How to manage greenhouse grapes in winter? A full breakdown of the key technical points

Pruning

① Pruning timing. For greenhouse-cultivated grapes, winter pruning should be carried out after the vines have dropped their leaves and have fully entered deep dormancy. It generally begins in mid-December and is completed before the end of December; doing it too late will affect subsequent management work.

② Pruning method. The specific pruning method is determined by the different trellis systems used, the characteristics of the variety, and the vigor of the vine.

???? Clearing the orchard and disinfection

① Clearing the orchard. After grape pruning is finished, remove all dead branches and fallen leaves in the orchard and peel off the old bark on the trunk and main canes, then burn them in a centralized pile and bury them deeply to reduce sources of disease.

② Disinfection. Use 2~3 degrees Baumé lime sulfur plus 0.5% sodium pentachlorophenate to spray and disinfect the orchard floor, trellis, and plants thoroughly once. In early February, at the bud swelling stage, spray again with 0.5~1 degree lime sulfur plus 0.2% sodium pentachlorophenate to eradicate sources of disease.

? Calcium cyanamide treatment

After winter pruning of greenhouse grapes, treating the grape buds and canes with 15%~20% calcium cyanamide solution can promote early sprouting by 3~5 days and increase the sprouting rate by about 30%. Treatment time: from the end of December to early January of the following year. It is best to carry it out at noon on a sunny day (between 10 a.m. and 3 p.m.).

? Covering the greenhouse

The timing of covering the greenhouse should be appropriately arranged according to the characteristics of different cultivated varieties. Varieties with a short chilling requirement, such as Jinxing Wuhe, Zaoyu, and Ziyu (chilling requirement 700~1000 hours), can be covered in early January. Varieties with a long chilling requirement, such as Fujiminori, Summer Black, and Jingya (chilling requirement 1100~1300 hours), can be covered in mid-to-late January, and this must be completed by the end of January at the latest.

Fertilizer and water management

After the greenhouse is covered, irrigate thoroughly once in time and keep the whole greenhouse closed. One week before sprouting (from the end of January to early February), apply 15 kg of urea per mu or 30 kg of ammonium bicarbonate plus 3 kg of boron fertilizer, then irrigate once more. At the same time, spray the grape buds and canes once with 0.5% urea solution plus 100 mg/L gibberellin to promote sprouting and increase the sprouting rate.

? Temperature and humidity management

① From after covering the greenhouse to before sprouting. Keep the whole greenhouse closed and relatively maintain a high-temperature, high-humidity state inside, with the maximum temperature controlled below 35°C. If the critical temperature is exceeded, ventilate appropriately to cool down; when humidity is below 90%, spray water on the grape canes to increase relative humidity.

② From after sprouting to the bud swelling stage. Keep the maximum temperature below 30°C and the minimum temperature above 5°C. If it falls below the minimum critical temperature, take insulation measures (such as double-film covering), and keep relative humidity below 60%. If humidity is too high, cover the protected rows in the orchard with plastic film, which both lowers humidity and raises ground temperature, regulating the balance between aboveground and belowground growth. Xiadelong