Lilies are summer-blooming flowers that grow from corms, which are a type of flower bulb. There are two types of hybrid lilies, according to the University of Massachusetts: Oriental and asiatic. Oriental hybrids are larger and more fragrant than their Asiatic counterparts. Hybrid lilies can be grown outdoors or in containers. Often, they are cultivated by commercial growers in containers and sold as gift plants.
Choose a container that is large enough for your lilies. Oriental lilies in particular can grow quite tall and be top-heavy. The Valley K Greenhouses website recommends planting one Oriental hybrid lily corm, or bulb, for each 1-gallon pot. Dwarf or smaller Asiatic lilies can be planted two bulbs to a 1-gallon pot. The container should have a drainage hole, as the corms of lilies are quite fragile and will rot if left to sit in overly wet soil.
Using the proper planting medium is vital for the health of lilies, according to the University of Massachusetts. Any loose, light medium will work, but it should not contain perlite or superphosphate, which can cause leaf scorch. Both types of hybrid lilies tend to thrive in sandy soil. The pH level of the planting medium, which is likely listed on the packaging, should be around 6.5.
Immerse the bulbs in a pre-planting fungicide dip for about 20 seconds before planting them. This will help prevent them from rotting. Place them in the planting medium so that they are covered by at least 2 inches of soil. Four inches is even better. Water immediately afterward to settle the soil around the bulb.
Light and Temperature
Potted lilies need cool temperatures at first in order to grow, according to the University of Massachusetts. Place the pot in a location where the temperatures are between 48 and 55 degrees F. After two or three weeks, or when a shoot develops, move the pot to a location where the temperatures are around 60 degrees. This can vary between night and day temperatures. At this point, the pot should be in a location that receives at least six hours of bright but indirect sunlight. Once buds appear, the temperatures can be raised by about 5 degrees. After the plant flowers, drop the temperature again by 5 degrees if you want the color of the blooms to be more vibrant and last longer.
Water and Maintenence
Water potted lilies when the top 2 or 3 inches of soil are dry to the touch. Use a balanced (10-10-10) water-soluble fertilizer once every other week or so in place of the watering. Cut the top 1/3 of the flower stem off when the blooms wither, but wait until the foliage turns completely yellow to cut it off at the level of the soil. Doing so will allow the nutrients to return to the bulb and be stored for next year's blooming.