Daylengths of less than 12 hours can result in single flowers and tuber formation. A minimum daylength of 14 hours can be provided using supplemental light. This daylength can be provided continuously or as night-interruption lighting. Ten to 15 footcandles prevent tuber formation.

Once germination occurs, allow the medium to dry out to prevent algae formation. If seed is sown in smaller plug trays or in open flats, transplant seedlings into larger plugs, usually five weeks after sowing. A 72-cell plug tray gives plants adequate space to fill in. As seedlings develop, lower temperature to 72F-75F.

Plants should be ready to be transplanted into finished containers (606 cell packs, 4- to 6-inch pots and hanging baskets) in another four to five weeks (about 10-11 weeks after sowing). For growing on, lower the temperature to 68F-72F.

Fertilize with 150 parts per million nitrogen on a constant-feed basis. Begonias are sensitive to high salts. Electrical conductivity level should be kept ideally at between 1.8-2.2 to prevent leaf edge burn. It can go as high 3 without problems.

Supplemental light (230-250 footcandles) during production can be beneficial. Higher light levels can be used to keep the plants compact. A daylength of 14 hours is necessary to keep the plants vegetative.

Some shading may be needed during spring and summer to prevent leaf burn from high light levels.

Plant growth regulators aren't necessary under normal production conditions. If a PGR is needed, Cycocel at 300-500 ppm is effective. Fortune begonias branch well and stay compact, 10-11 inches.

Plants in 4- to 6-inch pots finish 16-17 weeks from sowing. Three to five plants in 12-inch hanging baskets finish 18 weeks from sowing.

Powdery mildew is the only disease that might be a problem.