Carbon dioxide is essential to the process of photosynthesis. Most plants grown indoors require a minimum co2 concentration to enable them to photosynthesise efficiently and produce energy in the form of carbohydrates. These concentrations of co2 are enough for plants to grow and develop normally. Lower concentrations can seriously impede plant growth and general plant health. In fact, a drop of 25% in natural co2 concentrations can easily inhibit growth by over 50%