Gesneriads

Temperature:
60-65 F

You could devote several greenhouses exclusively to gesneriads and still not have enough space. The best known gesneriads are African-violets (Saintpaulia) and gloxinias (Sinningia) but at least forty other genera, each with from one to countless species and hybrids, are popular warm-greenhouse plants.

General requirements are a very porous well-drained potting medium, relative humidity of 45 to 55 per cent, excellent air circulation around the plants but no direct drafts, regular fertilizing while plants are in growth, water frequently enough to keep the medium moist but not soggy, prompt removal of fading flowers and deteriorating foliage, and (ideally) enough space so plants do not touch each other.

This family, Gesneriaceae, includes tuberous-rooted plants as Chrysothemis, X Gloxinera, Rechsteineria, and Sinningia; rhizomatous-rooted plants as Achimenes, Diastema, X Eucodonopsis, Gloxinia perennis, Koellikeria, Kohleria, and Smithiantha; and fibrous-rooted, usually evergreen, plants as Aeschy-nanthus, Chirita, Codonanthe, Columnea, Episcia, Hypocyrta, Nau-tilocalyx, Nematanthus, Saintpaulia, and Streptocarpus.