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How to Grow Vegetables in Artificial Light

By Cindy Hill ; Updated September 21, 2017

Many garden vegetables require six to eight hours of full sun each day to thrive, flower and set fruit. Reproducing the effect of this amount of sunlight with artificial light sufficient to grow tomatoes, peppers or eggplants is nearly impossible--and prohibitively expensive. Leafy green vegetables like lettuce, spinach, microgreens and mesclun mixes grow in less than full sun, as do smaller, swiftly-grown root crops like radishes and baby beets or turnips. These lower-light vegetable crops can all be grown under artificial lights under the right conditions.

Place one warm and one cool florescent tube in each florescent lighting fixture. Hang the fixtures from adjustable chains over waterproofed shelving in a location that will remain at a temperature of at least 65 degrees F throughout the day and night.

Plug all of the florescent lights into a multi-plug electrical outlet extension, and plug the extension into a light timer.

Mix 4 parts potting medium with 1 part well-aged compost. Water well with rainwater until it is a crumbly texture. Add 1 tbsp. powdered kelp to each gallon of potting mixture.

Fill seed trays and 1-gallon nursery pots lightly with potting mixture. Do not compact soil. Let the soil settle in the containers over night, then top off the containers with additional soil mix.

Plant root crop vegetable seeds in 1-gallon containers, to the depth recommended on the seed packets but at only two-thirds the recommended horizontal spacing. Plant leafy vegetable seeds in seed trays at the depth and spacing recommended for each variety on its seed packet.

Place the containers on the shelves, putting all the seed trays on one shelf and all the 1-gallon containers on another. Place clear plastic seed tray covers over the trays and clear plastic deli or take-out food container covers over the 1-gallon pots.

Adjust the florescent light fixtures so they are as close as possible to the container covers without touching them. Use shims to raise the containers if you can not get the lights close enough. Turn the lights on and leave them on 24 hours a day until the seeds germinate.

Carefully slide the trays and containers out from under the lights every third day to water them. Use rainwater to avoid salt build-up in the soil.

Set the light timer to keep the lights on 16 hours per day once the plant shoots emerge.

Remove the covers when the vegetable plants reach the top of the clear plastic covers. Water as necessary to preclude the plants from completely drying out. Raise the lights as the plants grow, keeping the florescent tubes as close to the tops of the plants as possible.

Transplant leafy green vegetables to individual 4-inch pots when they are about 3 inches tall. Fertilize all your indoor vegetable seedlings with fish emulsion or compost tea once a week.

Harvest all vegetables grown under artificial lights at the baby stage--when root vegetables are about 1 inch to 2 inches in diameter and leaf vegetable plants are about 6 inches high.

 

Things You Will Need

  • Florescent lighting fixtures
  • Cool and warm florescent light tubes
  • Sturdy, waterproofed shelves
  • Adjustable light-hanging chains
  • Multi-plug electrical outlet extension
  • Light timer
  • Potting medium
  • Compost
  • Rain water
  • Powdered kelp
  • Seed-starting trays with internal mesh drainage tray
  • 1-gallon nursery pots or large decorative planters
  • Seeds for leafy green vegetables and small root vegetables
  • Clear plastic seed tray covers
  • Clear plastic domes from deli and take-out food containers
  • Shims
  • 4-inch pots
  • Liquid fish emulsion fertilizer or compost tea

Tips

  • Use contact paper or non-toxic pond sealer to coat your indoor vegetable growing shelves. Shelves that have not been waterproofed are likely to collapse at some point in the growing season.
  • Select vegetable varieties with very short growing seasons noted on the seed packets. Short-season and fast-growing miniature varieties do best indoors.

About the Author

 

A freelance writer since 1978 and attorney since 1981, Cindy Hill has won awards for articles on organic agriculture and wild foods, and has published widely in the areas of law, public policy, local foods and gardening. She holds a B.A. in political science from State University of New York and a Master of Environmental Law and a J.D. from Vermont Law School.