Sow on the surface of good seed compost and gently firm them in before watering. Place in a cold frame and transplant individually into small pots when large enough to handle. Keep moist but not wet and grow on in a cool environment before hardening off and planting out in the garden. Most seeds should germinate within 6 weeks, but as they need cold and wet conditions prior to germination, some may lie dormant for up to 2 years before they start to sprout. Therefore, once the first seedlings have been thinned out and grown on, tuck the seed tray in a shady corner and see what happens.