Fluorescent lights make a good light supplement where sunlight is not available, but they can never supply all light wavelengths and intensity supplied by the sun. Normal fluorescent and compact fluorescent lights work well for low light plants. For higher light needs, special T5 fluorescents produce twice as much light as normal fluorescents. Use fluorescent lights that have the right wavelengths for plants. Plants need the blue wavelengths for photosynthesis and vegetative growth. Red wavelengths stimulate flowering and fruiting, states Simply Hydroponics.
Determine the light needs of your vegetable plants and which fluorescent lights will best meet their needs. Cool spectrum fluorescents provide the blue wavelengths needed for photosynthesis and green plant growth. Lettuce and similar leafy green plants do well under these lights.
Purchase enough fixtures of the right type for your lights. Adding more fixtures and reflectors will help keep the light intensity high.
Set up the growing area, providing a drip tray to catch spills below the plants. Hang the lights 6 to 15 inches above or beside the plants, using adjustable fixtures. Place the lights as close as possible to the plant without burning them. Place your hand under the light at plant level to make sure the plants are not getting too much heat.
Group plants of similar heights together.
Provide 14 to 16 hours of light daily. Use a timer if possible to keep the light schedule as normal as possible.
Adjust the lights as the vegetables grow. Raise the fixture to keep the light at least 6 inches above the plants.
Add an incandescent light or a warm spectrum fluorescent light to stimulate flowering. These lights provide the red wavelengths that are needed in small amounts during flowering and fruiting, according to the Texas Agricultural Extension Service. Decrease the light to 12 hours daily at this time.
Hand pollinate flowers of vegetables grown inside. Use a small paintbrush or cotton swab to gather and transfer pollen by brushing inside each flower. Brush flowers daily until the fruit begin to grow.
Watch for signs of burning. Plants too close to the light dry out and turn brown. Move the light farther away from the plants.
Watch for signs of too little light. Plants that don’t get enough light grow tall and leggy in an attempt to find more light. Leaves may be lighter in color and smaller. Add more fixtures and use reflectors or mirrors to reflect light back onto the plants.