Agapanthus is a perennial plant that is cherished by gardeners for its big, showy funnel-shaped flowers that bloom in white, blue or violet blue. Gardeners also appreciate the fact that this attractive plant is easy to grow. It just needs a bit of shelter, water, full sun and well-drained soil to grow happily. However, agapanthus is strictly a warm weather plant and should only be grown outside in USDA growing zones 8 to 11.
Prepare the seed bed at least six months before planting your agapanthus seeds. Spread a 2-inch layer of compost over the soil. Then loosen the soil with a hoe to a depth of 1 foot, mixing in the compost as you go.
Take the soil's temperature. Beginning in spring, take a thermometer and stick it 4 inches into the soil every morning at 8 a.m. Record the daily temperature. Once the 10-day average soil temperature is above 70 degrees
Fahrenheit, your agapanthus seed can be planted.
Plant the seeds by sprinkling them on top of the soil. Keep in mind that sprinkling is not an exact science. Try to give your agapanthus seeds a half inch of space or so, but don't worry too much about placement at this time. You can thin the agapanthus seedlings once they establish themselves.
Cover the seeds with a quarter inch of soil.
Gently water the seed bed so that the soil beneath the seeds is moist, not wet. Continue to keep the soil moist at this depth until the agapanthus seeds germinate. This can take anywhere from three weeks to three months, depending on the temperature of the soil and the freshness of the seed.