Remove the flower stalk close to the top of the bulb with a sharp knife after all the blooms have faded. Do not cut the leaves or emerging flower stalks. It is normal for sap to run out of the cut flower stalk.
Move your potted amaryllis to the sunniest location available, preferably a greenhouse or south-facing window. Fertilize the plant monthly with an all-purpose liquid fertilizer. Keep the soil consistently moist, but not wet.
Move your amaryllis outside, if possible, when all danger of frost is past. Place in a sunny spot and water the plant daily. Older leaves may die, but new ones will grow. Apply a slow-release fertilizer or apply liquid fertilizer every two weeks.
Stop feeding your amaryllis in late September. Bring it indoors before the first frost. Keep the entire pot in cool storage in a garage or basement, or in a refrigerator if you have room. Do not store your amaryllis near ripening fruit, because it releases a gas that can damage developing flowers.
Begin to water your amaryllis when the new bloom stalk emerges. Water thoroughly initially, then allow the soil to dry between waterings. Blooming will take up to eight weeks. Move your amaryllis to a south-facing window until it is in full bloom, then move it to a lower-light, cooler location to preserve the bloom.