While many plants are commonly called lilies, true lilies belonging to the Lilium genus can successfully bloom indoors. Achieving this requires specialized techniques, most often involving the process known as bulb forcing. Success depends entirely on managing the bulb’s natural life cycle and providing precise environmental controls. This temporary indoor growth allows gardeners to enjoy the characteristic large, fragrant blooms during winter or early spring.
Choosing the Right Lilies for Indoor Cultivation
The term “lily” is frequently misapplied to plants like the Peace Lily (Spathiphyllum) or the Calla Lily (Zantedeschia), which are unrelated tropical species. True lilies are herbaceous, bulbous perennials belonging to the genus Lilium and require a specific cold period to initiate flowering. When selecting bulbs for indoor forcing, it is important to choose varieties known for compact growth and reliable blooming. The most suitable types for this purpose are generally the Asiatic, Oriental, and Trumpet hybrids.
Asiatic lilies are often preferred by beginners because they require the shortest chilling period and are less sensitive to temperature fluctuations than other types. Oriental lilies, which include the highly fragrant ‘Stargazer’ variety, produce larger flowers but need a longer, colder dormancy period before they can be forced. Trumpet lilies are also viable, but their tall stature can make them cumbersome for standard indoor environments. Selecting large, firm, and healthy bulbs free from mold or soft spots is necessary.
Forcing involves planting dormant, pre-chilled bulbs into containers during the late fall or early winter months. Alternatively, pre-potted containerized varieties started by a commercial nursery offer a simpler approach. Regardless of the method, proper identification of the Lilium species ensures the grower can provide the correct environmental cues necessary for bloom induction.
Essential Environmental Setup
True lilies require bright, indirect light once the shoots emerge from the soil. A south or west-facing window that receives several hours of bright, filtered light daily is typically sufficient for good growth. Insufficient light will result in etiolation, where the stems become weak and leggy as they stretch toward the light source. If natural light is limited, supplementing with a full-spectrum LED grow light positioned close to the foliage can prevent this issue.
Optimal daytime temperatures for blooming lilies range between 60°F and 65°F, with slightly cooler temperatures at night being beneficial. Warmer indoor environments, especially those above 70°F, can accelerate the growth cycle too quickly, leading to weak stems and short-lived blooms. Placing the container near a drafty window or in a cooler basement room can help maintain these lower temperature requirements.
The planting medium must be highly porous and well-draining to prevent the bulbs from rotting. A suitable soil mixture can be created by combining standard, peat-based potting soil with amendments like perlite, coarse sand, or bark fines at a ratio of about 3:1. Lilies prefer a slightly acidic to neutral pH range, typically between 6.0 and 6.8, which standard potting mixes usually provide. The container itself should be deep enough to accommodate the bulb and its developing root system, generally at least 6 to 8 inches deep.
Watering Schedules and Nutrient Needs
During the active growth phase, from the emergence of the sprout until the flowers fade, the soil should be kept consistently moist but never waterlogged. Overwatering is a common cause of bulb rot and must be avoided by ensuring the container has excellent drainage holes. Checking the moisture level by inserting a finger about an inch into the soil is the most reliable method before adding water. The frequency of watering will increase as the plant grows larger and the ambient temperature rises.
Lilies are not heavy feeders, but they benefit from supplemental nutrition once the stem reaches approximately six inches in height. A balanced, water-soluble fertilizer, such as a 10-10-10 or a formulation slightly higher in potassium, should be applied every two to four weeks. Diluting the fertilizer to half the strength recommended on the product label helps prevent the accumulation of salts in the potting medium. Fertilization should cease entirely immediately after the flowering period concludes.
Once the blooms have finished, the watering schedule must be significantly reduced to prepare the bulb for its necessary rest period. Allowing the top inch or two of the soil to dry out between waterings signals the plant to begin transferring energy back into the bulb. This transitions the plant toward dormancy.
Handling Post-Bloom Dormancy and Troubleshooting
After the flowering is complete, the foliage should be allowed to naturally yellow and die back, which can take several weeks. It is important not to cut the stem until the leaves are fully brown, as this foliage continues to photosynthesize and store energy in the bulb for the next cycle. Once the stem is completely withered, it can be cut back to just above the soil level. The container should then be moved to a cool, dark location, such as an unheated basement or garage, where temperatures remain above freezing but below 45°F.
This required chilling period typically lasts between 10 to 12 weeks for most Asiatic and Oriental varieties. During this time, the bulb should be kept relatively dry, receiving only occasional, minimal water to prevent complete desiccation. Following the chilling period, the bulb can be brought back into warmer conditions to re-initiate the forcing process.
A common issue is the failure to bloom or bud blast, which is often caused by insufficient light during the growth phase or inadequate chilling during the dormancy period. Indoor pests, particularly aphids and spider mites, can also affect lilies, especially in dry, warm environments. Treating these pests quickly with insecticidal soap or neem oil is usually effective.