Here is more scientific data to back up plant growth at night (with references). Thanks for playing!

Biologists Identify Genes Controlling Rhythmic Plant Growth

While most people might assume that plants grow at a slow and steady rate throughout the day and night, Darwin and others found that they grow in regular nightly spurts, with plant stems elongating fastest in the hours just before dawn. See video of soybean sprout growth at: http://www.biology.ucsd.edu/scicomm/video/bigbeansprout.mov
"Plants actually grow rhythmically," said Kay. "Some plants, like sorghum, have the ability to elongate a centimeter or more each night."
Why plants have evolved mechanisms to grow rhythmically at night or in the hours just before dawn is a mystery. But a similar interplay of light sensing, plant hormones and circadian rhythms that leads to a pronounced rhythmic growth by plants during certain seasons and when shaded by other plants has a clear survival value.

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