How to manage lettuce hydroponic culture

Lettuce (var. Ramosa Hort.) Leaf lettuce, also known as goose lettuce, shipping mark lettuce, lettuce, belongs to the genus Asteraceae lettuce. For annual or biennial herbaceous crops, leaves long Obovate, dense into cabbage-like leaf balls, edible, crisp, tender and refreshing, slightly sweet. Lettuce is native to the Euro-Mediterranean coast and is domesticated from wild species. The ancient Greeks and Romans ate it first. Lettuce has been introduced into China for a long time, and there is a lot of cultivation along the southeast coast, especially in the suburbs of big cities and Guangdong and Guangzhou areas. in recent years, the cultivated area has expanded rapidly, and lettuce has also entered the table of ordinary people from hotels and restaurants.

The main categories of lettuce

According to the growth morphology of leaves, lettuce can be divided into heading lettuce, wrinkled lettuce and upright lettuce.

Heading lettuce

The main characteristic of heading lettuce is that its terminal leaves form leaf balls. The leaf blade is entire, serrated or parted, the leaf surface is smooth or wrinkled, and the terminal leaf forms a globule, round or rounded. The main varieties are Dahu 659, avant-garde 75, Salinas, Beishan No. 3, Mamick, Green and so on.

Wrinkled lettuce

The main characteristic of wrinkled lettuce is that it does not bear balls. Basal leaves, leaf blade long oval, petiole longer, leaf margin wavy notched or deeply parted, leaf surface wrinkled, clustered leaves like large flowers. The main varieties are "Hongfan" purple leaf lettuce, safflower leaf lettuce, green wave, Dongshan lettuce and so on.

Upright lettuce

The main characteristics of upright lettuce are long and narrow leaves, upright growth, entire or serrated leaves, thick leaves, thick meat and poor flavor. The variety of this variety is few, the distribution area is not wide, and it is seldom planted in China.

How to manage lettuce hydroponic culture?

Compared with general soil cultivation, hydroponic lettuce has the advantages of good quality, high commercial value, less diseases and insect pests, no continuous cropping obstacles and so on. We carried out an experimental cultivation of lettuce in water culture in February last year. Among them, the method of static hydroponic culture of lettuce is simple, easy to operate, and suitable for popularization and use in production. The following is a brief introduction to its cultivation and management techniques.

1. Variety selection and seasonal arrangement: lettuce likes cold and cool, grows best in the temperature range of 15 ℃ ~ 25 ℃ in winter and spring, grows slowly below 15 ℃, grows poorly above 30 ℃, and is easy to bolt and blossom. Hydroponic lettuce is suitable for loose leaf lettuce.

two。 Preparation of nutrient solution and selection of cultivation containers: the formula of nutrient solution is to add 600 grams of calcium nitrate, 600 grams of potassium nitrate, 350 grams of magnesium sulfate and 150 grams of ammonium dihydrogen phosphate per ton of water. In production, cultivation trough or cultivation pond can be used; in family cultivation, pots, bowls, boxes, etc., can be used to ensure that there is no leakage.

3. Seedling planting:

1) Seedling: take the seedling plate and use vermiculite as the seedling substrate, soak the vermiculite with water before sowing, spread the seeds evenly on the vermiculite, then cover a layer of vermiculite equal to twice the seed, pour through the water, and the seedlings can emerge in 5-7 days at the temperature of 20 ℃. After emergence, the seedlings were irrigated with nutrient solution with EC value (the main index of water quality standard electrical conductivity) of 1.6-1.8.

2) planting: take the foam board, punch a hole every 20 cm, the aperture is 2.5 cm, and cover the mouth of the water culture container tightly. The nutrient solution was placed in the container with an EC value of 1.6 to 1.8. When the lettuce seedlings grew to 2 true leaves, the seedlings were divided and planted. First of all, wash the vermiculite from the root of the seedling, wrap the sponge strip in the stem base, and then stuff the seedling into the foam plate hole. Keeping the stem base dry and ventilated can greatly reduce the occurrence of rhizome base diseases.

4. Management and harvest: the management process of hydroponic lettuce is very simple. After planting, in order to keep the nutrient liquid level stable and consistent, the nutrient solution can be added once every 2-3 days, the water temperature is 20 ℃-22 ℃ and the pH value is 6-6.5. When the seedling has 3 or 4 true leaves, the EC value is 1.8 / 2, and the nutrient solution is added according to the situation, which can grow into a commercial dish in about 20 ~ 25 days.

When cultivated at home, you can use the way of picking leaves, eat with picking, and keep fresh. Production is generally an one-time harvest. In order to directly show the characteristics of hydroponic vegetables, it is better to take part of the white root system. In order to reduce the content of nitrate in lettuce, there is no need to supplement nutrients, only water is added a week before harvest.

5. Diseases and insect pests: there are few diseases and insect pests in hydroponic lettuce. In the hydroponic culture of nutrient solution, it is important to keep the nutrient solution clean, because once a root disease occurs, it will spread quickly, resulting in irreparable losses. In addition to disinfecting the nutrient solution, the nutrient solution should be thoroughly updated once a month. Aphids, red spiders and other insect pests sometimes occur in summer, which can be controlled by avermectin with high efficiency and low toxicity.