Hostas, known for their lush foliage and shade tolerance, are common outdoor garden plants. Many wonder if these attractive perennials can also thrive indoors, especially in colder climates. While primarily outdoor plants, hostas can be grown indoors, though it requires specific care to replicate their natural environment.
Growing Hostas Indoors
Cultivating hostas indoors presents unique challenges compared to outdoor growth. They are not typical houseplants but outdoor perennials requiring specific conditions, including a crucial dormancy period. Indoor cultivation is often undertaken for overwintering container-grown hostas, protecting them from harsh winter conditions, or for enjoying miniature varieties as temporary houseplants. Attempting to grow large hosta varieties indoors is not recommended due to their size and the difficulty in moving them.
Growing hostas indoors means you are essentially “borrowing” them for a while, rather than establishing them as permanent indoor flora. They generally should not remain indoors for extended periods, ideally no more than three to four weeks at a time for temporary display. The main difficulty lies in replicating their natural light, temperature fluctuations, and the dormancy period required for long-term health. Precise management, especially for smaller specimens, is key.
Key Care Requirements for Indoor Hostas
Successful indoor hosta cultivation requires specific environmental conditions.
For light, hostas prefer bright, indirect sunlight, such as that from an east or north-facing window. Direct sun exposure should be avoided as it can scorch their delicate leaves. If natural light is insufficient, supplemental grow lights for 12-14 hours daily can mimic their preferred outdoor light conditions.
Maintaining proper moisture is important; hostas prefer consistently moist, but not soggy, soil. Water when the top inch of soil feels slightly dry, ensuring complete drainage to prevent root rot. A well-draining potting mix, rich in organic matter like peat moss or compost, is ideal.
Average room temperatures between 60-75°F (15-24°C) are suitable during their active growing season. While hostas are not overly sensitive to humidity outdoors, indoors they benefit from moderate to high humidity (50-60%), which can be achieved with a humidifier or by placing the pot on a pebble tray with water. During the growing season, from spring to early fall, fertilize monthly with a balanced, water-soluble fertilizer diluted to half strength.
Inducing and Managing Dormancy
A primary aspect of indoor hosta care, distinguishing them from many other houseplants, is their need for a dormant period. Hostas are deciduous perennials that naturally die back in winter, requiring a chilling period to recharge for the next growing season. Without this dormancy, the plant will weaken and decline.
To induce dormancy, typically in late fall (around October), begin by reducing watering and ceasing fertilization. Allow the foliage to naturally yellow and die back. Once the leaves have withered, cut them back to about an inch from the soil line.
The plant should then be moved to a cool, dark location where temperatures remain consistently cool, ideally around 35-45°F (2-7°C), but never freezing. This cool period should last for at least 6 to 12 weeks to provide the necessary chilling hours. During dormancy, water lightly about once a month to prevent the soil from becoming bone dry.
Troubleshooting Indoor Hosta Issues
Despite diligent care, indoor hostas may encounter some common problems. Yellowing leaves can indicate several issues; too much direct sunlight, which scorches the foliage, or improper watering (both overwatering and underwatering) are frequent causes. Overwatering often leads to entire leaves turning yellow and drooping, while underwatering can cause leaves to dry and turn brown, starting at the tips. Nutrient deficiencies can also cause yellowing, sometimes appearing as yellow leaves with green veins if nitrogen is lacking.
Pest infestations, such as spider mites and mealybugs, can also affect indoor hostas, often thriving in dry indoor conditions. Spider mites, which prefer low humidity, can be managed by increasing humidity around the plant and applying horticultural oil or insecticidal soap. Mealybugs appear as small, white, cottony masses and can be treated by dabbing them with a cotton swab dipped in rubbing alcohol or by using insecticidal soap.
If a hosta fails to go dormant or emerge from dormancy, it typically signals that the chilling requirements were not met, which can weaken the plant over time.