For biggest plants, sow shallowly in Sept, protect over winter and prick out in early spring. Or sow March under cover. Or sow April outside. Or all three for sequence of bloom. Big flat lavender stars with darker lavender centres. Flowers close in afternoon. Handsome upright plants. Giant architectural dandelion seedheads. Hardy annual, self sows 18"
Water deeply and regularly (mornings are best). Avoid overhead watering. Let the soil dry completely, then thoroughly wet it.
Temperatures between 65 (18 °C) to 75 F (23 °C) and nighttime temperatures between 50 t(10°C) to 60 F (15 °C).