In a strict sense, plants do not grow faster in the dark; they grow slower. However, plants seem to grow faster in insufficient light due to rapid cell elongation. In other words, they don't grow faster, they simply stretch. It is important to know that green plants really only grow as a result of photosynthetic processes. Without light photosynthesis ceases and plant tissue develop the characteristic, low-light induced sickly green or white coloration.
Rapid elongation of plant cells in low-light conditions is an emergency response on the part of the plant to return its plant tissues to the light where they can again photosynthesize and live. This would be analagous to standing on the bottom of a swimming pool and stretching to get your nose above water for a breath of life-giving oxygen.
In conditions of total darkness, plant cells will generally expand upward, a process called geotropism. In conditions where a small amount of light is reaching the plant, it will grow toward the brightest source of light in a process called heliotropism. Prolonged exposure to darkness will inevitably lead to the death of a plant.
More General Botany Questions
Are freshwater sponges poisonous if eaten by a dog? September 25, 2009 - Are freshwater sponges, native to Missouri, poisonous if eaten by a dog? view the full question and answer
Carolina wolfberry blooms but doesn't produce fruit May 10, 2012 - I have had my carolina wolfberry for 2 years now ( I got it at the Wildflower center), it seems to be doing well, creeping all over the flower bed with some branches on the ground up to 6 ft long. It ... view the full question and answer
Trillium phototropism May 16, 2010 - I'm SURE you haven't had this question before. I live in northern Michigan in a wooded subdivision where we have clouds of wild grandiflorum trilliums growing in the woods on either side of the roa... view the full question and answer
Seaweed seed dispensers in Long Island, NY January 03, 2013 - Several months ago, we found what are probably seaweed seed dispensers. They are dark brown, hard, four sharp points,section where it would have connected to the main plant and an open hole where the... view the full question and answer