Angel trumpets, known botanically as Brugmansia, is a large shrub or small tree grown for its summer show of large, pendulous flowers in the shape of a gramophone speaker. Angel trumpet is a species in the nightshade family, and is related to the tobacco, potato and tomato species. According to Washington State University, when planted from fresh seed and well cared for, brugmansia can grow into a mature flowering plant in 6 to 9 months.
Sow fresh angel trumpet seeds into sterile potting soil when ambient temperatures are between 64 and 79 degrees Fahrenheit. Use plastic seed trays or nursery pots that can keep the soil moist, but release excess water through multiple drainage holes.
Bury the seed in the top layer of soil with just 1/5 inch of soil covering the seed. Press the seed down in the soil lightly to create good contact with the soil on all sides.
Water the seed and surrounding soil in until the entire pot is drenched and the excess water runs out the drainage holes. Re-cover with soil if it gets displaced when watering. Keep the soil wet at all times through germination.
Create a greenhouse effect for the seed by covering the pot with a sheet of clear plastic film or a clear glass or plastic plate. Keep the covered pot in a location with ambient temperatures hovering near 68 degrees Fahrenheit.
Allow roughly 20 days for the seed to germinate. When green shoots appear, slide the plate off the pot lip slightly, or lift the corner of plastic film to allow some fresh-air ventilation.
Allow the plants to reach maturity before they begin to flower, which should happen when they reach 3 to 5 feet in height.