Sow indoors from February till November at 20º C, in a seedtray. Place the tray during 2-3 weeks in a dark room. Keep soil moist by spraying water with a plant spray and cover the tray with clingfilm to prevent the soil from drying out. Remove the clingfilm when the first shoots appear. As soon as the height of the plants is 8-10 cm, you need to transplant them into flowerpots.