When Do Walnuts Ripen? Understanding the Ripening Season of the Natural Brain Gold

Walnuts are rich in nutritional value and are known as the “natural brain gold.” The ripening period of walnuts varies depending on different varieties and climate differences, so when is the walnut ripening season?

1. The Ripening Period of Walnuts

The ripening period of walnuts varies depending on different varieties and climate differences. The ripening periods of some early-maturing varieties and late-maturing varieties can differ by 10 to 25 days. Under normal circumstances, the ripening period in northern regions is mostly from early to mid-September, while southern regions are relatively earlier.

2. The Harvest Season of Walnuts

When walnuts are harvested from August 25 to September 1, the walnut kernels are yellowish-brown or light brown. At this time, their flavor becomes fragrant, but they will be slightly astringent; if harvested after September 1, the walnut kernels appear white-yellow, have an oily fragrance and are crisp. Walnuts harvested later will be at a very high degree of maturity, the green husk will split open on its own, and at this time removing the green husk will be very easy, and the fruit surface after peeling will be clean and attractive.

Methods for treating the green husk include mechanical peeling, pile-retting peeling, and chemical peeling. After peeling, promptly wash off the residues with water, dry them, and then store them.

3. Pest and Disease Control Before and After Walnut Harvest

1. Diseases: mainly walnut black spot disease, walnut anthracnose, rot disease, and branch blight. The control methods are as follows.

① Promptly remove diseased fruits and diseased leaves and take them out of the orchard to avoid a large-scale outbreak.

② Before female flowers bloom, after blooming, and during the young fruit stage (May to June), spray once with 1:2:200 Bordeaux mixture or 50% thiophanate-methyl wettable powder at 500~800 times dilution, which can achieve a good disease-prevention effect.

2. Insect pests: mainly the walnut fruit moth (walnut black), longhorn beetles, carpenter moths, scarab beetles, slug moths, green-tailed moon moths, jewel beetles, etc. The control methods mainly include the following.

① Physical control: release poultry in the orchard, use black light lamps to trap and kill adults, manual capture, etc.

② Chemical control: before walnuts sprout, spray lime sulfur mixture to kill overwintering pests and diseases. The first spraying time is in the early egg-laying stage of the walnut fruit moth adults and before the larvae bore into the fruit, using 25% chlorbenzuron No. 3 at 1500 times dilution + beta-cypermethrin at 1000 times dilution for spraying, once every 10 days. During the active period of carpenter moth larvae, insert dichlorvos-soaked cotton into the insect holes to kill the larvae or prune off the infested branches and burn them. Dig open the soil around the root collar, inject 40% dimethoate emulsifiable concentrate at 20 times dilution into the insect holes, then seal them tightly with moist soil to kill the larvae.