How to Use CFL as Grow Lights

Compact fluorescent lights (CFLs) are ideal grow lights for plants. CFLs use less energy and last long -- about 10,000 hours compared to 1,000 hours for incandescent bulbs, according to the University of Vermont. CFLs also release less heat so the indoor plants can be placed closer to the lights. A combination of cool and warm CFLs can be used to light indoor plants so the plants get a good combination of both red and blue light rays. The amount of light given off is measured in foot-candles. Be sure to know how many foot-candles the plants you want to grow need.

Things You'll Need

• Warm 40-watt CFL tubes
• Cool 40-watt CFL tubes
• CFL light fixture

Instructions

1. Place the cool CFLs and warm CFLs into the CFL light fixture. The ratio for each type of tube should be 1:1.

2. Plug in the CFL light fixture.

3. Place the plants below the light fixture at the proper distance away. Set low-light plants (those between 50 and 250 foot-candles), 1 to 3 feet beneath 2 CFLs. Set medium-light plants (those between 250 and 500 foot-candles), 1 foot beneath 2 CFLs. Set high light plants (above 1,000 foot-candles), 6 inches below 4 CFLs.

4. Provide 16 to 18 hours of light from the CFLs to the plants each day, if they receive no additional light. If they plants also receive outdoor light, only use the CFLs for 12 to 14 hours a day.

References

• University of Vermont: INDOOR LIGHTING FOR PLANTS
• University of Hawaii at Manoa: Growing plants indoors under supplemental lighting
• University of Missiouri: Lighting Indoor Houseplants