Selection of substrate:
A good substrate should have the following characteristics: ideal moisture capacity; Good drainage capacity and air capacity; Easy to re wet; Good porosity and uniform void distribution; Stable vascular bundle structure, less dust; Appropriate pH value, 5.5-6.5; It contains appropriate nutrients, which can ensure the nutrient demand before cotyledon expansion; Very low salt level, EC less than 0.7 (1:2 dilution method); The size of matrix particles is uniform; No plant diseases, pests and weeds; The quality of each batch of matrix shall be consistent.
The role of vermiculite with smaller particles is to increase the water retention of the matrix rather than porosity. To increase the drainage and permeability of peat matrix, perlite instead of vermiculite should be added. On the contrary, if you want to increase the water holding capacity, you can add a certain amount of small particle vermiculite.
Pay attention to the following points: Although imported peat is ideal as the source of raw materials for seedling substrate, due to its high price and non renewable resources, western countries gradually use processed coco坚果壳粉为底物的来源,the effect is the same. They call it coconut peat.
1. The matrix shall be fully wetted before filling, generally 60%. Hold a handful of matrix with your hand, and there is no water extrusion. If you loosen your hand, it will form a mass, but if you touch it gently, the matrix will disperse. If it is too dry, the substrate will collapse after watering in the future, resulting in poor air permeability and poor root development.
2. The filling degree of each hole should be uniform, otherwise the hole with less base quality will dry faster, resulting in uneven water management;
3. The cavity matrix of large seeds such as melons should not be too full;
4. Avoid squeezing the substrate, otherwise it will affect the air permeability and drying speed of the substrate, and the seeds will rebound due to the too tight pressure of the substrate, resulting in different depths when the seeds finally germinate.