PET Seedling trays，also known as hole tray，has become an important tool in the factory seedling production process.Whether it is flowers or vegetables，hole tray seedling cultivation is the most fundamental transformation in modern horticulture.The materials used to manufacture the socket are generally polystyrene foam，polystyrene，PVC，polypropylene，etc.Manufacturing methods include blow molding and injection molding.General vegetable and ornamental plant seedling trays are made of polystyrene material.

The shape of the hole in the seedling tray is mainly square and circular，and the matrix contained in the square hole is generally about 30%more than that in the circular hole.The water distribution is also relatively uniform，and the seedling root system is fully developed.The size of the standard hole plate is 540mm×280mm，due to different pore diameters，the number of pores ranges from 18 to 800.For cultivating medium and small seedlings，it is advisable to use 72-288 hole trays.

The color of the seedling tray can affect the temperature of the plant roots.The white polyphenyl foam plate has good reflectivity，and is mostly used for early seedling raising in summer and autumn to reflect light and reduce heat accumulation in seedling roots.In winter and spring，black PET plants are chosen as PET Seedling trays because of their good light absorption，which is beneficial for the root system of small seedlings to turn green.After the seedlings grow up，they should start using root control seedling cultivation techniques，move them into root control seedling containers，and continue to grow.

The materials used to manufacture the socket are generally polystyrene foam，polystyrene，PVC，polypropylene，etc.Manufacturing methods include blow molding and injection molding.General vegetable and ornamental plant seedling trays are made of polystyrene material.

Advantages of using hole seedlings:

(1)Save seed usage and reduce production costs.

(2)The emergence of seedlings is neat，maintaining the consistency of plant seedling growth.

(3)It can be used in conjunction with various manual and automatic seeders，facilitating centralized management and improving work efficiency.

(4)When transplanting，it does not damage the root system，slows down the seedlings quickly，and has a high survival rate.