Fill your pots or planting cells with moistened potting soil. The ideal size is about 2-3". Eventually, you will have to "pot up" your seedlings. In other words, you will transplant them to a larger pot once they have about three sets of leaves and the roots have filled the starter pot. Although it might seem wise to start with a larger pot, it's not. Seedlings seem to do better in close quarters. 2. Place one tiny seed in each pot and cover with a thin layer of moistened soil, just enough to cover the seed. Cover the pots with a piece of plastic wrap or — if you're using a seed-starter — put the clear cover on top. 3. Place the whole setup in a place that's warm, with bright, indirect light. Geranium seeds germinate best at 75 degrees F., so consider putting them on top of a refrigerator or using a Heat Mat. If the soil surface gets dry, use a mister to moisten it with water. 4. Watch for germination, which can take as few as three days or as long as four weeks. As soon as you see the first shoots of green, remove the covering and moisten the soil if it looks dry. 5. Move the tiny plants to a place that gets bright light, with temperatures in the 70s during the day and no lower than 60 degrees F. at night. Although you can grow them on a sunny, south-facing window, grow lights are best. Keep the bulbs no more than 6" above the plants, adjusting as they grow. Leave the lights on for 12 to 16 hours a day. 6. Begin fertilization at this stage: once a week with liquid fertilizer that's mixed at half strength. 7. When the plants have three sets of leaves, transplant them to a 3-1/2" to 4" pot. Self-watering Pop Out Pots work well, but you can use anything that's about 4". "This gives the roots more room to grow," Valerie says. "Plus, you get more space between the plants, so air can circulate. Crowded plants are more susceptible to disease." Don't get thrifty by reusing old soil,