- Sow indoors, February-April. A warm kitchen windowsill is all you need for starting these seeds.
- Sow 0.5 cm (0.2′) deep, in trays of compost.
- Water well and place in a warm position.
- A temperature of 15-20°C (60-68°F) is ideal. Keep moist. Seedlings usually appear in 14-28 days. Transplant them, 5cm (2′) apart, to other trays when large enough to handle (always hold by a leaf, never by the stem).
- Grow on in cooler, but not cold conditions. Gradually accustom young plants to outside conditions (avoid frosts), before planting out, May-June, 30cm (12′) apart, into well-drained soil, when frosts are over.
- Flowers: July-October.
- After frost blackens plants, lift tubers, allow to dry, then store frost-free. Replant the following spring, for further summer displays.