Lighting For Beginners, Part 2: Let There Be Light
With current technology, there is simply no light source that can equal the sun. This has to be the working assumption of any gardener who ventures into the world of artificial lighting.
Believe it or not, sunlight does have its limitations. About half the energy of sunlight comes in the form of infrared radiation. In many gardening applications, this intense heat generated by the sun is an advantage, but there are situations in which it could be a limitation.
In addition, sunlight is a truly broad-spectrum light source. Like the heat, in most applications this is an advantage, but if your goal is to manipulate the spectral quality of light, in order to induce flowering out of season for example, sunlight again could be a limitation.
Both of these limitations apply to unique situations only and are amenable to corrective measures, such as shading and venting excess heat. But there is one obvious limitation over which you, as a grower, have no control--availability.
