And any other methods below:

4. The application of phosphorus and potassium fertilizer

Mineral nutrition also has a significant impact on fruit coloration. Too much nitrogen is unfavorable to the development of red. The direct cause is that nitrogen and available sugars synthesize organic nitrogen, thereby reducing the need for synthetic anthocyanins for sugar; the indirect reason is to promote the growth of branches and leaves, affecting tree illumination. Therefore, it is not advisable to apply more nitrogen fertilizer after entering August. In particular, it is forbidden to apply nitrogen fertilizer before harvesting, and pay attention to increasing the application of phosphorus and potassium fertilizer. Phosphorus and potassium fertilizer can accumulate sugar and transport it to the fruit. The coloration of the fruit is closely related to the sugar content. When the sugar content reaches 12 degrees or more, the fruit begins to color. The higher the sugar content, the better the coloration.

5. Moderate drought

Fruit coloring and moderate drought during bagging are beneficial to fruit coloration. But be careful not to lack water. Therefore, water should be poured and water should be poured as little as possible according to the weather conditions, otherwise the fruit coloration and sugar content will be affected.

6. Pick up the bag at the right time

Picking a bag too early or too late is not conducive to fruit coloring. The red Fuji apple picking bag in the northwest fruit area is suitable for late September. If there is rain, picking up the bag after rain is good; the low-altitude fruit area in the east should be finished by October 5 at the latest. The double-layer paper bag is first taken out of the outer bag, and the inner bag is removed after 3 to 4 sunny days. The single-layer paper bag first tears the outer bag from the bottom, and then completely picks up the bag after 3 to 5 sunny days. The bag picking time depends on the variety. Generally, the mid-late ripe red variety should be 15 to 20 days before harvesting, and the late-maturing red variety should be removed from the bag 20 to 25 days before harvest. In order to avoid the stimulation of the fruit after the bag is picked, the medicine should be sprayed before picking up the bag.

In summary, comprehensively adopting the above ction management measures will effectively solve the coloring problem of some apple varieties, achieve the beautiful appearance of redness at the time of harvest, improve quality and increase profits.

Zhengzhou Delong Chemical CO., Ltd. is the production base of plant growth regulators in China, which established in 2009, specializing in offering plant protection products. If you have any question, contact us any time.