Sow very thinly in trays or pots of moist seed compost (eg. John Innes), lightly cover with compost and seal inside a polythene bag. Maintain an optimum temperature of 18-21C for 8 weeks, then place the container(s) in the fridge for a further 8 weeks. Then, return to 18-21C and germination should take place. Keep out of direct sunlight.