Cattleya Orchid Care Guide for New Zealand Growers

Cattleya Elizabeth Calov ‘Spottyvale’, HCC/NZOS

Cattleya Lindy-Lou 'Kumeu', HCC/NZOS

Rhyncattleanthe Life's Charm 'Redvale', HCC/NZOS

Rhyncattleanthe Bright Spark 'Luscious'

As epiphytes in their natural habitat, Cattleya orchids have evolved fascinating adaptations, including water-storage organs called pseudobulbs and large, fleshy roots covered with a spongy, water-absorbing velamen. This natural design means they're accustomed to periods of dryness between waterings and require exceptionally well-draining growing media.

1. Light Requirements for Cattleya Orchids

Light stands as the most critical factor in successfully growing and flowering your Cattleya orchid, whether you're cultivating them in a greenhouse or an indoor environment. Cattleya orchids thrive with bright light to some direct sunlight, but require protection from intense midday sun.

• For indoor growing, position your Cattleya orchid near an east-facing window, a south-facing window with sheer curtain protection, or a west-facing window.
• For greenhouse cultivation, provide 50 to 70 per cent of full sunlight exposure, equivalent to 3,000 to 5,000 foot-candles (32,000 to 54,000 lux).
• Proper lighting is evident when leaves display a healthy medium-green colour and pseudobulbs remain erect without requiring support stakes.

2. Temperature Management

A. Day and Night Temperature Ranges

Cattleya orchids require specific temperature ranges for optimal growth:

• Night temperatures: 13-16°C 
•  Day temperatures: 21-29°C
• Seedling requirements: Night temperatures should be 3-6°C higher than mature plants.

B. Seasonal Temperature Considerations

A temperature differential of 8-11°C between day and night proves essential, particularly for mature plants. During New Zealand's warmer months (December through February), day temperatures up to 35°C can be tolerated provided you increase humidity levels, improve air circulation, and provide adequate shading.

3. Water Requirements

A. Container Watering

Watering your Cattleya orchid requires careful attention to multiple factors, including container size and type, ambient temperature, and light conditions. The fundamental rule for mature cattleyas is allowing complete drying between waterings, while seedlings require more consistent moisture levels.

A practical method involves comparing the weight of your planted pot with an identical dry pot containing the same growing medium. A light pot indicates dry conditions requiring water, while a heavy pot suggests adequate moisture remains.

B. Watering Guidelines

When uncertain about watering timing, err on the side of caution and wait an additional day or two. Plants in active growth phases require more frequent watering compared to resting periods. Avoid using water below 10°C, as this can damage your orchid, and never use salt-softened water.

C. Seasonal Watering Adjustments

During New Zealand's growing season (September through March), increase watering frequency to support active growth. Reduce watering during the cooler months (April through August) when plants enter their resting phase.

4. Humidity Control

Cattleya orchids flourish with humidity levels between 50-80 per cent. For home growers, achieve appropriate humidity by placing plants on gravel trays partially filled with water, ensuring the pots never sit directly in standing water.

Continuous air movement around your plants remains crucial for preventing fungal and bacterial diseases, especially important during high humidity conditions or cooler weather periods. In greenhouse environments, dedicated humidifiers provide the most effective humidity control, while evaporative cooling systems offer the dual benefit of increased humidity and temperature reduction.

5. Fertiliser Program

A. Fertiliser Selection

Establish a regular fertilising schedule for optimal Cattleya orchid health. Use a balanced fertiliser formulation such as Superthrive (Dyna-Gro) Orchid-Pro, or Superthrive (Dyna-Gro) GROW or similar proportions.

B. Application Schedule

Apply fertiliser every week. All Superthrive fertilisers should be diluted using 1 mL of fertiliser for 1.5 litres of water. Ensure that you pour enough of the fertiliser solution into the potting mix so that all of the potting mix is moistened by the solution.

C. Important Fertilising Practice

Perform thorough monthly flushing with clear water to prevent harmful fertiliser salt accumulation in the growing medium.

6. Potting Requirements

A. When to Repot

Repotting becomes necessary when the rhizome extends beyond the pot edge or when the growing medium begins decomposing or draining poorly, typically occurring every 2-3 years. Optimal repotting timing occurs just before new root emergence from the rhizome, usually after flowering or during New Zealand's spring season (September-November).

B. Potting Specifications

• We recommend using Kiwi Orchid Bark or Bio Leaf Orchid Potting Mix.
• Avoid dividing plants until they possess at least six mature pseudobulbs; instead, transfer to larger containers.
• When division becomes necessary, ensure each division contains 3-5 pseudobulbs.

C. Repotting Process

• Select containers allowing for approximately two years of growth before overcrowding occurs.
• Position the growing medium against one pot side, remove dead roots, and spread healthy, firm roots over the medium pile with the cut rhizome against the pot side.
• Fill with growing medium, working it thoroughly around roots, pack firmly, and stake if required.
• Maintain humid, shaded conditions with dry roots until new root growth appears.

Summary

Successfully growing Cattleya orchids in New Zealand requires attention to six fundamental care aspects: providing bright, filtered light; maintaining proper temperature differentials between day and night; allowing thorough drying between waterings; sustaining 50-80% humidity with good air circulation; following regular fertilising schedules; and repotting every 2-3 years with appropriate timing.

These magnificent epiphytic orchids reward proper care with spectacular blooms and robust growth. By understanding their natural adaptations and adjusting care routines to New Zealand's seasonal patterns, you'll enjoy years of successful Cattleya orchid cultivation. Remember that these resilient plants prefer to dry out between waterings and thrive with consistent care rather than constant attention.

 

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