Temperature and humidity management of grape germination
August 01 09:16:58, 2025
In the initial phase of grape cultivation, temperature management plays a crucial role. The sprouting of grapevines is triggered by rising temperatures, and the effective accumulated temperature must be at least 450°C to 500°C. In unheated solar greenhouses, the warming process begins in mid-January, and after approximately 30 days of gradual warming, the grapes start to sprout. It's important not to cover the vines with curtains, as this can disrupt the natural temperature rise and germination cycle.
During the temperature rise and germination period, it is essential to avoid rapid temperature increases. If the temperature rises too quickly or becomes too high, the branches may sprout prematurely while the ground temperature has not yet risen sufficiently. This can lead to an imbalance between the growth of the upper and lower parts of the plant, resulting in uneven sprouting and poorly developed fruit clusters. To prevent this, the temperature should be carefully controlled. In the first week, the daytime temperature should be maintained between 15°C and 20°C, with nighttime temperatures around 6°C to 10°C. By the second week, the daytime temperature can be increased to 15°C to 20°C, and the night temperature should be raised to 10°C to 15°C. In the third week, the daytime temperature can go up to 20°C to 25°C, with nighttime temperatures kept at 13°C to 15°C until full germination occurs.
Next, humidity management is equally important during the germination phase. This is the period when grapevines require the most water. Insufficient moisture can lead to delayed germination, reduced germination rates, or even failure to germinate. Once germination begins, it is necessary to water the plants thoroughly several times, with each irrigation providing about 30 mm of water. This should be repeated 2 to 3 times, and the greenhouse vents should remain closed to maintain a relative humidity of over 90%. As the temperature rises during the day, the humidity may drop, so using tools like a sprayer to mist the grapevines can help create a more favorable environment for germination.