Why is starting seed under supplemental lights beneficial?

Question:

Why is starting seed under supplemental lights beneficial?

Answer:

Without adequate light, seedlings become lanky.  Tall, spindly seedlings do not transplant well into the garden.  For most homes, even the brightest windowsill does not provide enough light and the light is one-sided causing seedlings to quickly bend towards the window making them stretch even more.  By utilizing a supplemental light source, such as a fluorescent or LED fixture, you can provide enough light to produce high quality, compact, and stocky seedlings that transplant well into the garden.

Learn more about providing supplemental light for seedlings indoors in this article: Growing Indoor Plants Under Supplemental Lights.