To be profitable, container production of horticultural crops requires precise control of water and fertilizers. Physical properties of horticultural substrates have been studied in order to help develop more effective irrigation and fertilization strategies. One of these physical properties–particle size–is incredibly important in substrates. The particle size distribution of a substrate influences its water holding capacity and pore size, which affect irrigation, drainage, and aeration. The pH, CEC, fertility, and stability (amount of decomposition and nitrogen immobilization by microbial populations) are also greatly influenced by particle size. Continue reading →