{"id":2729,"date":"2019-08-02T00:04:17","date_gmt":"2019-08-02T07:04:17","guid":{"rendered":"https:\/\/depts.washington.edu\/hortlib\/pal\/pal-question-518\/"},"modified":"2023-08-08T12:54:06","modified_gmt":"2023-08-08T19:54:06","slug":"encouraging-orchids-to-bloom","status":"publish","type":"pal","link":"https:\/\/depts.washington.edu\/hortlib\/pal\/encouraging-orchids-to-bloom\/","title":{"rendered":"encouraging orchids to bloom"},"content":{"rendered":"

All but one of my orchids are blooming this season! What could be the cause of the one orchid not blooming?<\/strong><\/p>\n

 <\/p>\n

First of all, congratulations that you have all but one of your orchids
\nblooming. Orchids are plants with very particular needs, as you well know. I
\nhave found two possibilities as to why your one orchid will not grace you with
\nits flowers: light and space. However, there are other possibilities as well,
\nwhich I will try to address.<\/p>\n

Perhaps this one plant is not receiving the amount of sunlight it needs to bloom
\nand the others are. Are all your orchids the same species or variety? If so, are
\nthey all in the same area of your house; i.e. same window? If they are not the
\nsame species or variety, then they may require different amounts and levels of
\nintensity of light. Are they growing in a window with natural light or are you
\ngrowing them under artificial light? If you are using artificial light, orchids
\ndo require dark as well as light. Orchids “should not receive more than 14 hours
\nof artificial light a day. More than that will prevent them from blooming.”
\n(Orchid Growing Basics<\/em> by Dr. Gustav Schoser, Sterling Publishing Company, 1993)<\/p>\n

Are you using a fertilizer? If so, and the first number is a lot higher than the
\nsecond or third (such as 15-5-5), it is likely that the plant is receiving too
\nmuch nitrogen. This will do wonders for the green leaves but nothing to promote
\nflowering. A fertilizer with the numbers closer together (such as 10-12-10) will
\nbe more balanced and would be recommended. Are you monitoring the temperature?
\n“The effects of temperature changes are most clearly observable in the Cymbidium
\norchids. Flower production begins when daytime temperatures are about 68 degrees
\nand nighttime temperatures are around 50-57 degrees. Phalaenopsis schilleriana
\nand its hybrids will only bloom when the nighttime temperature is under 68
\ndegrees for at least 2-3 weeks.” (Orchid Growing Basics)<\/em><\/p>\n

Here is an excerpt from a frequently asked question and answer web page from a
\ncommercial grower: beautifulorchids.com.<\/a><\/p>\n

Q: I am growing my phalaenopsis orchid in the house but they never bloom. What can I do?<\/p>\n

A: The most common reason for any orchid not to bloom is insufficient light.
\nMove your phalaenopsis plants to a window where they will receive strong, but
\nindirect light (near a south-facing window is ideal). You might also try
\nlighting your plants with a fluorescent light fixture placed about 1-2 feet
\nabove the foliage. Give up to 12 hours of supplemental light per day.
\nPhalaenopsis will also develop flower spikes in response to a cool period of
\nabout four weeks with night temperatures of 55F. After the cool treatment, raise
\nthe night temperature back to the normal 60-65F minimum. See if these changes to
\nyour growing conditions help to stimulate your plants to bloom.<\/p>\n

Another page<\/a> on the same site more clearly defines good vs. bad light. They
\nexplain that too little light may prevent the plants from blooming. They also
\nlist specific orchids that prefer low light and those that prefer moderate to
\nhigh light.<\/p>\n

The Brooklyn Botanic Garden All-Region Guides: The Gardener’s Guide to Growing
\nOrchids<\/em> (2004) Handbook #178 has good information regarding light
\nrequirements on a variety of orchids. It is noted in this book that “light is
\nundoubtedly the most important factor in determining whether or not an orchid
\nwill flower.” The American Orchid Society’s page on “Light, the Key to Successful Blooming”<\/a> should also be helpful.<\/p>\n

Also, there is a possibility that the one orchid has outgrown its pot faster
\nthan its companions and has a need for more space (and possibly more nutrients).
\n“Most orchids usually only bloom from new growth” (Your First Orchids and How
\nto Grow Them<\/em> published by the Oregon Orchid Society, Inc 1988). “An orchid is in
\nneed of repotting when the leading pseudobulb or growth has reached the rim of
\nthe pot and there is no room for future development. (The Gardener’s Guide to
\nGrowing Orchids<\/em> by Wilma and Brian Rittershausen, David and Charles Publishers
\n2001) If you are getting new shoots but they are growing over the edge of the
\npot and breaking off, this would also be a sign for the need to repot.<\/p>\n

The Gardener’s Guide to Growing Orchids<\/em> by Wilma and Brian Rittershausen, and The
\nBrooklyn Botanic Garden All-Region Guide and Orchid Growing Basics<\/em> by Dr. Gustav
\nSchoser, offer good directions on repotting. The Schoser title even offers
\nrecipes on how to make your own potting mixes.<\/p>\n","protected":false},"excerpt":{"rendered":"

All but one of my orchids are blooming this season! What could be the cause of the one orchid not blooming?   First of all, congratulations that you have all but one of your orchids blooming. Orchids are plants with very particular needs, as you well know. I have found two possibilities as to why your one orchid will not grace you with its flowers: light and space. However, there are other possibilities as well, which I will try to…<\/p>\n

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