Stenoglottis longifolia is one of the more easily grown species of terrestrial orchids. They can be grown as pot plants or in gardens in areas with cool Mediterranean or warm temperate climates. These plants grow in spring and summer (October to February), flower in autumn and winter (February to July) and are dormant during the winter. The lilac flowers open sequentially from the bottom of the spike upwards, providing several weeks of blooms. With proper care, plants may multiply to form large clumps over time. While not as showy as some epiphytic orchids, its ease of care and beautiful autumn flowers make it a rewarding plant to grow.

Propagate S. longifolia plants using tubers. Propagation using seeds is not recommended, due to the challenge of artificially pollinating the small flowers and collecting and planting the microscopic seeds. Plant tubers in spring or early summer in a light, well-aerated growing medium with very good drainage. There are several suitable options for potting mix. A regular potting mix loosened with sand and small pieces of pumice works well, mimicking the plant’s natural lithophytic (growing on rock) habitat. Alternatively, use six parts medium river sand, two parts compost and one part peat moss, or a mixture of nine parts shredded bark and one part medium river sand. Plant tubers about 2 cm deep, ensuring the growing point is just below the soil surface.

Grow S. longifolia plants in areas with dappled sunlight or bright, indirect light. Avoid full sun exposure, which can damage the plants. In colder climates, plant in sheltered areas or grow in a pot that can be moved to protected spots during freezing weather. Stenoglottis longifolia grows optimally at temperatures between 20 and 35°C in summer and 6 to 22°C in winter.

Water plants regularly during the growing season (spring and summer) by thoroughly drenching the soil. Adjust watering according to local conditions. Once the leaves start to turn yellow, stop watering and feeding as the plant enters dormancy. During the dormant period, moisten the soil every two to three weeks to prevent the tuber from dehydrating. Store potted tubers in a cool, dry place with temperatures between 10 and 15°C. They can be left in the ground in suitable conditions but if grown in the ground in areas with wet winters, consider lifting the tubers and storing them in slightly damp peat moss or vermiculite to prevent rotting. Check occasionally for signs of fungal growth or rot, removing any affected tubers promptly. Gradually increase watering as spring approaches and move plants to a brighter location to encourage new growth.

Feed plants with a slow-release fertilizer when potting and again every spring. Additionally, during the growing season, fertilize every two to three weeks with half-strength organic fertilizer such as Nitrosol or Seagro. Alternate these with a 3:2:1 fertilizer at a strength of one teaspoon to 5 litres of water. Stenoglottis longifolia is not particularly demanding in terms of nutrients.

While S. longifolia is generally resilient to pests when grown in the correct conditions, it can be susceptible to several pests and diseases common to terrestrial orchids. Aphids may infest young growth and flower spikes, particularly in spring and autumn. Control these by washing them off with a strong jet of water or, in severe cases, using an appropriate insecticidal soap. Snails and slugs can damage new growth and flowers, especially in damp conditions. Regularly inspect plants and manually remove them or use organic pellets or copper tape around pots to provide protection. Fungal diseases such as root rot can occur if the growing medium is kept too wet, particularly during the dormant period. Ensure good drainage and avoid overwatering to prevent this issue. If rot is suspected, carefully remove the plant from its pot, trim away any affected parts with sterilised tools, and repot in fresh, well-draining medium. Mealybugs might occasionally appear, hiding in leaf axils or under old leaf sheaths. Remove these with a cotton swab dipped in rubbing alcohol. Spider mites can be a problem, especially if the plants are kept in overly dry conditions. Increase humidity and use insecticidal soap if an infestation occurs. As with most orchids, virus infections can occur, often manifesting as streaked or mottled leaves. There is no cure for viral infections. Isolate or discard affected plants to prevent spread. Regular inspection of plants, good hygiene practices and maintaining optimal growing conditions are key to preventing and managing these potential issues.