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Old October 5, 2018   #21
carolyn137
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Join Date: Jan 2006
Location: Upstate NY, zone 4b/5a
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Quote:
Originally Posted by LDiane View Post
I just hauled out an old book I haven't read for many years - The Edible Indoor Garden by Peggy Hardigree, St Martin's Press, New York, 1980.

Lots of information on tomatoes, but I'll just copy a bit about light.

Experiments from 1957: Even though the tomato is day-neutral and can blossom in a wide range of day-lengths, it produces more flowers with 9 hours of light. Those plants flowered 10 to 14 days sooner than plants given 16 hours of light.

Unless the plants are given at least 7 hours of uninterrupted darkness each night, they won't bloom.
And the reason the plants must have a dark phase is b/c the structures that make up a plant are made in the daytime via photosynthesis and then the dark phase is when those components are assembled.

http://www.tomatoville.com/showthread.php?t=17126

Carolyn
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