Growing plants on Mars can reduce the amount of re-supply that a long term human presence will require. A plant growth structure has been designed to test plant performance in a derived Martian atmosphere. The unit will support different lighting and nutrient systems to allow for a large range of plant experiments. The plant growth structure will be tested in a Martian simulator, which is currently under construction at the Kennedy Space Center. The simulator is a commercially available Thermotron environmental testing chamber (1.22m x 1.22m x 1.52m). The Thermotron can accommodate the input of a derived. Martian atmosphere whose composition will be defined by the experimenter. Carbon dioxide, oxygen, nitrogen, and argon will be the major constituents. Testing will be done to determine the temperature, humidity, and pressure ranges that the unit can control. The unit should be able to maintain a pressure of between 133 Pa (1 Torr) and 101.3 kPa (760 Torr) and a temperature between 16°C and 30°C. For plant growth, the relative humidity will be maintained between 55% and 85%. Tests with plants will be done to verify that the structure can handle the increased water load generated by the vegetative plant growth. Plant tests will begin upon successful performance verification of the plant growth structure.