Do Plants Grow Faster in Light or Dark?

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The way light conditions can influence plant growth need not be overwhelming, as the concept is relatively straight forward. Understanding light influence is essential knowledge for the beginning gardener or botanist.

Plant Growth in Darkness

Plants grow fast in the dark, and do so because they operate on circadian cycles. According to, university research revealed that plants exhibit growth in predawn hours, and cease growth in daylight. In simplistic terms, it makes sense that plants would grow at night since daylight activity consists of absorbing light for photosynthesis.

Varieties of Darkness

Plants are embodied with phytochromes — detectors that tell the difference between nightfall, a cloudy day and being overshadowed by other plants — thus, all low-light conditions are not the same to a plant. In 2008, revealed that tall spindly plants are a byproduct of “Shade Avoidance Syndrome,” a scientific term for a plant's tendency to increase its production of the growth hormone auxin, allowing the plant to grow and stretch more rapidly toward sunlight to improve its conditions.

Shade Loving Plants

Too much sun is detrimental to certain plant species. Biology Online's "Lights' Effect on Growth," noted that the amount of time a plant needs to spend in the light is known as its "critical period." Shade loving plants would typically be those found in a forest or jungle where conditions are darker due to canopy plants allowing dappled or minuscule amounts of sunlight to reach the smaller plants, meaning they are not entirely deprived of light but have adapted to prosper in their low-light conditions.

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