Grow Light FAQ

Grow Light FAQ image by Image Courtesy of ACF Greenhouses
Grow Light FAQ image by Image Courtesy of ACF Greenhouses


The success of an indoor garden can depend on lighting. Natural sunlight is difficult to emulate, and can require different degrees light for different stages of a plant's development.


The main types of grow lights used for indoor systems are fluorescent, incandescent and high-pressure sodium.


The amount of square area that each grow light should cover is based on the wattage output. The most common wattage outputs come in sizes of 100W, 250W, 400W, 600W, and 1,000W.

Day / Night Cycle

Seedlings should be placed under continuous light until the first leaves sprout. Once the vegetative growth phase begins, revert to a more natural cycle of 18 hours in the light and six hours of darkness.

Electronic Grow Light

Electronic grow light systems provide the greatest advantages to indoor gardening. Most systems can use both a Metal Halide in the growth phase and High Pressure Sodium during flowering.

High Pressure Sodium Light

High Pressure Sodium or (HPS) lamps operate at a high lumen level, providing intense heat for budding and flowering. Sometimes called High Intensity Discharge (HID) lamps, these lights come in sizes of 2000 and 3000 degrees Kelvin.

Metal Halide Light

Metal Halide Lights put out light in the blue violet spectrum, and are primarily used for the seeding and vegetative growth phase. Metal Halides can range in temperatures from 2600 Kelvin to 7000 Kelvin.


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What started off as casual observations and daydreams are now essays, poems and stories, for Frederick S. Blackmon. His love for fiction and theater eventually led to a career writing screenplays for the film & television industry. Living in Florida, Blackmon also began exploring issues on global warming and environmental science. Now he writes everything from How-To blogs to horror films.

Photo by: Image Courtesy of ACF Greenhouses

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