What Kind of Lighting Is Needed to Grow Tomatoes?

Outdoor Lighting

• Tomatoes require bright, direct light for six to eight hours every day. They will grow vegetation in partial shade, but cannot bloom or produce fruit under those conditions. Plant tomatoes in outdoor sites with full sun exposure, quick drainage, good air circulation and open space. Outdoor tomatoes do best at 24 to 36 inches in the row, with 4 feet between rows, to allow each plant full sun exposure.

Outdoor Soil and Watering

• Tomatoes cannot grow on sun and air alone. Amend outdoor soil to provide a rich, crumbly foundation for tomato nutrition. Turn over the top 10 inches of soil and break it up, then add 3 to 4 inches of organic compost. The University of Missouri Extension recommends starting outdoor tomatoes with 8-32-16 or 6-24-24 granular fertilizer to encourage rooting. Water outdoor tomatoes with 1 to 2 inches of water every week.

Indoor Lighting

• Grow indoor tomatoes in natural or artificial light. Place the plants in windowsills to get daytime sunshine, and supplement with halogen or fluorescent lighting. Keep the lights on long enough to give tomatoes eight hours of exposure every day.

Indoor Potting, Soil and Watering

• The Colorado State University Extension recommends 6-inch pots for indoor tomatoes. Give each plant 5 gallons of space for growing, and plant multiple tomato plants depending on the size of your pots. Use plastic pots with drainage holes, to keep the plants from sitting in water. The Ohio State University Extension recommends mixing your own indoor planting soil of potting soil, perlite, sphagnum peat moss and compost, in equal parts, with balanced, slow-release fertilizer. Indoor tomatoes dry more quickly than garden tomatoes, and require 2 inches of water every three to four days.