Large trumpet-shaped blossoms of this gesneriad are of velvety texture, so beautiful they defy description. Hybrids are available in just about every color except yellow.
For your first gloxinias, purchase tubers from a gesneriad specialist or your garden center. Plant one tuber to a 5- or 6-inch pot, the concave (indented) side of the tuber up. Cover tuber with about ½ inch of potting medium which must be fibrous, loose, well-aerated, and quick draining. Gentle bottom heat is helpful in starting growth, but not essential. Pots can be placed in any convenient warm spot, but as soon as growth appears above soil, move to good light but not direct sun. Growth will now be rapid; all shoots except the main one should be rubbed off as they appear a gloxinia should always be grown with a single crown if you want a handsome plant that produces flowers superior in quality and quantity. (However, you can let the secondary shoots grow to about 2 inches, gently pull them from the tuber and place them in a propagating case to root.)
Fertilize growing gloxinias every 10 days with a complete house-plant fertilizer, keep evenly moist but never soggy, and try to provide relative humidity of 50 to 60 per cent. After flowering, keep foliage growing until it yellows and dies back, indicating that the tuber has become dormant. Twist off dead foliage and water soil occasionally, just enough to keep tuber from shriveling. A new growing cycle may start in a few weeks, or the tuber may rest for three months just watch for new growth, then repeat cultural instructions above.
Gloxinias grow very easily from dustlike seeds. Sow on top of moist milled sphagnum moss, mist lightly with warm water to anchor seeds to moss. Enclose container in plastic and give it bottom heat and light (but not direct sun). Germination takes 10 to 30 days the fresher the seed the faster it germinates. For a specimen plant with abundant flowers, transplant the seedling directly to a 5- or 6-inch pot, where it will flower in 6 to 8 months. For earlier but smaller and sparser flowers, transplant seedlings to 3-inch pots. (Caution: the tuber starts to form underground as soon as germination occurs be careful in transplanting seedlings not to separate the tiny tuber from the top growth.) Culture for seedlings from this point is same as for tubers. Gloxinias are also easily propagated from leaf cuttings.