When is the best time to harvest walnuts?
When is the best time to harvest walnuts? Please explain. Walnut yield depends mainly on the size of the walnut nuts and the weight of a single nut. When walnuts approach maturity, the size of the fruit is basically set. In walnuts harvested at different times, there is no obvious difference in the average values of longitudinal diameter, transverse diameter and ridge diameter. However, in walnuts harvested early, the...
When is the best time to harvest walnuts? Please explain.
Walnut yield depends mainly on the size of the walnut nuts and the weight of a single nut. When walnuts approach maturity, the size of the fruit is basically set. In walnuts harvested at different times, there is no obvious difference in the average values of longitudinal diameter, transverse diameter and ridge diameter. However, in walnuts harvested early, the accumulation of internal dry matter is still increasing. Survey data show that at this time the average weight of a single walnut on the tree increases by 0.07 grams per day, and within a certain period, the later the harvest, the greater the weight gain. For every 10 days the harvest is postponed before fruit drop, the yield can increase by 10%. Before harvest, the weight of a single fruit increased rapidly before August 25, and the increase in yield occurred mainly before August 25. From this it can be seen that harvesting walnuts early will inevitably reduce the yield.
The closer walnuts are to maturity, the fuller the fruit, the greater the weight of the kernel, and the higher the kernel yield gradually becomes. The increase in the weight of a single walnut is mainly the increase in the weight of the walnut kernel. In walnuts harvested at a properly delayed time, the weight of the walnut kernel increases markedly, by an average of 18% per day. Tests show that the kernel weight increases sharply as the harvest time is postponed, and the increase is greater than the increases in kernel yield, fullness and so on.
Before August 25, for every week the harvest is delayed, the walnut kernel weight increases by more than 13%. Tests by the Beijing Forestry Research Institute show that when walnuts are harvested half a month early, the kernel yield and oil yield drop by 5-10%. When the harvest time is postponed from August 28 to September 19, the oil content of the walnut kernel can increase by 80%. When harvested before August 25 in Shangluo, Shaanxi, the kernels are thin and small and often have empty or half-filled nuts, failing to meet commercial requirements.
How early or late walnuts are harvested affects walnut quality. In early-harvested ones, the walnut kernel is brown or dark brown, with a bland taste and extreme astringency. When harvested from August 25 to September 1, the walnut kernel is yellow-brown or light brown, with a taste that becomes fragrant and slightly astringent; when harvested after September 1, the walnut kernel is white-yellow, with an oily fragrance and a crisp texture. Walnuts harvested late have a high degree of maturity, the green husk splits open naturally, removing the green husk is easy, and after peeling the surface is clean and attractive, making them easy to sell.
In most walnut-producing areas, the local people generally harvest walnuts on the early side, because they fear losing walnuts, or fear that a late walnut harvest will affect wheat planting, or want to sell walnuts early on the market at a high price. They have the habit of beating walnuts at "Chushu" (End of Heat), which is 10-15 days earlier than the suitable walnut harvest time. At present, many places still beat walnuts at "Chushu". Rushing walnuts onto the market early to sell at a high price may bring in a bit more money, but the total walnut output is greatly reduced, product quality declines, the selling price falls, and overall returns are greatly affected. In fact, the loss outweighs the gain.
Walnut trees planted sparsely have less consistent maturity times, while walnut trees planted in solid blocks have more consistent maturity times. In river valleys, river courses, hills and middle- and low-altitude mountain areas, harvesting in early September is best; in high mountain areas, early to mid-September is best. Walnuts mature around the "Bailu" (White Dew) solar term, and it is advisable to postpone the harvest by a few days; harvesting in stages and batches is best.
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