Orchids are one of the largest and most diverse families of flowering plants. Successfully cultivating them in Florida requires careful attention due to the state’s unique subtropical climate, characterized by intense sun, high heat, and significant humidity. Managing these environmental factors is paramount for replicating the ideal conditions orchids thrive in naturally. Growing orchids here is less about traditional gardening and more about managing a delicate ecosystem.
Choosing the Right Orchids for Florida
Success in Florida begins with selecting warm-growing orchid genera, as the climate is inhospitable to cool-growing varieties. Genera that naturally thrive in tropical or subtropical lowlands are the most suitable choices for outdoor cultivation. Excellent choices include Cattleya orchids, known for their large, fragrant blooms, and Vanda orchids, which prefer high light and heat. Dendrobium and Phalaenopsis (Moth Orchids) also flourish if their specific light and watering needs are met.
These warm-growing varieties tolerate temperatures between 55°F and 90°F. Cool-climate orchids, which require a significant temperature drop at night, will likely fail. Florida also hosts native orchids, such as the Florida Butterfly Orchid (Encyclia tampensis), which are rewarding options for experienced hobbyists. Non-native, warm-growing hybrids are the easiest and most reliable place for a beginner to start.
Optimizing Light, Temperature, and Air Flow
Light Requirements
Florida’s intense sunlight is often too harsh for many orchid species and requires careful filtering to prevent leaf burn. Most orchids prefer bright, indirect light, achieved using a 50% to 70% shade cloth or by placing them under an open tree canopy. High-light genera like Vanda and Cattleya hybrids thrive in light levels between 2,000 and 4,000 foot-candles. Low-light plants like Phalaenopsis require closer to 1,000 to 1,500 foot-candles. Dark green leaves indicate insufficient light, while yellow or scorched leaves signal excessive intensity.
Air Movement
Managing high ambient humidity is important, as stagnant, moist air creates a breeding ground for fungal and bacterial diseases. Consistent air movement is necessary to quickly dry the leaves and flowers after watering or rain. This can be accomplished with natural breezes or by using oscillating fans to create a gentle, non-direct air current around the plants.
Temperature Management
Temperature management focuses primarily on cold protection during infrequent winter cold snaps. While most warm-growing orchids tolerate day temperatures up to 95°F, they are sensitive to sustained cold below 45°F. Cold-sensitive varieties like Vanda and Phalaenopsis should be moved to a protected area, such as a garage or enclosed lanai, when temperatures are forecast to drop below 60°F. Covering plants with breathable fabric, like sheets, can also help protect them by trapping residual warmth.
Watering and Fertilization Schedules
Watering
Proper watering in Florida’s high-humidity environment is the most common cause of orchid failure. Orchids should be watered when their potting medium is nearly dry, not on a rigid schedule. Epiphytic orchid roots have a spongy outer layer called velamen, which appears silvery-gray when dry and bright green when saturated. This color change is the most reliable visual indicator for watering needs.
Watering frequency increases significantly during the hot summer months but slows during the cooler winter. Orchids with water-storing pseudobulbs, like Cattleya, tolerate a full drying out period. Always water thoroughly, allowing water to run completely through the pot, and ensure the crown remains dry to prevent rot.
Fertilization
Fertilization is best managed using the “weekly, weakly” method, applying a highly diluted water-soluble fertilizer with every watering, typically at one-quarter the recommended strength. The NPK ratio should be chosen based on the potting medium. A high-nitrogen formula, such as 30-10-10, is preferred for bark mixes to replace nitrogen consumed during decomposition. Balanced formulas, like 20-20-20, are suitable for inert media. Many growers supplement with calcium and magnesium to address micronutrient deficiencies common in local water sources.
Potting Substrates and Mounting Options
Potting Substrates
Standard garden soil is entirely unsuitable for epiphytic orchid roots and leads to rapid root rot. Orchid roots are adapted to cling to tree bark and require constant airflow to their velamen layer. Dense soil suffocates these roots, preventing the necessary wet/dry cycle. Potted orchids require a chunky, fast-draining substrate that ensures maximum aeration. Common components include:
- Coarse fir or pine bark.
- Horticultural charcoal.
- Lava rock.
- Perlite.
Sphagnum moss is often included to retain moisture, but it should be used sparingly in high humidity to prevent the mix from staying saturated too long. Repotting should occur every one to two years, or whenever the substrate begins to decompose and impede drainage.
Mounting Options
A successful Florida technique is mounting orchids directly onto trees, which mimics their natural growth habit. Orchids should be attached to rough-barked trees, such as live oaks or palms, on a horizontal branch or the north/east side of the trunk to receive filtered sun. The old potting medium must be removed completely. Secure the plant snugly using non-abrasive material like nylon stockings or natural twine until the roots attach to the bark. Mounted orchids dry out much faster than potted ones, requiring daily misting or soaking during peak summer heat.