Variety selection and planting techniques of soilless and hydroponic vegetables!

by Krystal Zheng

Types and varieties of hydroponic vegetables

There are many types of vegetables suitable for hydroponic culture. At present, there are two common types, one is fruit vegetables and the other is leafy vegetables.

Fruits and Vegetables Hydroponic Vegetables

Due to the relatively long growth cycle of fruit and vegetable vegetables, generally about one year, and two to three nutrient solution renewal during the entire growth cycle from planting to harvesting, cultivation and management are more difficult, so it is not suitable Hydroponic cultivation.

At present, the main fruits and vegetables cultivated in our country are tomatoes, and the more common one is the hydroponic cultivation of tomato trees. Its characteristics are: strong disease resistance, long-season cultivation; hard fruit flesh, thick skin, not easy to crack the fruit; vigorous plant growth, strong fruiting ability; strong adaptability to environmental conditions, high temperature, low temperature, weak light, etc. All have certain resistance.

A tomato tree covers an area of  50-100 square meters, and the height of the plant is 2-2.5 meters. Therefore, tomato planting needs to be carried out in a relatively tall greenhouse. Since tomato is a herbaceous plant, the semi-vine stems cannot really support the lush branches and leaves like trees. The cultivation of tomato trees requires special supports to support the stems, leaves and fruits to form an ideal tree shape.

The cultivation of tomato trees requires the same temperature conditions as ordinary tomatoes. The temperature during the day is 25-28 degrees Celsius and the temperature at night is 15-18 degrees Celsius. If the temperature is higher than 30 degrees Celsius or lower than 12 degrees Celsius, tomato trees cannot grow normally. Therefore, the greenhouse for tomato tree cultivation should have heating facilities in winter and cooling facilities in summer to ensure that the growth of tomato trees provides a suitable temperature.

Light is an important environmental factor that affects the flowering and fruit setting of tomatoes, and weak light often causes flowers and fruits to fall. Therefore, it is advisable to choose a solar panel with better light permeability on the top of the greenhouse, and use shading nets to improve the light conditions.

The cultivation pond used for tomato tree cultivation, also called hydroponic bed, is a container for the growth of tomato tree roots. It usually uses a cement pond with a length of 3 meters, a width of 1.5 meters and a depth of 30 cm, and requires one plant per pond. The surface of the hydroponic bed needs to be covered with a white foam board to provide a dark growth environment for the root system and prevent the growth of moss.

There should be a water supply pipe above the hydroponic bed, and there should be a liquid return hole at the bottom of the bed to facilitate the circulation of the nutrient solution. In addition, there should be oxygenation devices, including air pumps and air tubes, whose function is to supplement oxygen to the nutrient solution in the hydroponic bed.

Leafy vegetables in hydroponics

Most leafy vegetables can be cultivated by hydroponics. The reason is:

First of all, leafy vegetables eat more stems and leaves of vegetables, and some are mainly eaten raw, which requires the products to be fresh, clean, and pollution-free. The hydroponic leafy vegetables are cleaner, with good taste and high quality.

Secondly, leafy vegetables are not easy to store, but in order to meet market demand, annual production is required. Hydroponic leafy vegetables can be planted, planted, harvested 365 days a year, and can be produced continuously without interruption, which is suitable for planned and contracted production.

Third, due to the short growth cycle of leafy vegetables, if there are no major physiological diseases in the middle, generally only one nutrient solution needs to be prepared from planting to harvesting, and no need to replace it midway.

Fourth, hydroponic leafy vegetables can avoid continuous cropping obstacles, have a high multiple cropping index, and produce high economic benefits.

There are many varieties of leafy vegetables suitable for hydroponic culture. The more common ones are: lettuce, spinach, cress, Chinese kale, Chinese cabbage, rape, Chinese cabbage, collard greens, and Begonia fimbristipula. Among them, lettuce is one of the most important and common hydroponic leaf vegetables.


Hydroponic vegetable facilities and equipment

The cultivation and planting of hydroponic vegetables are usually carried out in greenhouses. In order to ensure the normal and healthy growth of vegetables, the greenhouse must be equipped with light adjustment facilities, ventilation facilities, and temperature and humidity adjustment facilities. In the summer, a pest control board is also hung to prevent pests from occurring.

The composition of hydroponics facilities and equipment is composed of nutrient solution tank, seedling equipment, cultivation pond and cultivation board, liquid adding system, drainage system, circulation system, etc.

Nutrient solution tank

The nutrient solution tank is used to store the nutrient solution, and is generally placed underground in a tank made of bricks and cement. The specific width of the nutrient solution tank can be flexibly designed according to the greenhouse terrain.

Nursery equipment

The seedling raising equipment is used for sowing and raising seedlings, and consists of a seedling tray and a breeding substrate. Seedling trays are mostly made of flat-bottomed watertight plastic, with a length of 60 cm, a width of 30 cm, and a height of 3 cm. Breeding substrates can be selected from sponge blocks with larger porosity or degradable rock wool blocks.

Cultivation pond and cultivation board

The cultivation pond is the main site for vegetable growth and the main part of the hydroponic facility. Vegetables are planted on cultivation plates and placed in cultivation ponds. The roots of vegetables get water, nutrients and oxygen from the nutrient solution in the pond to meet the physiological needs of normal growth.

Cultivation ponds are generally made of cement, and their shapes and sizes vary according to the types of vegetables. The cultivation ponds for cultivating leafy vegetables are generally larger, up to hundreds of meters in length and tens of meters in width, and the specific size varies. It depends on the area of the greenhouse. The cultivation ponds for growing fruits and vegetables are generally small, no more than 3 meters long and 1.5 meters wide. Both types of cultivation ponds are rectangular, and the pond depth is required to be 30 cm. In addition, there are trench-type and pipe-type cultivation ponds, but these two types of cultivation ponds are mostly used for small-scale production and ornamental purposes.

Cultivation board, also called planting board, is a device used to fix vegetable roots, prevent dust intrusion, block light from entering, prevent algae production and keep the temperature of the nutrient solution in the cultivation pond stable. Cultivation boards are generally made of polystyrene boards. According to the types of vegetables and the needs of different growth periods, their specifications and sizes are also different. Generally, the length is 80 to 100 cm, the width is 50 to 70 cm, and the thickness is 3 cm. Arrange the planting holes with a diameter of 3 cm, which are divided into 288-well plate, 99-well plate, 72-well plate, 24-well plate, 18-well plate, 6-well plate, etc. according to the hole distance.

Add liquid, drain liquid system and nutrient liquid circulation system

The feed liquid of hydroponics facilities is generally pumped by a water pump to pump the nutrient solution into the cultivation pond. The water level is maintained at a depth of 5 to 8 cm in the pond, and the facility for adding liquid to the cultivation pond consists of an iron or plastic liquid addition main pipe and a plastic liquid addition branch pipe.

The nutrient solution is drawn from the nutrient solution tank by the water pump, enters the cultivation tank through the main and branch pipes, and is absorbed by the roots of the vegetables. The nutrient solution higher than the drain port flows back to the nutrient solution tank through the drain groove along the drain port, thereby completing a cycle.

hydroponic vegetable nutrient solution

Preparation and management of hydroponic vegetable nutrient solution

The nutrient solution used in hydroponic vegetables is an aqueous solution that dissolves fertilizers in water and absorbs them through the roots of vegetables to supply water and nutrients necessary for the growth and development of vegetables. The preparation and management of nutrient solution is a key technology in hydroponics technology, which plays a decisive role in the growth of vegetables.

The main fertilizers used to prepare the nutrient solution are: calcium nitrate, potassium nitrate, nitric acid, magnesium sulfate, potassium silicate, potassium dioxophosphate. Micro-fertilizers include: chelated iron, sodium borate, manganese sulfate, copper sulfate, zinc sulfate, and ammonium molybdate. The specific dosage and the concentration ratio of the nutrient solution vary depending on the type and variety of vegetables, the geographical situation of the cultivation area, and the season. In the process of cultivation and management, it is necessary to observe and adjust in time according to the actual growth of vegetables.

The nutrient solution not only supplies the water and nutrients necessary for the growth of vegetables, but also supplies the dissolved oxygen needed for the respiration of vegetable roots. Therefore, aeration facilities must be installed in the cultivation pond to increase the amount of dissolved oxygen in the nutrient solution in time, which is extremely important for the cultivation of hydroponic vegetables.

The renewal and supplement of nutrient solution is the main task of nutrient solution management in the process of hydroponic vegetable cultivation. Generally, during the entire growth period of fruit and vegetable vegetables from planting to harvesting, the nutrient solution needs to be updated two to three times; while for leafy vegetables during the entire growth period from planting to harvesting, if there is no large area of ​​physiology Diseases, the nutrient solution does not need to be renewed, just replenish the amount of nutrient solution consumed once or twice a week.

Fourth, the technological process of hydroponic vegetables

Sowing seedlings

Planting is generally carried out in the morning. Before planting, prepare the planter and select the seeds. When sowing, turn on the power of the seeder, then pour the seeds into the sucker of the seeder, turn on the switch, shake evenly, so that the seeds are absorbed in the holes of the sucker. Then pour out the excess seeds.

Make sure that each hole has seeds and maintain the quality of each seed. Buckle the breeding substrate upside down on the sucker of the seeder, with the hole side down. Then close the bottom cover, turn the planter over, turn off the switch, open the bottom cover and set it aside. Check that there are seeds in the holes of each breeding substrate. Move the breeding substrate to the seedling tray. Place the seedling tray on the seedling platform, and use a watering can to pour the nutrient solution so that the nutrient solution is immersed in the breeding substrate.

Moisturizing the seeds after sowing is very important. Spray the nutrient solution with a watering can once or twice a day to keep the surface of the seeds moist and provide the necessary nutrients for the seeds to germinate and emerge. Where conditions permit, the tidal platform can be used to raise seedlings, and the breeding substrate can be immersed in the nutrient solution twice a day, and the time for each immersion is 40-60 minutes.

During the breeding period, attention should be paid to the temperature control, the light should not be too strong, and the sunshade net can be used to adjust the light when necessary. Regularly observe and understand the germination and growth of seeds. Under normal circumstances, the seedlings can germinate within 3-5 days, and the seedlings will emerge within 5-7 days.


Planting seedlings

Before planting, prepare a planting plate. Depending on the species, a 288-hole or 99-hole planting plate can be used.

Planting is also called a thinning seedling, which is to transplant the substrate seedlings with good growth conditions on the planting plate and put them in the cultivation pond for cultivation. Planting is usually carried out 3-7 days after sowing. When planting, the breeding substrate is broken one by one, and the seedlings are inserted into the planting holes on the planting plate. When planting, keep your hands light and don't hurt the seedlings. The planting board should be filled with seedlings, and the planting board should be placed in the cultivation pond as soon as possible after it is full.

The management of lettuce after planting is very simple. In addition to ensuring the normal circulation of the nutrient solution and controlling the temperature, it does not require cultivating, weeding, spraying, etc. Usually pay attention to observe the growth of the seedlings.

In order to facilitate the normal growth of lettuce, so that it has enough space for growth and development, it is necessary to divide the lettuce as necessary. Generally, the first seedling division is carried out 7-11 days after sowing. The first division of seedlings is also called two-thinning seedlings. Seedlings that are about to be planted on a 288-hole or 99-hole planting plate are transferred to a 72-hole or 24-hole planting plate for continued cultivation.

When dividing the seedlings, pull out the seedlings gently, and then gently insert them into the planting holes on the cultivation plate. When inserting, use a hook to gently hook the root system of the seedling so that the root system fully contacts the nutrient solution. After transplanting, put the cultivation plate into the cultivation tank as soon as possible.

Seedling division will be carried out on the 14th to 21st days after sowing. Secondary seedling division, also called three-thinning seedling, is the last seedling division, which means that the seedlings planted on 72-hole or 24-hole cultivation plates will be transferred to 18-hole or 6-hole cultivation plates. Generally, 6-holes will be planted on each cultivation plate. 9 lettuce.

Daily management

The daily management of hydroponic lettuce is very simple, mainly to control the temperature and humidity, adjust the light and regularly ventilate.

Lettuce likes to be cold and grows best in the temperature range of 10-25 degrees Celsius in winter and spring. It grows slowly below 10 degrees Celsius, and grows poorly above 30 degrees Celsius, and it is easy to bolt and bloom. Generally, the temperature should be controlled at 15-21 degrees Celsius during the day and 10-15 degrees Celsius at night.

The adjustment of light is mainly to use shading nets, and the ventilation generally uses exhaust fans.

From the 20th to 40th day after sowing, the pond should be moved, that is, the lettuce grown in the cultivation pond is moved to the preformed pond. When moving the pond, take the cultivation plate out of the cultivation pond and put it into the transportation tank, and the nutrient solution must be injected into the tank in advance. Then take it out from the transport tank and put it into the preformed pool. At this time, the growth of lettuce should be observed.

30-50 days after sowing, there will be a transfer of the lettuce, that is, the lettuce that grows in the pre-formed pond will be transferred to the vegetable pond. The second one can be harvested about 10 days after moving the pond.


Harvest packaging

The growth cycle of hydroponic lettuce is generally 40 to 60 days, and it can be harvested at this time. Harvesting can be carried out according to actual needs. Lettuce sown on the same day may not necessarily be harvested on the same day, and can be left in the growing pool for continued planting. Choose well-growing, large and leafy vegetables for harvest.

When harvesting, first take the cultivation plate out of the vegetable growing tank and put it into the transportation tank, then take it out from the transportation tank and put it on the harvesting table. In the harvesting process, the rotten leaves and yellow leaves around the root system should be removed, and the root system should be removed at the same time. However, sometimes in order to visualize the characteristics of hydroponic vegetables, it is better to bring a part of the clean root system. The root system can be coiled up when harvesting.

The harvested lettuce should be packaged in time to ensure its fresh quality. If it cannot be put on the market in time, in order to prevent the aging of the lettuce tissue after harvesting and maintain its freshness, it can be stored in an environment of 0-5 degrees Celsius. The general storage period is 5-7 days.

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