Taken from wikipedia's page at: http://en.wikipedia.org/wiki/S...
"Each grower will have their own preferences for cultivation. The details given below are a tested general guide, but Streptocarpus will do quite well on either side of these optimums.
The two main things to remember when growing Streptocarpus are that they do not like soil that is too wet, and they do not like it too hot.
Soil: Use an ordinary commercial potting mix with 1/8 to 1/4 perlite mixed in. This makes sure the soil will retain some moisture but not get boggy. Always have adequate drainage holes at the bottom of the pot you are planting in.
Temperature: 18°C-25°C (64.4°F-77°F). They can be taken down to 10°C (50°F) or less in winter for a rest.
Light: Medium to bright indirect light is best. However, a bit of morning/late afternoon sun is more than OK. Even in dimmer light, they will flower - but less floriferously.
Water: Water only once the soil is almost dry. Some grower prefer to water only when the leaves have just started to wilt (or just before). They recover very well from dehydration, and is one of the traits of the species. Make sure the pot has holes in the bottom to drain water, and never leave the pots sitting in a saucer of water.
Feeding: Feed occasionally with a "fruit and flower" or general fertiliser.
Seasons: Generally, Streptocarpus will flower from spring to autumn. In winter, they will stop flowering and may lose some leaves, which is normal. However, some varieties flower in winter.
Pruning of leaves & flowers: You may slice off yellowing or browned leaves at the base - these will be the older leaves naturally dying off. If there is a healthy leaf with some blemishing, you can successfully cut off only the blemished parts and trim the leaf to a normal shape. With regards to flowers, snip off individuals as they finish, then snip the whole stem off at the base once the last flower on that stem is spent.
Cut flowers: Streptocarpus flowers are also make excellent cut flowers, especially the long-stemmed varieties. They last well.
Pests and diseases: Streptocarpus are generally pest and disease -free. However, the most common afflictions are aphids and mealy bug. These are easily treatable with commercial insecticides or cultural pest removal methods.
Leaves and abscission: It is common for older leaves to die off occasionally, but especially in winter. They may be snipped off. New leaves will replace them.
The leaves of some perennial, but usually unifoliate Streptocarpus, are unusual because, as winter approaches, they slowly die back to an abscission line (see picture gallery below) midway down the leaf. The end portion of the leaf will gradually die back to this line. In most flowering plants, an abscission line forms at the base of the leaf, and the whole leaf will fall off (e.g. the leaves of deciduous trees like oak)."