A greenhouse is a "tool" that can be used to facilitate the growing of plants. Generally, the tool is fitted for the job, and not the other way around. Growers need to determine what plants will be produced before making a decision about the type of greenhouse needed to accomplish the job. Depending on the crops to be grown, a conventional greenhouse may not even be needed. Instead, a simpler structure could more economically extend the growing season into spring and fall. For example, if the primary target is an early start date for farmers markets, row covers or a high tunnel may be quite adequate to handle the job.