Grow and flower your Slipper Orchids (Paphiopedilum Orchids / Pahps. / Phragmipediums / Phrags.) successfully by following these simple tips.
How to grow Slipper Orchids in summary – use the smallest pots which the roots will fit in and position in bright light but no sun.
LIGHT – With the aid of minerals taken up by the roots, light absorbed from the sun, and carbon dioxide from the air, green leaves produce energy to grow and flower. This process is called photosynthesis, “Paphs” require a much lower light intensity than cattleyas, dendrobiums or cymbidiums for this to occur at an optimum level. An easy light test is to move your hand about 50cm above the foliage on a sunny day. If a noticeable shadow is cast on the leaves, apply more shade.
Most people who say they don’t have 'much luck with slippers' keep them either too bright or grow them in pots too large. When growing outdoors, shade cloth with a density of 90 % is recommended or better still, three layers of 70% so that one layer can be removed in late Autumn and added again at the end of Winter. For indoor growing, bright light but no sun (weather direct or filtered) is best. Paph leaves should always be a lush green.
POTTING – It is worth remembering that most Paphs die from over-potting. The smallest pot possible should be used to comfortably fit the roots. Overly long roots are best ‘spiralled’ into the pot by turning the pot until the roots are wound in. Frequent potting is beneficial but no more than twice a year, however healthy and mature plants can confidently be left in the same pot for two years. Suitable materials for potting include bark, coconut chips, perlite, polystyrene, shell grit, and gravel. Particle size should not exceed 15 mm of any ingredient. I like the bark component to be at least 50% of the volume with some coconut chips for extra water holding. It is important for the mix to be moist but never wet when potting.
TEMPERATURE – The optimum temperature for most Paphs is around 26°C during the day and relative humidity of around 50% – 60%. Paphs are however, quite tolerant to extremes. Even 40°C and just short of freezing for short periods will do no harm, but prolonged extremes will slow down growth and eventually kill. Draughts or strong winds, especially on hot days will desecrate the leaves. Air movement or fans are not required.
WATERING – If you only have a few plants, stand the pots in the sink or a container overnight with the water level about half way up the pots, once a week. This will give them an even soaking. Rain water is preferable, fertilizer can be added. Pot plants should always be given a good soaking when dry, rather than small amounts often.
FERTILIZER – Most fertilizer brands including fish and seaweed products for indoor plants are suitable if used at a quarter to half recommended strength about once every third watering and less frequently during Winter and extremely hot weather.
Do you have sick plants?
If you have a sick slipper orchid or one that doesn’t thrive and would like a free diagnosis I am available at any shows in the afternoon (when I’m not so busy) for advice. Just bring your orchid plant in.