Ferns are relatively easy to grow and if they are protected from dry air and temperature extremes they will have lush green fronds throughout the year.
There are a lot of species of tropical and subtropical ferns and these are best suited for a greenhouse. There are many species that are native to more temperate climates. These can be grown in a greenhouse but only if it is kept on the cool side.
Although most ferns grow in moist shady places like forest floors, this does not mean that they need no light. Their normal situation in the wild is dappled light, and if the light level is too low, you will see poor growth and yellowing fronds. Give them a position in the greenhouse that gets morning or late afternoon sun, and keep the them away from strong sunlight, especially during the summer. Direct sunlight will make them lose their leaves or turn their fronds yellow. Ferns can be kept in dim light as long as they are given regular breaks in bright light. They can be given artificial light, but this should be from a fluorescent strip.
Ferns should be given humid conditions and do well their pots are placed on trays of damp pebbles or clay granules. Ferns also love being misted at regular intervals with tepid, water unless the humidity of the whole room is kept high through the use of a humidifier.
Most ferns are forest or woodland plants and have tender, delicate roots adapted to the light forest soil, which is rich in leaf mold and decayed vegetable matter. The soil must be free draining and never allow the roots to get waterlogged. Soil that contains peat or a fibrous peat substitute with plenty of sand is best. The soil should never be allowed to dry out, which may mean watering the plant a little every single day in a warm, dry atmosphere.
An individual fern’s place of origin and adaptability will determine how high or low temperature the fern needs. Most ferns don’t like cold and those from tropical regions should be kept at 60-70 F. Those from more temperate regions enjoy temperatures between 50-60 F. (10-16 C).
Fertilize ferns in the summertime every two to four weeks with a liquid fertilizer, but don’t mix it full strength because you can damage the root system. Just a few drops of fertilizer can be added to the water occasionally for misting. Do not fertilize them in the winter months.
Ferns should be re-potted in the spring, but only if their roots are filling the pot. Otherwise, just scrape off the top layer of soil and replace it. Remove any damaged fronds to encourage new growth. When you re-pot your ferns, split them up and make two out of one. New ferns can be grown from the powdery spores produced in little capsules. These capsules are visible as rows of rusty brown patches on the underside of the fronds. These will grow into a green film into which the fern will grow.
Ferns are a very old group of plants. They first appeared on Earth in the middle Devonian Era about 360 million years ago, just before the Carboniferous Era. Most of the modern fern families we see today first appeared in the Late Cretaceous about 45 or 50 million years ago, during the dinosaur age.