Hardy ferns are suitable for growing in the open garden, and tender tropical ferns are best cultivated indoors in a greenhouse or conservatory, or as house plants. Most hardy ferns are easy to grow and are suitable for shaded, moist conditions. Being very tough, once they have become established, they require minimum attention.
Most ferns prefer neutral to alkaline soil, except Thelypteris and all the Blechnum and Cryptogramma species which require acid soil. So a well-dug garden soil, with added humus will suit for most ferns.
Planting may be done at any time if you will use container-grown plants. In dry weather water them regularly until established. Always plant the ferns in full or dappled shade, in damp conditions which are necessary for the ferns to thrive.
Many ferns die down at the first touch of frost but there are some who retain their fronds well into winter. Leaving the old fronds on the plant until early spring will help to protect the crowns but you have to remove them in the moment the young ones start to uncurl.
Tender tropical ferns are the ones that will not withstand frost that is why they are making excellent indoor plants and we will talk about them in the indoor plants section.
Ferns are usually raised from spores but they may be propagated by division or by bulbils in some species. Ferns do not produce flowers or seeds. They have their unique way of reproducing. Fronds carry on their undersurfaces very small capsules called sporangia which release large numbers of powdery spores. Examine the undersides of the fronds to find one with sporangia that are ready to release their spores. Cut of that frond and place it on a clean paper to collect the spores. Sow a few of the collected spores in a pot filled with prepared sterile compost by tapping them from a piece of folded paper. Cover the pot with some clingfilm or place the pot in a propagator if you have one.
Mist-spray twice a week until the surface is covered with a bumpy green ‘moss’. Lift small clumps with a knife. Divide the clumps into small pieces and gently firm them down onto sterile compost. Spray with water and return them into the propagator. When leaf-like plantlets will appear is time to lift them carefully and firm into packs or small pots of moist compost. Pot on when they have developed small fronds.
Some of the hardy Polystichum species and Asplenium bulbiferum produce bulbils or small plantlets along the fronds. Select a frond that is drooping under the weight of bulbils. The bulbils may have tiny green fronds emerging from them. Cut off the parent frond close to the base. Peg down the frond onto a tray with prepared compost and make sure the frond’s ribs are flat. Water well and put the tray in a plastic bag. Seal the bag and put the tray in a warm, light place until the bulbils have rooted.
Remove the wire pegs and lift with a knife each rooted bulbil. If necessary cut it away from the parent frond. Put each rooted bulbil into a 7 cm pot filled with moist, soil-less compost. Keep moist in a warm, light place until the plants will be large enough to replant.