Hydroponics is a new type of soilless plant cultivation.

At its core, the roots of plants are directly infiltrated in a nutrient solution that replaces the soil and provides plants with water, nutrients, oxygen, and other growth factors so that they can grow properly.

In the soil, organic matter is transformed by the decomposition of soil microorganisms and animals into the mineral nutrients needed for plant growth. The water in the soil dissolves these mineral nutrients (usually in ionic form), making them available for absorption by the plant's roots.

In order for plants to obtain balanced nutrition, the various substances in the soil must be in optimal proportions; unfortunately, such soils are rare in nature.

After adopting hydroponics, plants can absorb nutrients and water directly from the nutrient solution through their roots, and one can manually mix a nutritionally balanced solution to achieve a balanced plant diet. This is obviously much easier than finding soil.

Because these solutions are contained in containers, they can be recycled and will not flow into the soil and have an impact on the environment, which is safe, reliable, and sustainable.

The common hydroponic techniques are as follows.

1. Deep Flow Technique (DFT): mostly used in early-built plant factories and greenhouses and other facilities for agricultural cultivation.

The advantages of DFE are as follows:

a. Hanging cultivation. The plant is suspended from the planting plate, part of the root system is inserted into the nutrient solution, and part of the root system is aerated in the space between the nutrient solution surface and the planting plate, which has the nature of half hydroponics and half aeroponics, and it is easier to solve the water and air contradiction of the root system.

b. Liquid layer is deep. The root system extends into the deeper liquid layer, and the single plant occupies more liquid volume. Because the liquid volume is more and deeper, the concentration of nutrient solution (including total salt and nutrients), dissolved oxygen, pH, temperature and water are not easy to change drastically, which provides a more stable growth environment for the root system. This is the outstanding advantage of deep liquid hydroponics.

c. Suitable for the cultivation of a wide range of crops. In addition to root and tuber crops, almost all fruits and vegetables and leafy vegetables can be cultivated.

2. Nutrient Film Technique (NFT): mostly applied to the completed new plant factories, the world's largest plant factory built by CSCS in 2016 utilizes a new modular cultivation device to realize three-dimensional planting of NFT.

NET advantages:

a. Low investment in facilities, easy and convenient construction. the planting tanks of NFT are made of lightweight plastic or spliced with corrugated tiles, the structure of facilities is light and simple, easy to install, easy to dismantle, and low investment cost.

b. Intermittent liquid supply, shallow and flowing liquid layer. The nutrient liquid layer is shallow, the crop roots are partly immersed in the shallow nutrient liquid and partly exposed to the moisture in the planting tank, and the nutrient liquid in the shallow layer is circulating and flowing, which can better solve the root respiration demand for oxygen.

c. It is easy to realize the automatic management of the production process.

3. Aeroponics is a soilless cultivation technology that uses filtered and treated nutrient solution under pressure to atomize the nutrient solution into fine droplets through an atomizing spray device and spray them directly to the plant root system to provide the water and nutrients needed for plant growth.

The advantages of fog cultivation are as follows.:

a. The problem of oxygen supply to the root system can be solved well, and there is almost no phenomenon of poor growth due to lack of oxygen to the root system.

b. High utilization of nutrients and water, fast and effective supply of nutrients.

c. Easy to realize three-dimensional, can make full use of the space in the greenhouse, and increase the number of planting and yield per unit area. The utilization of greenhouse space is 2 to 3 times higher than that of traditional flat cultivation.

d. Easy to realize the automation of cultivation management

Each technology has its own advantages and disadvantages, and all have a relatively large number of practical production applications. There are some variants of each method, but most of them are the same.