The cultivated soil must be well drained, and it is better to use the soil with more organic matter content. Pot culture soil can be made up of humus or peat soil plus 1 /3 of river sand or perlite plus a small amount of base fertilizer.
When planting, it should be buried a little deeper, so that the new buds can absorb fertilizer. In May June, when growing vigorously, fertilizer and water should be applied once every 1-2 weeks. The late effect compound fertilizer is better than the late autumn one. In addition to adding organic fertilizer to the potted plants, it is necessary to manage the fertilizer and water properly in the ordinary maintenance process.
The principle of "dry and wet" shall be followed in watering. During the growth period, timely watering shall be carried out to keep the basin soil moist. When the growth is vigorous in summer, watering shall be carried out twice a day. After late autumn and rainy days, watering shall be controlled. The relative air temperature of growing environment is required to be in the range of 70-80% & nbsp; the low relative air humidity will make the leaf tip dry.
It is necessary to keep high air humidity around plants. In summer, water should be sprayed on the leaves and the ground to increase the air humidity. Keep the leaves clean in winter. Spray water or scrub the leaves frequently.
The suitable growth temperature of sunflower is 25-35 ℃. Cold tolerance is weak, very sensitive to low temperature, overwintering temperature should be above 10 ℃, if it is lower than 5 ℃, the plant will suffer. The main reason for the death of sunflower in winter and spring is the low temperature. In summer, 50% of the sun should be covered, and direct sunlight should be avoided. Even if the sun is exposed for a short time, the leaves will be scorched yellow, which is difficult to recover. In the room to be placed in a bright place, too dark on the growth of sunflower. In winter, it can be placed in a place with good light.
(1) trimming. In winter pruning, when the plants enter the dormancy or semi dormancy period in winter, the branches such as thin, weak, disease and insect, dead and too dense should be cut off.
(2) change basin. The pots were changed every 2-3 years in early spring, and the old plants could be changed every 3-4 years. After the basin is changed, it should be placed in the place with half shade and high air humidity, and the withered and yellow branches and leaves should be cut off in time.
(3) nitrogen deficiency. The color of leaves changed from uniform green to yellow, and the growth rate of plants slowed down. The control method is to increase the application of nitrogen fertilizer, and spray 0.4% urea on the root or leaf for 2-3 times according to the situation.
(4) potassium deficiency. The old leaves faded from green to bronze or orange, and even the leaves curled, but the petioles still kept normal growth. With the increase of potassium deficiency, the whole crown faded, and the plant growth was blocked or even died. The control method is to apply potassium sulfate in soil. According to the dosage of 1.5-3.6kg/plant, the potassium sulfate is applied four times in a year, in addition, 0.5-1.8kg magnesium sulfate is added, so as to achieve balanced fertilization and prevent the occurrence of magnesium deficiency.
(5) pest control. When spring comes, there may be whitefly damage due to poor ventilation. It can be sprayed with 200 times spray of GAD's enemy worm and leaves and roots should be sprayed. If good ventilation can be maintained regularly, the wasabi will not be prone to whitefly. If the environment is dry and poorly ventilated, there will also be red spider damage. It can be treated with 3000-5000 times diluent spray of speed mite ketone 20% wetting powder.
