This section is from "The Horticulturist, And Journal Of Rural Art And Rural Taste", by P. Barry, A. J. Downing, J. Jay Smith, Peter B. Mead, F. W. Woodward, Henry T. Williams. Also available from Amazon: Horticulturist and Journal of Rural Art and Rural Taste.
As soon as they are past blooming, give them a shift into good, turfy, rich soil, keep them in the house, and give abundance of water, both at roots and top, by syringing. When they have made good growth, gradually withhold water, and ultimately place them in the sun, on a hard gravel-walk if possible; keep dry and cool during winter, and they will flower profusely. Avoid the common practice of growing them in brick-dust and coal ashes, if you wish to see them flower in perfection.
Begonias are a valuable class for winter and spring flowering; shift now, and get a good growth before winter. Put in cuttings of heliotropes, salvias, cupheas, torenias, etc., for winter flowering, and sow mignonette and pansy seed for the same object.
The house should now be a mass of flowers; achimenes, gloxinias, and fuchsias, will be in perfection. Keep a moist atmosphere, and shade slightly during the hottest portion of the day. Exclude currents of dry air from passing over the plants, and keep the top lights open constantly, except, of course, during heavy rains. Tropaeolum bulbs should be kept perfectly dry; shake them out of the soil, and hang up in a basket in an open shed.