The Spleenworts

From The Encyclopaedia of Ferns An Introduction to Ferns, their Structure, Biology, Economic Importance, Cultivation and Propagation by David L. Jones ISBN 0 88192 054 1:-

"Aspleniums are prized for their frond symetry, frond texture, sheen and neat growth habit. They generally succeed very well in cultivation.

Habitat
Aspleniums may grow along stream banks, but prefer large, mossy boulders. Most aspleniums grow in a moist, humid environment but a few can withstand 4-6 months of dry weather.

Cultivation
Aspleniums make excellent pot subjects and prefer to be underpotted than overpotted.
The larger growing types can be used in tubs (Asplenium oblongifolium, Asplenium australasicum).
Many epiphytic species are well suited to hanging baskets, especially those with drooping fronds (Asplenium bulbiferum, Asplenium polyodon).
Some are excellent for indoor decoration (Asplenium dimorphum, Asplenium simplicifrons).
Robust, large growing species are useful in a general garden situation (Asplenium oblongifolium, Asplenium scleroprium) and
the more delicate types can be grown in rock gardens, walls etc (Asplenium adiantum-nigrum, Asplenium trichomanes)

Soil Types
In the garden, Aspleniums and their relatives need well-drained loam fortified with organic matter. Most species prefer an acid pH (5.5-6.5) but some require neutral to alkaline conditions. Organic mulches are very beneficial.

Potting Mix
An open but fibrous mix endowed with organic matter is generally suitable. A mix well fortified with tree-fern fibre or osmunda fibre is usually to their preference. As a group they resent poor drainage and must be repotted as soon as the mix shows sign of breaking down.

Watering
Aspleniums like plenty of water during the warm growing months but are best kept on the dry side during winter. This is especially important in the UK where winter temperatures are low and the photoperiod short.

Fertilizing
Slow-release fertilizers in the potting mix are beneficial. Potted plants also respond to liquid fertilizers applied during the warm, growing months. Plants in the ground like a spring dressing of blood and bone, well-rotted animal manure (Cow manure contains no weed seeds since the cows have eaten the food 4 times) or compost.

Situation
Aspleniums generally like well lit conditions but must be protected from excessive hot sun. Exposure to morning sun or filtered sun is ideal. They also need fairly high humidity and appreciate air movement, but not excessive wind, draughts or stagnant conditions. Frosts are tolerated by the hardy species from temperate regions but are very damaging to those from the tropics. In temperate regions these types will need the protection of a heated greenhouse."