Introduction of spinach hydroponic culture technology in summer

Spinach is one of the most important vegetables in northern China in spring. Spinach likes cold and can not tolerate heat. The suitable temperature for growth is 15 ℃-20 ℃. It is difficult to cultivate spinach in summer because of high temperature and heavy rain. In recent years, some Shouguang vegetable farmers have successfully cultivated spinach in summer by adopting hydroponic culture technique in greenhouse. The main points of cultivation techniques are introduced as follows: 1. Variety selection. Summer cultivation of spinach must choose heat-resistant varieties, such as Japanese pioneer, Xinkang heat-resistant No. 3 and so on. 2. Sowing and raising seedlings. When sowing in May, the planting cup is generally used to concentrate on raising seedlings in the seedling shed. Put ceramsite at the bottom of the cup at a height of 2 cm-3 cm from the edge of the cup, cover it with fine sand after sowing and drench with water. The seedling shed is covered with the sunshade net, and the sunshade net is removed in time after emergence to prevent the seedlings from overgrowing. 2-3 true leaves set seedlings, leaving 1 strong seedling in each cup. 3. Cover the sunshade net. Strong sunshine and high temperature in summer seriously affect the growth of spinach. Silver-gray shading net should be covered on the roof of the greenhouse to reduce light and temperature. The shading net can reduce the light intensity by about 30% and the temperature by 2 ℃-3 ℃. 4. Planting. When the seedlings are 5 cm-6 cm high and have 3-4 true leaves (seedling age 18 days-20 days), they can be planted in the cultivation trough with 60 plants per square meter. 5. Nutrient solution management. ① nutrient solution formula. 1kg water plus ammonium sulfate 379mg, potassium dihydrogen phosphate 306mg, potassium sulfate 150mg, calcium nitrate 186mg, magnesium sulfate 120mg, manganese sulfate 1.54mg, zinc sulfate 0.22mg, copper sulfate 0.08mg, ammonium molybdate 0.02mg, Fe--EDTA22 mg. ② nutrient solution concentration management. The nutrient solution concentration and EC value of spinach growth should be adjusted appropriately with the growth process. At the initial stage of planting, the plant is small and requires less nutrients, the concentration of nutrient solution can be reduced appropriately, the EC value is suitable in 0.8ms/cm--1.3ms/cm, and in the middle and later stage of growth, EC value is controlled at 1.3ms/cm--2.0ms/cm. Check every 7 days or so, record water consumption and EC value changes, and timely supplement and adjustment, each supplement is about 20% of the initial amount. 30%. ③ water level management. At the initial stage of planting, the plant is small, the root system is underdeveloped, and the water level of the nutrient solution should be high, which should be about 1 cm away from the foam planting plate. With the progress of growth, the water level can be gradually reduced, 2 cm-3 cm from the planting plate is appropriate, so that part of the roots are exposed to the air, which is conducive to the growth and development of roots and plants. ④ pH regulation. The suitable pH value for spinach growth is 5.8 murmur6.3. In the process of cultivation, with the growth of plants, the pH value of nutrient solution shows a downward trend, which should be detected by acidity meter regularly. When the pH value is less than 5.8, 0.5% Murray 1.0% NaOH solution can be used to adjust. ⑤ nutrient solution circulation. The nutrient solution should be recycled every day to ensure a balanced supply of nutrients and increase the content of oxygen in the solution to make spinach grow neatly and consistently. Generally circulate twice a day, once in the morning and once in the afternoon, and each time the liquid is supplied for 1 hour-2 hours. 6. Harvest. Hydroponic spinach rarely occurs diseases and insect pests. It has a lot of water content, tender stems and leaves, fast growth rate and high yield. It can be harvested 30-45 days after planting and when the plant height is 25-35 cm.