The materials for making plug trays are generally polystyrene foam, polystyrene, polyvinyl chloride and polypropylene. Manufacturing methods include compression molding and blistering, as well as injection molding. Due to the early technology and demand, injection molding is the mainstay. However, due to the high cost of thick cavity disks caused by injection molding technology, it is only used for scientific research and a few people. Over time, seedling trays have proven to greatly improve the survival rate of seedlings. Slowly developed thinner and thinner plastic trays produced by blistering and compression molding technology, because the products are relatively light and cost-effective, and are used on a large scale by the people.

 

The shapes of the holes in the seedling trays are mainly square and round. The square holes generally contain about 30% more matrix than the round holes, the water distribution is relatively uniform, and the seedling root system is more fully developed. But it is not to say that all vegetable and fruit seedlings are suitable for square holes, and round holes have its advantages and special characteristics. The size of the standard plug tray is 540mm × 280mm. Due to the different hole diameters, the number of holes is between 15-512. For cultivation of small and medium seedlings, 50-288 hole trays are most appropriate.

 

The color of the nursery trays affects the temperature of the plant roots. White polystyrene foam disks have better light reflectivity, and they are mostly used for early seedling raising in summer and autumn to help reflect light and reduce heat accumulation in the roots of seedlings. Compared with plastic plugs, foam plugs are more expensive and can cause foam sticking to the hand when used. So now more and more people choose transparent materials, which can not only achieve the advantages of foam, but also can be reused. In winter and spring, black seedling trays are selected, because of their good light absorption, which is beneficial to the young seedling root system. After the seedlings grow up, they should start using the root-control rapid seedling technology, move it into the root-control rapid seedling container, and continue to grow.

 

Advantages of using plug seedlings:

(1) Save seed consumption and reduce production costs.

(2) The emergence is neat and maintains the consistency of plant seedling growth.

(3) Can be used with various manual and automatic seeders to facilitate centralized management and improve work efficiency.

(4) The root system is not damaged during transplanting, the seedlings are slow and the survival rate is high.