Extreme low or high temperatures are not conducive to grape fertilization and fruit setting. Except for temperature control in facility cultivation, there are almost no options for open field cultivation. High temperatures can be alleviated by watering. Zinc deficiency in grapes can also cause grain size. After zinc deficiency, grape auxin synthesis is hindered and insufficient, resulting in poor, slow plant growth, less fruit setting, flower caps that are difficult to fall off, and large and small fruit grains. Lack of trace elements can also cause large and small particles, mainly calcium, boron, and zinc. Calcium and zinc during the budding stage, boron and calcium before flowering, and calcium supplementation during the expansion stage and after harvest. Of course, special attention should be paid to the input of phosphate fertilizer before flowering, and the timely supplement of nitrogen and potassium fertilizer after flowering.

Reasonably adjust the plant load: four-year-old grapevines weigh about 10 kilograms, 20 cm of amputation is required during flowering, tumors exceed 20 cm, and double ears are left with a special stand of more than 1 cm. Strong branches at corners and tips should be left with double spikes or double spikes with a single spike. Strictly control the fruit preservation time and operation. Fruits that do not meet the standards will be processed the next day. Label them well and do not process them too early. In addition, seed-free treatment can also prevent large and small particles, but it varies depending on the variety.

Boron deficiency in grapes causes difficulty in elongating pollen tubes, making it difficult for ovules to be fertilized and unable to form seeds. Boron deficiency causes large and small fruits. Generally, small fruits have no seeds or only one seed. The flower cap is not easy to fall off, and the fruit set is less on the grapevine. If the tree is too strong. Vegetative growth will compete with reproductive nutrition for nutrients. Resulting in the grapes becoming smaller and smaller due to lack of nutrients. However, if the tree is too weak, it will also affect the grape fruit setting, resulting in the production of large and small grapes.

During the pollination period of grapes, the relative humidity of the air should be maintained at about 55 to 60. Too much or too little water will produce large and small grains. If the pollination is uneven during the flowering period, it will easily lead to the occurrence of small and large grapes. In our case, we will water the grapes once before the flowering period, because the grapes cannot be watered during the flowering period. During the flowering period and the high temperature season, When the weather is dry, you can alleviate the high temperature through proper watering. At this time, if the phenomenon of large and small grains has formed, the first crop of fruits can be discarded and the second crop of fruits can be retained.