Most of the new and excellent woody seedlings produced by facility nurseries are used for cultivating finished seedlings, except for selling them as hole tray seedlings. Traditional nurseries often rely on ground planting and seedling starting (with a certain size of soil ball) to cultivate commercial seedlings and project seedlings. In contrast, facility nurseries are mostly containerized. Container cultivation allows seedlings to be transplanted at any time throughout the year, especially during high-temperature and dry seasons, without significantly affecting survival rates. This ensures a quick seasonal landscape effect for garden plants, a short production cycle, good quality, easy transportation, high transplanting survival rates, and simplified management. However, container cultivation also involves challenges such as substrate formulations, cultivation management, and investments in supporting technologies and equipment. Therefore, the container cultivation of facility nurseries should adhere to a moderate scale and steady development principles.
Choosing Cultivation Containers
Containers are the foundation of soil-less cultivation for seedlings. Currently, facility nurseries in China utilize two main categories of containers. One type includes soft plastic containers, such as planting bags or square plant pots. The other includes hard containers made of materials like hard plastic, rubber-plastic composites, iron, or wood. These hard containers can be further categorized into detachable, barrel-shaped, and fixed designs. Detachable and barrel containers allow repositioning of seedlings as they grow, while fixed containers are generally used for larger seedlings over 15 cm and are immovable.
When selecting containers, factors such as seedling type, size requirements, and growth duration should be considered to match the right tree with the right pot, thus minimizing production costs. For instance, annual container seedlings for sale are commonly cultivated in plastic pots for planting with dimensions of 12 × 10 cm. For two-year-old shrub-type seedlings, the first year often involves using plastic pots, while the second year transitions to larger options, such as planting bags measuring 21 × 18 cm or 16 × 26 cm. This practice not only maximizes the number of seedlings per unit area but also significantly reduces production costs since plastic soft bowls are only a fraction of the cost of rigid containers.
For larger shrubs or trees, a combination of soft and rigid containers is often employed. For example, shrubs with a crown diameter exceeding 80 cm may initially be grown in cost-effective soft plastic containers for the first two years and then transferred to rigid containers like rubber-plastic or hard plastic pots for further cultivation. For large trees with a chest diameter of 15-20 cm, fixed root-control containers measuring 80 cm in diameter and 70 cm in height are commonly used. Meanwhile, detachable containers, although expensive, are reserved for cultivating high-grade, grafted varieties such as purple-leaved Canada Bauhinia. These plants may spend their initial years in draining pots, which facilitate excellent drainage for plants in pots, before being transferred to detachable containers for further growth.
Cultivation Substrate
The choice of substrate is critical for successful container cultivation, as it directly impacts the growth of seedlings. The substrate should be rich in organic matter, well-aerated, lightweight, and free from pests and weed seeds. It should also have suitable pH levels for the plants being grown. To balance cost and performance, substrates often include a mix of rotting huller, peat, and dry pond mud. Rotting huller provides excellent drainage and air permeability, making it ideal for use in square plant pots or similar containers. However, its poor water and fertilizer retention necessitates supplementation with peat and pond mud to improve these properties.
Adding slow-release granular fertilizer to the substrate ensures steady nutrient availability throughout the growth period. This type of fertilizer has a low salt index, making it suitable for different types of substrates and plants while preventing substrate compaction. Proper substrate preparation also involves adjusting the pH levels to meet the specific requirements of coniferous (pH 4.5-5.5) or broad-leaved (pH 6-8) seedlings. Once mixed, the substrate should be disinfected to eliminate potential pathogens, ensuring a healthy growing environment for the seedlings.
Potting Fields and Irrigation Systems
Newly potted container-grown seedlings require protective facilities and efficient irrigation systems to thrive. For instance, nurseries often use greenhouses equipped with sunshades to diffuse sunlight and prevent heat damage to seedlings. Irrigation systems, such as percolation irrigation, are also essential. In this setup, water enters a nursery pool through floor drains, and the substrate within containers absorbs the water through capillary action, maintaining an optimal balance of moisture.
For shrubs grown in plastic pots for planting, irrigation is typically carried out using swing-arm sprinklers. Meanwhile, drip irrigation systems with needle-and-arrow drip heads are more suitable for larger containerized trees. Efficient irrigation methods are vital for sustaining plant health and ensuring uniform growth, particularly in larger setups where hundreds of thousands of container seedlings may be cultivated annually.
Container Cultivation and Drainage Management
Effective drainage is a cornerstone of container cultivation. Containers like draining pots are designed with adequate drainage holes to prevent waterlogging, which can lead to root rot and other issues. Ensuring proper drainage for plants in pots also helps maintain the substrate’s aeration, allowing roots to access sufficient oxygen. For large-scale nurseries, employing containers with integrated drainage features is especially important to reduce labor and maintenance costs.
Additionally, the type of container used plays a significant role in optimizing drainage. For example, soft plastic containers are often preferred during the initial growth stages, as they are lightweight and cost-effective. However, as the plants mature, they are transferred to hard plastic or rubber-plastic containers that offer superior durability and drainage capabilities.
Industrialized Seedling Production
Container cultivation represents an industrialized approach to seedling production, requiring mechanized fertilizer management, pruning, handling, and packaging processes. By adopting intensive cultivation management practices, nurseries can improve efficiency and reduce costs. Containers like square plant pots and plastic pots for planting are integral to this system, as they are versatile, cost-effective, and suitable for a wide range of plant species.
The integration of modern irrigation systems, advanced substrates, and optimized container designs ensures that container cultivation remains a sustainable and profitable method for producing commercial seedlings. By focusing on key factors such as drainage, substrate quality, and container selection, nurseries can achieve higher survival rates, better plant health, and reduced operational costs.
Post time: Nov-18-2024