Many annual flowers and some perennials are started from seed, then later transplanted out to the garden. Germinating the seeds indoors and later planting the flowers outdoors allows you to grow just the amount of flowers you need to complete your garden plan. Germination requirements vary by plant variety, but there are general considerations that apply to most flowers. When in doubt, check the seed packet and verify the specific needs for the particular seed.
Perform any pre-treatment indicated for the seed variety. Soak seeds overnight in warm water or scuff the seed coating with a metal file if scarification is indicated. Store seeds in a plastic bag in the refrigerator for the recommended length of time prior to planting if cold-stratification is required. These processes signal to the seed that it is time to sprout.
Fill seedling pots or trays with a well-draining, sterile potting mix. Leave a ½ inch space between the soil and the pot or tray rim.
Sow seeds on the soil surface, planting two seeds per pot or spacing the seeds 2 inches apart in trays. Cover the seeds with soil to a depth twice their width. If the seed packet indicates light is necessary for germination, do not cover the seeds.
Fill a tray with water and set the pots or seed-tray inside it. Leave them to soak until the soil surface becomes moist, then empty the excess water from the tray. Bottom watering doesn't disturb the newly planted flower seeds.
Cover the pots or tray with a plastic bag, which helps the moisture stay in the soil during the germination process. Place the pots in a 65 to 75 degree F room unless a different temperature is recommended on the seed packet. Only place the pots in sunlight if it is indicated as necessary for the particular flower seed.
Remove the plastic bag once the seeds germinate and sprouts appear. Move the pots to a warm, sunny windowsill and water as necessary to keep the soil moist.