How to Use Grow Lamps


Using grow lights makes it possible to grow plants indoors year-round. They can be used to supplement natural light or provide complete lighting for low- to medium-light plants. Grow lights are specially designed to provide light in the wavelengths needed by plants for optimum growth. Plants need high-quality light at a high-intensity and for a sufficient length of time for healthy growth.

Step 1

Locate your growing plants near a source of natural light if possible. Even a small amount of sunlight is a helpful supplement to the light provided by grow lamps.

Step 2

Attach the grow light fixture above the plants with chains so that the lights can be raised or lowered as needed. Adjust the lights so that they are 6 to 8 inches above the plants.

Step 3

Check the heat level at the top of the plants by holding your hand just above the plants. Move the lights up if the lights are too hot.

Step 4

Water the plants regularly. Plants under hot lamps will need more water. Check the soil moisture daily and water as needed to keep the soil moist.

Step 5

Adjust the lights upward as the plants grow, keeping the light 6 to 8 inches above the plants.

Step 6

Group the plants as they grow, so that plants of similar heights are grouped together. Raise shorter plants by placing them on risers to bring the tops of the plants to the same height.

Step 7

Keep the lights on for approximately 18 hours each day. Use a timer, if possible, to turn the lights on and off at the same time daily. Cut the lights back to 12 hours daily when fruiting or flowering is desired.

Step 8

Watch for signs of too little light. One obvious sign of too little light is tall, spindly plants with small leaves and little vegetation. Light green or yellowing leaves can also be a sign of light deprivation. Move plants with these symptoms closer to the center of the light. Lower the light, if possible without burning the plants.

Step 9

Use a fan or air conditioner to cool the space when multiple lights are used. Keep the temperature between 70 and 80 degrees F.

Things You'll Need

  • Grow light
  • Chains


  • University of Vermont Extension: Indoor Lighting for Plants
  • University of Missouri Extension: Lighting Indoor Houseplants
  • University of Hawaii: Growing Plants Indoors Under Supplemental Lighting
Keywords: use grow lamps, plant grow lights, using grow lights

About this Author

Diane Watkins has been writing since 1984, with experience in newspaper, newsletter and web content. She writes two electronic newsletters and content around the web. Watkins has a Bachelor of Science degree in chemistry from Clemson University. She has taken graduate courses in biochemistry and education.