The importance of using seedling trays

The seedling tray is the place where seedlings grow and develop, while the substrate is the main source of nutrition for seedlings, and the hole tray is the main source. The basic requirements for seedling substrate include perlite, peat (peat), vermiculite, etc. The commonly used mixed substrates of peat and vermiculite for seedling cultivation internationally are locally sourced materials in some regions of China. Light substrates are mixed with some garden soil, and an appropriate amount of compound fertilizer is added to form the seedling cultivation substrate. However, the substrate for mechanized and automated seedling cultivation cannot be supplemented with soil.

The overall requirement of the hole tray seedling substrate is to ensure that the seedlings are supplied with water, oxygen, temperature, and nutrients as much as possible. The main physical and chemical properties affecting the seedling substrate include: pH value of the substrate, cation exchange capacity and buffering performance of the substrate, total porosity of the substrate, etc. The degree of decomposition of organic matrix is directly related to the bulk density, total porosity, adsorption and buffering properties of the matrix. The higher the degree of decomposition, the greater the bulk density, and the smaller the total porosity. Generally, a medium degree of decomposition matrix is preferred.

The pH value of different substrates varies, with peat having a pH value of 4.0 to 6.6, vermiculite having a pH value of 7.7, and perlite having a pH value of around 7.0. Most vegetable and flower seedlings require a pH value of slightly acidic to neutral. Cation exchange capacity is the total amount of exchangeable cations adsorbed by organic and inorganic colloids of a substance. The cation exchange capacity of high-level peat is 1400~1600mol/kg, shallow peat is 700~800mmol/kg, humus is 1500~5000mmol/kg, vermiculite is 1000~1500mmol/kg, perlite is 15mmol/kg, and sand is 10~50mmol/kg.