Systems and associated apparatus and methods are described for growing plants in a dense and efficient manner in an indoor environment using artificial light. The systems are configured to hold a high density of plants at a relatively close, substantially fixed distance from a light fixture that provides artificial light for growth of the plants. As the plants grow, the plants are transferred to one or more following stations or stages, each of which is configured to hold the now larger plants at the same relatively close, substantially fixed distance from a light fixture. By providing multiple stages to accommodate plant growth, and maintaining the close positioning of the plants to the light fixtures, the impact of the artificial light on the growth of the plants is maximized and the efficiency of the electrical energy use is increased.