botanical gardens. Moving into a modern house or flat, however, often requires drastic adaptation from such plants. To ensure that they are able to flourish in an ordinary room, certain minimum requirements with respect to temperature, humidity and light must be fulfilled.
Ferns with tropical origins, like many maidenhair (Adiantum), Davallia and Platycerium species, depend on even temperatures all year round. The ideal temperature in many cases is 25° C (77° F) but the usual room temperatures of
18-20° C (64-68° F) will be sufficient. During the winter or at night, the temperature may even sink to 16° C (61° F).
Ferns from subtropical or temperate regions, on the other hand, require slightly lower temperatures. Among these are Adiantum hispidulum, Cyrtomium falcatum, Pellaea rotundifolia andtsussimense. As a rule, they can manage at 16° C (61° F) in winter and even at 12° C (54° F) at night.
A basic problem is that the air in our centrally heated living rooms is far too dry for ferns. High humidity is particularly important for maidenhair fern (Adiantum),and Nephrolepis. These ferns will thrive best in either an enclosed plant picture window or in a glass case. An alternative is to stand these plants in rooms where the humidity rises, at least temporarily, to above the average, for example in a bathroom or kitchen. In other rooms additional measures to raise the humidity will have to be sought.
Ferns are reckoned to be undemanding with respect to light requirements. A couple of species do grow on the edges of woods or on cliffs where they are exposed to sun and wind, but none of the indoor ferns can cope with direct sunlight. This does not mean, however, that all species want to be in darkness. For most, a little filtered sunlight is ideal — a situation referred to as semi-shady.
East- and west-facing windows which receive only morning or evening sunlight are, therefore, ideal positions.
North-facing windows are only suitable for ferns that like dark positions.
South-facing windows are normally not suitable for ferns. If you do not want to do without ferns in such a position, make sure that in the spring and summer there is some shade during the middle of the day or move the plants away from the window.
My tip: Do not use your own perception of brightness as a measure for the light requirements of the plants. A position far to the back of a room, behind thick curtains, against an outside wall or in a corner may be too dark even for a fern. An accurate reading of the particular light intensity of any spot can be obtained from a luxmeter (obtainable in the gardening trade). Indoor ferns require at least 500-1,000 lux, depending on species.
The right fern for the right position in your home:
Ferns for shady positions :
Ferns that can cope with low humidity :
Ferns that are suitable for hydroculture :
Ferns for hanging containers :
Ferns to grow as epiphytes :
Ferns for moss pillars :
Small ferns for bottle gardens :
Adiantum "Fritz Luthi"
Fern plants can be found in nurseries, flower shops and garden centres. Accurate information on care, etc. is generally only available in specialist outlets.
Beware of plants:
• with meagre growth
• with deformed leaves
• with brown leaves, feathers or leaf tips (exception: the sterile leaf funnels of Platycerium)
• with dried up rootstocks
• with webs or pests on them.
Introducing plants to a new environment
• While the plant is settling down ensure that the best conditions are maintained, particularly sufficient humidity. The plants will have been accustomed to ideal conditions in a greenhouse and will require a certain amount of time to adapt to new circumstances, after which they are often surprisingly resistant.
• Newly purchased plants should not be transplanted immediately into larger pots. Usually, purchased ferns should not need to be repotted for a year or more.
• Do not start fertilizing for about four weeks as the compost in the pot nearly always contains enough fertilizer.