Amaryllis seeds have the best germination rates when collected fresh and planted immediately. Amaryllis belladonna flowers produce seeds that are ready to collect four to five weeks after the flowers open and are pollinated. As the flowers begin to fade, look for the developing seed pods. Wait to collect the seeds until the seed pods turn yellow in color and crack open slightly. Be careful not to wait too long or the seed pods will open and be scattered by the wind.
In mild, frost-free climates where winters are damp, plant amaryllis belladonna seeds outdoors in a garden bed. Prepare a seed bed by turning over the soil and adding compost and other organic mater. Once mixed in, the compost increases the nutrient levels of the soil making further fertilizing unnecessary during germination and the initial growth stages. Amaryllis flowers readily self propagate from scattered seeds in mild, Mediterranean and sub-tropical climates so if the climate is conducive, starting the seeds requires little additional effort.
In cold, temperate climates where winters often experience frosts, amaryllis seeds are started indoors. Start the seeds within a week or two of collecting to make sure they are fresh and retain their viability. Use a seed-starting flat filled with seed-starting compost. Scatter the seeds over the compost and cover them with a quarter inch of soil. Seeds germinate best when kept between 68 and 80 degrees Fahrenheit. Heating pads, sold at home and garden stores, can help keep the soil temperature at the right level.
Amaryllis belladonna seeds take two to three weeks to germinate. In their native range, amaryllis seeds scatter naturally just before the winter rains come. In cultivation, the seeds should be kept damp until they germinate and during the early growth stages. In the first few years after seed germination, amaryllis belladonna plants produce only leaves. One of the disadvantages of starting these plants from seed is that it takes three to six years for the plants to flower.