One, Seedling Bed Construction
Tower mist culture involves constructing a tower frame on the seedling bed, with the bed serving as a collector for the nutrient solution and ensuring its uniform return. It is essential that the seedling bed is leak-proof and free of any compound leakage to prevent affecting the composition of the nutrient solution.
In the initial phase of construction, most seedling beds were typically made with brick-lined edges, which involved significant investment and affected future arable land reclamation, and this method is now rarely used. Currently, the technique of trenching and covering with film is employed for bed edges, offering speed, cost-effectiveness, and no damage to arable land. During construction, the span of seedling beds is usually between 80-120 centimeters, with a spacing of 60-80 centimeters between beds for management and operational pathways.
Two: Cultivation Rack Design
The selection of mist cultivation racks requires attention. The function of the racks is to both shape and support a three-dimensional farming space.
The components typically utilize 20-gauge hot-dip galvanized square tubes, which are milled at both ends. These can be assembled using screws for easy installation and future disassembly and transport. Hot-dip galvanized square tubes resist corrosion in nutrient solution environments, ensuring a long lifespan, and offer excellent load-bearing capabilities and strength, suitable for large or heavier plants. Installation should be carried out based on the actual design drawings.
Section 3: Selection of Planting Boards and Hole Drilling
Planting boards for mist cultivation predominantly use extruded foam boards, which serve to block light, maintain consistent plant spacing, and offer certain load-bearing capabilities. Previously, foam boards were used, but they had a short lifespan and were prone to shedding particles, aging when exposed to water. Extruded foam boards are thermal insulation materials that can mitigate temperature fluctuations in the root mist environment. Typically, boards with a density of 40-43 kg/m³ are chosen. The 2.5 cm thick extruded foam boards are used as planting boards, known for their long material lifespan, load-bearing capacity, and resistance to deformation.
Hole punching methods typically involve using an electric soldering iron to install sleeve inserts with the required diameter. The holes are created at a 45-degree angle on the board surface using a heat-melt technique. The inner walls of the holes are smooth, and nutrient fluid is less likely to leak out, reducing the growth of green algae and maintaining the cleanliness of the board surface.
The spacing between the holes in the planting board corresponds to the row spacing for cultivation, typically installed with a distance of 100*150 cm. The hole diameter for leafy vegetables is 2-3 cm, while for melons, it is usually 5 cm.
Section 4: Mist Cultivation Pipeline and Nozzle Installation
After installing the cultivation racks, arrange the misting pipes. Typically, 25mm diameter PVC pipes are chosen for misting tubes. For racks with a slope of 1.8 and a waist circumference of 1.5 on the ladder frame, install two misting pipes on each side of the waist. Place one pipe every 60 cm, with four pipes per rack. Each rack is equipped with a 60cm misting nozzle with a cross-head, ensuring the nozzles are aligned in a straight line for optimal spray effect.
Section 5: Construction of the Nutrient Solution Pond
The nutrient solution pond size differs from hydroponics; it does not store water in the Zhongzhi system, so it doesn't require as large a pond as hydroponics. Generally, a 1-1.5 mu area is designed with a 20-cubic-meter nutrient solution pond that serves a 1-1.5 mu area. Mist cultivation primarily utilizes the small buffer characteristic of gas mist, with a small pond and multiple configurations, which can reduce the difficulty of managing nutrient solution concentration and pH levels. Typically, underground ponds are used, with a depth of about 1.5 meters, a width of 2 meters, and the length can be determined based on actual needs. Ponds that are too long can be divided into multiple smaller ponds, with the pools interconnected.
