Cell trays, also known as hole trays, specific operational methods:

1. Hole Disc Selection and Disinfection: The hole disc dimensions are typically 54.9×27.8cm, with 72-hole and 108-hole sizes being most suitable. Place the seedling trays in a solution of diluted bleach powder (prepared by mixing 1 kilogram of bleach powder with 99 kilograms of water), soak for 8-10 hours, then remove and let dry for later use.

2. Substrate Preparation: The commonly used substrate materials for plug seedling propagation include peat moss, vermiculite, and perlite, with a ratio of peat moss: vermiculite: perlite at 2:1:1 being widely adopted. It is also necessary to add appropriate amounts of inorganic and organic fertilizers to the substrate, typically 2.6 to 3.1 kg of 15:15:15 NPK compound fertilizer and 10 to 15 kg of defatted chicken manure as organic fertilizer per cubic meter. The substrate pH should be between 5.8 and 7.0. Peat moss, derived from semi-decomposed marsh vegetation, has a pH of 3.8 to 4.5, is fine-textured, and has poor aeration, often mixed with vermiculite or perlite. Substrate sterilization is required.

3. Potting: First, prepare the growing medium and place it in the trays. Be careful not to compact it too tightly, as doing so can damage the physical properties of the medium, reducing its air and water-holding capacity. The correct method is to use a scraper to move the medium from one side of the tray to the other, ensuring each cell is filled evenly, especially the corners and edges. The medium should not be overfilled, allowing each compartment to be clearly visible after filling.

4. Hole Pressing: After the trays are assembled, they should be pressed to facilitate seed insertion. This can be done using a custom-made hole presser, or by stacking the trays vertically, with 4 to 5 trays per layer, placing an empty tray on top. Then, place both hands flat on the trays and press uniformly until the desired depth is reached.

5. Sowing: Place one seed per hole in the pre-furrowed tray, avoiding any missed seeds. For seeds with a low germination rate, plant two seeds per hole.

6. Seedling Coverage: After sowing, cover the seed trays with vermiculite. The method involves pouring vermiculite onto the trays, using a scraper to spread it from one side to the other, removing any excess, and ensuring the vermiculite is not too thick, level with the compartments is ideal.

7. Seedling Tray Placement: Place the seeded trays on the seedling bed and thoroughly water them with clean water, ensuring gentle and even watering to prevent washing out the substrate and seeds from the holes. Then, cover the bed with a layer of ground film to prevent moisture loss from the trays. While covering, place some small bamboo sticks on the trays to create a gap between the film and the trays to avoid sticking. Alternatively, you can soak the trays in a water tray before sowing, allowing water to slowly seep up from the bottom of the trays for more even absorption, and then place them in the seedling bed.

8. Seedling Management. Seedling Replacement: After seedlings emerge, remove the mulching film covering the seedbed promptly to prevent the formation of "tall seedlings." Once the seed leaves unfurl, immediately thin and replace seedlings, removing excess seedlings from single holes and transplanting them into empty spots, while also deleting any extra seedlings within the holes. After replacing the missing seedlings, immediately spray the seedbed with clean water. Water Management: The growing medium in cell trays has a small volume and high porosity, absorbing less water. The seedbed's water supply buffering for seedlings is low, so any negligence can lead to water loss. During the hot summer and autumn seasons, water should be sprayed promptly in the cool morning and evening hours.