The sun is an excellent form of light and is very affordable, but it may not always be available. Growing vegetables with artificial lights provides growers with an opportunity to defeat the seasons and to grow food in a variety of locations. Production goals and crop choice matched with the right light can enable growers to produce food using artificial lighting.
Cost of artificial lighting fixtures and continued operation must be considered when determining production costs and goals. This is not well described in alternative home vegetable production systems.
There is an impressive amount of new research about artificial lighting in futuristic agricultural production facilities, but these systems may not be suitable for the curious indoor cultivator. In commercial horticultural production facilities, investments in artificial lights are justified by increased revenues. However, for small scale home production systems, you can make working with artificial lights as simple or space station as you desire, but please consider the cost of the light fixture and the electricity needed for continued operation of the light. This overview is a distillation of research based information about growing ornamental plants indoors and space age research about controlled environment agriculture, in addition to personal experience growing vegetables with artificial lights.
Very Basic Overview of Artificial Grow Lights
- T12 6500K- micro greens and germination
- T5 High Output Grow Light- lettuce and leafy greens
- High Intensity Discharge- HID
- Metal halide
- vegetative growth- more blue wavelengths
- High pressure sodium
- flowering and fruiting- more red wavelengths
- Pros/ Cons: Lights are powerful enough for flowering and fruiting crops, but they are a bit pricey, run hot and need cooling, and therefore require a lot electricity
- Metal halide
- Light Emitting Diodes- LED
- Energy efficient- more light energy per watt
- Potential to be wavelength specific, meaning more of the energy from the light is used by the plant
- Optimal photosynthesis occurs in the blue wavelengths 425- 450 nanometers, and the red wavelengths 600- 700 nanometers
- Light percentages and other wavelengths of light are being researched now and into the future
- Intensity of the lights and percentages of red, blue, white, and sometimes other colors will depend on the crop you are trying to grow. While the right LEDs can produce enough light in the right wavelengths for flowering and fruiting crops like tomatoes, the technicalities involved still make this very challenging and expensive.
- Not all LEDs are equal – Do your research! Technology is improving at light speed.
Notes for your consideration
- Short term, low profile crops like lettuces, leafy greens, and some herbs can be grown very successfully using artificial light systems that are not that complicated. Long term, flowering and fruiting crops like tomatoes, peppers, and strawberries require a symphony of light and temperature signaling the growth processes.
- Light coverage will play a role in where and how the light is positioned above your crop and how the light penetrates through your crop. Some lights may hang 1 foot above your crop, while others may need to be 4 feet away to provide the optimal range of light and temperature.
- Grower must provide the light that the plant needs without exceeding optimal temperature ranges for plant growth.
- Fans can help moderate temperature while maintaining good plant transpiration.
- Lights need to be mounted or hung somewhere, and they could be distracting.
- Consider harvesting and maintenance of plants when selecting location.
- Put your lights on a timer.
A couple words of caution for your consideration:
- Lights can be breakable.
- Electricity and water is a very dangerous combination.
Excited to learn more?
Introductory – Kansas State Research and Extension: Lighting options for starting seeds (LEDs vs. Fluorescent)
Intermediate to Advanced – Purdue University, Measuring Daily Light Integral in a Greenhouse
Advanced – Michigan State University, Light Management in Greenhouses and Controlled Environments (links to quality science based resources)
Advanced – University of Arizona Controlled Environment Agriculture Center, Lighting and Radiation
Advanced – The Economics of Lighting Young Indoor Plants