Different groups of plants respond in physically different ways to various wavelengths of radiation.
Light plays an extremely important role in the production of plant material.
No gardener can achieve good results without adequate light. If you intend to grow indoors, avail yourself of some of the reading material that has been published on this subject. If you are having trouble growing good plants, then light is the first factor to question. A number of lighting options exist for hydroponic gardeners. Once you have answered those two questions, you will have significantly narrowed your options.