What to Do When Grape Fruit Set Rate Is Low? A Few Methods to Improve It
How can you improve the fruit set rate of grapes? What methods can make grapes bear more fruit? We also ask experienced readers to share their advice. The fruit set rate of grapes is the issue that readers who grow grapes care about most, so Zhongdi Web has compiled methods that can improve the fruit set rate of grapes. They are listed in detail below for readers' reference. Met...
How can you improve the fruit set rate of grapes? What methods can make grapes bear more fruit? We also ask experienced readers to share their advice.The fruit set rate of grapes is the issue that readers who grow grapes care about most, so Zhongdi Web has compiled methods that can improve the fruit set rate of grapes. They are listed in detail below for readers' reference.
Method 1: Ensure adequate nutrition for the grapevines:
Applying balanced or formulated fertilizer to grapevines is the main way to stabilize vine vigor and improve the fruit set rate. The base fertilizer for grapevines should be applied after harvest, with the application amount at about 60% of the whole year, usually mainly compost, barnyard manure, and organic fertilizer. If the vineyard soil is acidic soil, calcium magnesium phosphate fertilizer and plant ash can be applied.
Topdressing for grapes can be divided into 3 applications: the first is applied before and after grape budbreak together with irrigation, using nitrogen fertilizer, with the application amount at 15% of the annual total; the second is during the grape berry enlargement stage, mainly compound fertilizer, combined with human feces and urine or nitrogen, phosphorus, and potassium, with the application amount accounting for 30% of the whole year; the third is during the grape fruit coloring stage, mainly phosphorus and potassium fertilizer, with little quick-acting nitrogen fertilizer, accounting for about 10% of the annual fertilizer application amount.
In addition, borax or boric acid can be sprayed during the grape flowering stage to promote grape fruit set.
Method 2: Control excessive growth of new grape shoots:
If grapevine vigor is too strong or too weak, it is not conducive to flowering and fruiting. Only vigorous but moderate vine vigor can stabilize fruit set. If vine vigor is too strong, the vigorous growth of branches and vines will inevitably consume a large amount of nutrients, causing the new shoots that emerge the following spring to have poor flower formation and fruiting ability.
For varieties of the Kyoho group, strong pinching can be carried out before flowering, and after flowering the leaves of secondary shoots can be used to supplement organic nutrition. For tight-cluster varieties, in order to reduce their fruit set rate, the pinching time of the main shoot can be delayed so that the clusters become loose.
For grape varieties with strong secondary shoot development ability, fewer secondary shoots should be retained, and when necessary, "running a single cane plus renewal pruning" can be adopted, using winter bud secondary shoots to increase leaf area; while for varieties with weak secondary shoot development ability, appropriately more secondary shoot leaves should be retained.
Method 3: Reasonably retain fruit on grapevines:
If grapes are grown with a blind pursuit of yield without flower and fruit thinning, it will not only reduce grape quality, but also weaken vine vigor, leading to poor growth, poor quality of grape flower buds, insufficient maturity of grape branches, and few stored nutrients in the grape plant. It will also affect flowering and fruiting the next year and intensify grape flower and fruit drop.
Yield should be appropriately controlled. This can not only ensure normal fruiting, but also provide good vine vigor conducive to consecutive years of high yield. The normal grape yield per mu is about 1500-3000 kg.
Method 4: Prevent grape diseases and pests in time:
The key targets for grape control are black spot disease, downy mildew, white rot, and leafhoppers, etc. All of the above diseases and pests can cause grape flower and fruit drop. Also pay attention to weather forecasts and prevent damage from late frost. Click to view >>Control Methods for Grape Downy Mildew
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