What measures are there to prevent freeze damage to greenhouse flowers in winter?

In winter, the northern regions experience a lot of wind and snow, and at this time flowers in the northern regions begin to enter the greenhouse management stage one after another. The temperature inside the greenhouse is low, and the room temperature is generally low. If it is sealed for a long time, combined with poor management, freeze damage and wind damage of varying degrees are likely to occur. In mild cases, flower growth is affected; in severe cases, the flowers die. Attention should be paid to avoiding this.

(1) Remove the straw mats at the right time. When temperature conditions permit, uncover as early as possible and cover as late as possible to promote photosynthesis in the flowers. In deep winter, on sunny days, generally remove the straw mats in the morning when sunlight falls across the entire greenhouse surface; at this time the temperature inside the greenhouse is generally not lower than 18°C. On cloudy or overcast days, light is weaker, but the straw mats should still be removed at the right time to let scattered light enter. On one hand, this can raise the temperature; on the other hand, because scattered light contains more blue-violet light, it is beneficial to photosynthesis. Never leave the straw mats in place for a long time, causing the greenhouse to become dark and cold and the temperature to drop sharply.

(2) Add covers. At night, set up small tunnels inside the greenhouse and add straw curtains. Adding straw mats or corn stalks around the greenhouse at night can increase the temperature by 1°C~2°C. Adding a thin mat on top of the original straw mats can raise the greenhouse temperature by 2°C~3°C. Covering the original straw mats with a layer of film can not only block wind, but also prevent rain and snow from wetting the straw mats, thereby reducing heat loss caused by water evaporation. For flowers planted in the ground, plastic film mulching can also be carried out; after mulching, the soil temperature can be increased by more than 1°C.

(3) Water pool heat preservation. Dig a water storage pool every few meters in the center of the greenhouse, lay plastic film on the bottom of the pool, then fill it with clear water, and then cover the upper part of the pool with a layer of transparent film (to prevent water evaporation in the pool from increasing the air humidity inside the greenhouse). Because water has a high specific heat, it can absorb heat at noon (when the temperature is high) and release heat at night.

(4) Heating for warmth. In extremely cold weather, a stove can be added inside the greenhouse or heating can be turned on, but when using stove fire for heating, attention must be paid to preventing gas poisoning in the flowers. A chimney should be installed to discharge the gas outside the greenhouse. Be careful not to burn firewood or grass inside the greenhouse to raise the temperature, because the smoke released when firewood and grass burn is extremely harmful to flowers.

(5) Apply more fertilizer. Add heating materials such as horse manure and chopped grass into the greenhouse to raise the ground temperature. The decomposition of organic fertilizer can release heat. Applying an appropriate amount of organic fertilizer and phosphorus-potassium fertilizer can not only improve the soil aggregate structure, raise the soil temperature, and provide nutrients for the flowers, but also enhance the cold resistance of the flowers.

(6) Cover with plastic film or small arched tunnels. In greenhouses using high-ridge cultivation, a layer of plastic film can be covered on the high ridges, generally increasing the ground temperature by 2°C~3°C; for flat-bed cultivation, small arched tunnels can be set up to raise the ground temperature.

(7) Dig cold-proof trenches. Dig a trench on the south side outside the greenhouse and fill it with insulation materials such as horse manure, weeds, and straw, which can prevent ground heat from escaping outward and raise the ground temperature in the southern part of the greenhouse.

(8) Smoke around the greenhouse. Before a cold wave arrives, light fires around the greenhouse to produce smoke, which can prevent heat around the greenhouse from radiating into the high air and reduce heat loss.

(9) Spray antifreeze. Before the temperature drops, spray the stems and leaves of the plants with a 400~700 times dilution of antifreeze solution, which can play a role in cold prevention and freeze resistance.

(10) Spread plant ash. Plant ash is gray-black and has a strong heat-absorbing capacity. After evenly spreading it on the greenhouse floor, it can generally raise the ground temperature by 1°C~2°C.

(11) Clean the greenhouse film. Promptly and thoroughly remove dust, dirt, and accumulated snow from the greenhouse film, which can increase light and raise the greenhouse temperature.

(12) Double-layer film covering. Install another layer of film below the anti-drip film. Because there is air between the two layers of film, the temperature inside the greenhouse can be significantly increased.

(13) Hang reflective curtains. Hang polyester aluminized film on the north side of the greenhouse, which can increase light inside the greenhouse and raise the greenhouse temperature by 2°C~3°C.

Freeze damage to greenhouse flowers occurs from time to time in winter. Farmer friends should take preventive measures well, control the temperature inside the greenhouse, prevent greenhouse flowers from freezing, and reduce losses.