Six tricks for coloring Fuji apples to make the fruit color more evenly

The fruit of Red Fuji begins to color earlier than that of Guoguang (Ralls Janet), but the process is slow. It generally begins to color from mid to late August, and after early to mid September its coloring is still not as fast as that of Guoguang. To improve the coloring degree of Red Fuji, in addition to a series of work such as rational pruning and shaping and timely pest and disease control, the following measures can be implemented starting in early September:

1. Control nitrogen. After September, no more nitrogen fertilizer should be applied as a top dressing; a scientific water supply method of frequent and shallow irrigation should be adopted to maintain relatively stable soil and air temperatures.

2. Leaf removal. Remove the 1 to 2 old leaves shading the apples above, so as to increase the utilization rate of direct light on the fruit surface.

3. Spraying. Spraying 500 ppm of rare earth on the tree canopy increases the rate of fully red fruit by 12%, increases anthocyanin by 1 to 3 times, increases the weight of 100 fruits by 6%, and raises the yield by 15%. In addition, spraying vigorous trees with ethephon below 1000 ppm or 5000 ppm of monopotassium phosphate also has an obvious color-enhancing effect.

4. Laying film. Laying plastic film between the rows and plants of the trees can increase the intensity of reflected light, significantly increase the coloring of the fruit top and the calyx depression, and raise the sugar content by 1 to 2 degrees.

5. Protecting roots. During the coloring period of Red Fuji apples, the practice of frequently hoeing the tree disk and damaging the shallow root system should be avoided, as this is beneficial to the synthesis of cytokinins and helps increase the sugar content of the fruit.

6. Late harvest. The timing of harvest has a relatively large impact on apple coloring and quality. If harvested too early, the apples color poorly and are of poor quality. Apples generally have a suitable harvest period 175 to 180 days after petal fall. The closer to the later stage, the greater the temperature difference between day and night, and the more favorable it is to fruit coloring. Therefore, it is better to harvest Red Fuji later.