Cattleya

Light is the most important factor in growing and flowering Cattleyas, whether in a greenhouse Light is the most important factor in growing and flowering Cattleyas, whether in a greenhouse or in the home. Leaves should be a chartreuse-green color; pseudobulbs erect and require no staking.

o   In a greenhouse, 20%-35% full sun (65%-80% shade) or about 21,530-37,700 lux (2,000-3,500 footcandles) is ideal. Southern climates below the 37th parallel will require the use of shade cloth. Northern growers may be able to acclimate some species to full sun with no consequence.

o   Indoors, cattleyas should be placed in any window (ideally south-facing) that gets more than 4 hours of direct sunlight to bloom.

o   If grown under lights, cattleyas should receive more than 3000 lumens of light to bloom and grow.

Generally speaking, cattleyas need a 10F-15F (5.55C-8.3C) drop in night temperature to grow and flower well. Temperature depends on the hybrid/species, but in general, cattleyas are happy with 55F-72F (12.7C-22.2C) nights and 70F-85F (21.1C-29.4C) days. Seedlings should have night temperatures a few degrees higher. Higher day temperatures can be tolerated (up to 95F (35C) if humidity, water, air circulation, and shading are increased.

o   If growing indoors, there is no need to worry about temperature; room temperature is fine, although plants should be provided a 10F-15F (5.55C-) difference between day and night temperatures.

When thinking about water for epiphytes like cattleyas, you must keep in mind that they like to have quick wet/dry cycles. Cattleyas like to go dry between waterings but like to be immediately watered when their media hits dryness. Always use lukewarm water, as water temperature below 50F (10C) may injure plants, as will hardwater or water softened by the addition of sodium chloride.

o   If growing in a greenhouse, you should adjust your watering so that the plants have time to dry before the next watering. Mounted cattleyas may require additional watering in warm/hot conditions.

o   Indoors, cattleyas should be grown potted and watered from the top. Otherwise, they can be taken to the shower or sink, watered, allowed to drain, then be placed back. The frequency will depend on how long it takes for the medium to dry in your conditions.

Most orchids grow best in a relative daytime humidity of about 40 to 70 percent. Humidity is moisture in the air, not water on the plants or in the growing medium. Airborne moisture keeps plants from drying out in bright light and warm, dry air without encouraging fungi and bacteria that can infect wet plants.

o   In a greenhouse, air should always be moving around the plants to prevent fungal or bacterial disease, especially if high humidity or cool temperatures exist.

o   Indoors, as long as cattleyas are thoroughly and frequently watered, you do not need to worry about humidity.

Fertilize on a regular schedule. Use ½ to ¼ strength of a normal dose regularly when plants are actively growing. A higher nitrogen formulation (such as 30-10-10) is recommended during active growth. In autumn, or after growth slows, fertilizer should be reduced or eliminated for the winter. Some growers use a high-phosphorus formula in the spring to promote flowering.

Potting is necessary when you first get the plant, if the rhizome of the plant protrudes over the edge of the pot, or if the potting medium starts to break down and drains poorly (usually after 2 to 3 years). If you see new roots or shoots just starting to grow, that is the best time to repot. Otherwise, you will have to wait until after flowering. Mature cattleyas are usually potted in coarser potting material than are seedlings. Select a pot that will allow for approximately two years of growth (usually a 2-3 inch (5–8 cm) larger diameter pot) before crowding the pot.

Until a plant has at least six mature pseudobulbs, it generally should be repotted into a larger pot and not divided. If dividing a plant, three to five pseudobulbs per division are required to avoid an interruption in flowering.

o   If growing in a greenhouse, use a medium to coarse orchid bark mix. No sphagnum is necessary, except for perhaps the smallest of seedlings.

o   If growing indoors, you will want to mix about 25% to 33% of sphagnum to either fine or medium grade orchid bark mix (which is bark+perlite+charcoal). Alternatively, using 100% treefern fiber works well with plastic pots indoors.

Cattleyas usually bloom once a year, though through hybridization, some hybrids can bloom multiple times a year. Many are fragrant, unless there are laelias, former Sophronitis species, or some Guarianthe species in the background.

• Cattleyas for the Beginner

Further information can be found on the Cattleya genus page.

Best orchid care practices are also provided for watering, repotting, and fertilizer types. There are also detailed discussions of growing orchids indoors, outdoors, or in greenhouses.

For more information on genus name changes, see Taxonomy.