Key Techniques for Heat Preservation and Humidity Enhancement in Overwintering Tomato Cultivation

Now is exactly the time for cultivating overwintering tomatoes. Because the growing returns of this crop of tomatoes are relatively high, they are widely planted in northern provinces of China such as Henan, Hebei, and Shandong. In overwintering tomato cultivation, heat preservation and humidity enhancement are essential growing techniques, so exactly how should heat preservation and humidity enhancement be done?

1. Increase the light transmittance of the greenhouse film

Use highly light-transmitting film and promptly clean dust, snow, and other debris off the greenhouse film. This can increase light and raise the greenhouse temperature.

2. Improve the heat preservation of straw curtains

The straw curtains covering the greenhouse should be thick and sturdy. To improve heat preservation performance, in deep winter, to prevent rain and snow from wetting the straw curtains, an additional layer of ordinary agricultural film or old film from previous years can be placed over the straw curtains.

3. Increase the heat preservation of the back wall

When building the back wall, a layer of bricks can be attached to the earth wall, or a hollow heat-preservation wall can be built, with straw or polystyrene foam boards filled inside the wall, which also works very well. In severely cold areas, a heated wall can be built directly to help raise the temperature.

4. Dig cold-proof trenches outside the greenhouse

Dig cold-proof trenches 40-60 cm deep and 40-50 cm wide, fill them with heat-preserving materials such as sawdust, weeds, horse manure, and straw, then firm them down and cover with soil to seal the trench, so as to achieve the heat preservation effect.

5. Set up temporary heating measures

Two to three fan heaters with a power of 1600-2500 watts can be placed inside the greenhouse. The outlet direction of the fan heaters should not directly face the tomatoes; they can be angled toward the north wall instead, and the position should be moved once every 10-15 minutes. Smoking can also be used, but note that charcoal fires and coal stoves must not be used inside, to prevent carbon monoxide poisoning of people and plants.

6. Hang reflective screens

Hanging reflective screens not only increases the light inside the greenhouse and promotes fruit coloring in the greenhouse, but can also raise the temperature inside the greenhouse. The method is to hang plastic film or tin foil coated with a metal layer on the inner side of the back wall, hanging one meter every 2-3 meters. Hanging reflective screens reduces the wall's absorption of heat energy and can raise the greenhouse temperature by 2-3 degrees, while also increasing the light inside the greenhouse and promoting the coloring of tomato fruit.