These tropical American plants are well adapted to house culture. I have seen plants with fifteen perfect flowers in the window of a humble cottage. We seldom get complaints about their failure. They are essentially summer flowering.
Gloxinias are raised in large quantities from seed by specialists, but the florist who grows only a few hundred will do much better to obtain his supply of corms (usually called bulbs) from some firm that raises them in large quantities. The price of the bulbs is now very low. Seed is usually sown in February. Sow on a wet surface and don't cover the seed; it is too small. Cover the pan with a light of glass till the seeds are up. A warm house is needed and the pans should be kept away from the direct rays of the sun.
As soon as the seedlings can be handled, transplant them two inches apart in flats in two or three inches of loam and leaf-mold. In June plant them in four inches of soil in a cold-frame, or better still, a hotbed that has lost its violent heat. When growing they like plenty of water, and should be shaded on all bright days. Many of these seedlings will flower the same summer and will make good bulbs for growing in pots the next season.
In September water should be gradually withheld till the foliage has dried up, when the bulbs should be lifted and stored away in dry sand or soil during winter. As previously said, for a few hundred you cannot begin to raise seedlings at the price you can buy good flowering bulbs from the specialist.
February to March is the best time to start the bulbs. We put them first in 4-inch pots, just covering the bulbs. One watering is sufficient till the leaves begin to start. A good loam with a third of its bulk composed of leaf-mold and well rotted cow manure will grow them finely. The house you start them in should not be less at night than 60 degrees, but as the season advances they delight in our warmest weather. When the leaves extend over the pots they should be shifted into their flowering pot, a 6-inch, and well drained.
Gloxinias really want a warm, moist temperature without any water lying on their leaves, although before flowering they should be daily syringed, which should always be done in the morning. I have had the best success with gloxinias when the plants stood on inverted 5-inch or 6-inch pots on the bench; you can syringe the under side of the leaves better, and the plants seem to thrive much better with the increased circulation of the air they get in this position.
Shading is the most particular part of their cultivation. They don't like the dense shade that whitewash affords, neither do they want the bright sun, or their beautiful flowers will wilt and droop. A light shade, or best of all, one that could be applied only in the hottest hours, would be ideal. Never let them get dry or you will lose their flowers. This is a plant that in watering I Should resort to the old watering pot, unless you have a very slow stream running from the hose and your mind intently on your work.
Bed of Canna Souvenir de Antoine Crozy Edged with Pecnisetam Longistylom.
The fine leaves of the gloxinia are very brittle and easily broken, and when shifting or handling must receive good care or your plant will be spoiled.
When out of flower, if you wish to keep over the old conns, lay the pots on their sides under a warm, dry bench and leave them undisturbed till you want to shake them out and start again in the spring.
There are now grand strains of most beautiful rich shades of color and the upright or erect flowering are the best.