Sow your geranium seeds in moist, free-draining seed compost in a seed tray or small pot. Space the seeds out so that each has space to germinate, and cover with a thin layer of compost or vermiculite. Water gently after sowing with a fine rose or mist spray. Propagate with lid or plastic wrap. Remove once germinated. It's essential that a steady and warm soil temperature of between 70-75F (21-24C) is maintained to germinate geranium seeds.
Sow seed in October when ambient temperatures are still fairly high. Grow your young plants through the winter and spring, keeping them at around 45F (7C). Autumn sowing saves on fuel compared with January sowing, and produces earlier flowering and healthier plants.
Or, sow your geranium seeds from mid to late December for flowering in late April and early May. Alternatively, an early January sowing should produce flowers in mid to late May.