Seedling Raising Methods and Key Technical Points for Growing Watermelons in Winter

Watermelons are generally a fruit only available in summer, but with the development of growing techniques, growing watermelons in winter is no longer a difficult problem. So that everyone can eat watermelons all year round, more and more watermelons are grown in greenhouses, so how do you raise seedlings for growing watermelons in winter?

1. Improve the insulation and heating measures of the seedling shed. Replace polyethylene film with Xin Gao Zhi Mo, and the insulation and performance are greatly improved, which can raise the shed temperature by 1°C~2°C. Temporary heating equipment such as a fire wall or heating stove should be installed in the shed. Carry out artificial heating when necessary.

2. Subject watermelon and rootstock seeds to low-temperature treatment. Soak the seeds in Xin Gao Zhi Mo to enhance the cold resistance of the seedlings. Place the soaked seeds that are about to be sprouted in a freezing environment of around 0°C for 24 hours, then place them under suitable temperature conditions to sprout. When the seeds show white, treat them at -1°C for 12~18 hours each day. Then switch to 18°C for 12~6 hours, for a total treatment of 3~5 days, and then place them under suitable temperature conditions to sprout.

3. Strengthen management after grafting. The first week after grafting is the wound healing stage, and the shed temperature should be kept at 20°C~30°C. When it is below 18°C at night, artificial spraying of Xin Gao Zhi Mo should be carried out to raise the temperature. The grafted seedling bed should be strictly sealed for 3~6 days to maintain the relative temperature inside the bed. For the first 3 days, it must be completely shaded, with only weak scattered light allowed through. On the 4th day, gradually expose to light. After 6 days, gradually ventilate. After the 7th day, remove the shading material and increase the amount of ventilation. Make the grafted seedlings adapt to the normal seedbed environment.

1. Strengthen management during severe weather. Management during periods of continuous overcast, rain and snow, and strong cold waves is an important part of whether seedling raising succeeds or fails. Pay attention to listening to weather forecasts and take insulation and heating measures before the cold wave arrives. During rain and snow, a second layer of film must be placed over the straw mat. During continuous overcast days, increase light as much as possible on the premise that no freezing damage occurs. If the bed temperature drops after uncovering the straw mat, then the straw mat should be uncovered and covered again before 3 p.m. If the bed temperature drops only slightly, it can be uncovered and covered as you go. Do not leave it uncovered for several days. When there is rain or snow, uncover and cover the straw mat as you go during breaks in the rain and snow. If light is insufficient for a long time, fluorescent lamps can be used for artificial supplementary lighting. After a long period of overcast followed by sudden clearing, uncovering the straw mat should be done slowly, otherwise it is easy to cause seedling flash or even seedling collapse. If seedlings are found to be wilting, cover them with shade immediately, and wait until the watermelon seedlings return to normal before uncovering again. Repeat this several times until they no longer wilt. Then uncover all the straw mats, and after that enter normal management.

5. Watermelon seedlings grow slowly during the seedling stage, so manage early to promote early development. After the vines spread, control fertilizer and water to prevent excessive vegetative growth and create conditions for fruit setting. Choose better node positions for artificial supplementary pollination.

① Water management:

Watermelons should be watered at least 2~3 times throughout the growing period. After the vines spread, the leaves increase and the sunshine duration is long, so the water requirement increases, and a round of “vine-pulling water” must be applied. When the young fruit grows to the size of a fist, water well for fruit swelling to ensure watermelon yield, quality, and normal growth and development. After that, whether to water can be decided according to the climate at the time and soil moisture conditions. Stop watering one week before harvest.

② Fertilization management:

Watermelon is a fertilizer-loving crop, and rational fertilization is one of the important measures to ensure high-quality and high-yield watermelons. The general principle is: apply seedling-promoting fertilizer cautiously, apply vine-spreading fertilizer skillfully, and apply fruit-swelling fertilizer heavily.