Phalaenopsis (windowsill) trial 2024–2025
Objectives and purpose of the trial
Plants and location
What was planted?
Where is it planted?
Along with the home setting provided by volunteers, full sets of orchid plants are being trialled in The Orchid House and back office at RHS Wisley, Surrey and RHS Bridgewater, Greater Manchester, for data recording and comparison. Here are some considerations for growing moth orchids:
- Moth orchids have been widely bred to produce many free-flowering and easy-to-grow hybrids
- Grow in very loose, airy compost, mainly made of composted bark
- Keeping the roots in good condition, not too wet or too dry, is the key to success with moth orchids
Judges and criteria
Judges of the trial
Judging criteria
The following factors are all taken into consideration as part of the judging of the trial:
- Healthy leaves
- Strong and long-lasting flower spikes that branch evenly
- Lots of flowers, evenly arranged
- Good size flowers with stable colour
- Ease of re-flowering and quality of new flower spikes
Cultivation
Planting process
The moth orchids were supplied by Double H Nurseries who grow the plants on over time, starting from smaller plug plants. When they were delivered to the RHS in April 2024, they were at a similar stage to shop bought plants with the larger plants in 12cm pots and the smaller ones in 9cm pots.
Once the orchids were at a stage to begin the trial, an orchid was given to each volunteer to take home and care for. The RHS Trials team provided the volunteers with a grower’s guide to help look after the orchid with the following suggestions:
- Keep the orchid in the transparent plastic pot it arrived in. Phalaenopsis only need repotting every two years or so, to refresh the bark compost
- Position the orchid in bright light. An east or west-facing windowsill is ideal. Keep it out of direct sun, as this can scorch the leaves
- Moth orchids prefer consistently warm conditions all year round, 19–30°C during the day and 16–19°C at night
- Water once weekly throughout the growing season
- Feed lightly but regularly using a specific orchid fertiliser
How we’re managing plant health
How to grow moth orchids
Explore all the information you need to know to grow and care for moth orchids at home
Suppliers to the trial
List of plants in the trial
Handy tools and information
- Full article - Filter for AGM plants and refine by colour, height and season of interest
Find an AGM plant online
Filter for AGM plants and refine by colour, height and season of interest - Full article - Explore advice and helpful tips from our resident experts
Gardening advice
Explore advice and helpful tips from our resident experts - Full article - Check how hardy plants are using the RHS hardiness ratings system
Hardiness ratings
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RHS Grow app
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Get in touch
For more information on our RHS Plant Trials or to access older trial reports, please get in touch with our team via email at [email protected].
Get involved
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