The lighting rate of greenhouse is very important, which is related to the growth of crops. After all, sunlight is a necessary condition for crop growth. Once photosynthesis is lacking, crops cannot grow healthily and vigorously. So how can we improve the lighting efficiency of greenhouses?

1. Improve the structure of the greenhouse.

① Building materials. The shed surface is tightened with No. 8 galvanized iron wire, which not only saves building materials but also reduces shading, making it highly valuable for promotion. Use drip free film for greenhouse film; Ordinary film is better with polyethylene film. In addition, applying white coating to building materials and walls can increase reflected light and extend their service life; Appropriately increasing the height of the greenhouse can also improve the lighting conditions inside the greenhouse.

② The orientation and angle of the greenhouse surface. Adjustments should be made according to the greenhouse usage time, production purpose, and crop requirements for lighting conditions. A plastic greenhouse mainly cultivated in spring and autumn, with a smaller canopy angle (around 15 °) and a flat canopy surface to ensure equal distance and even distribution of transmitted light; In winter, it is required to have a larger angle of the canopy (around 25 °) and arch the canopy to facilitate natural lighting Shed width and back slope width. In winter production, the shed width is 6-6.5 meters and the horizontal distance of the back slope is 0.8-1 meters to facilitate lighting and insulation; Spring and autumn production, with a shed width of 8-9 meters and a horizontal distance of 0.5-0.7 meters from the back slope or without the back slope.

2. Reasonable layout.

When planting different types of vegetables in greenhouses, the principle of “high in the north and low in the south” should be followed to make the plants staggered and orderly, and minimize the phenomenon of mutual obstruction. When transplanting the same vegetable, strive for consistent seedling size to ensure neat plant growth and reduce shading between plants. It is better to plant in a north-south direction to allow it to receive sunlight as much as possible. In addition, strengthening cultivation management is also beneficial for improving the lighting conditions inside the greenhouse; According to reports, the cucumber rack adopts the practice of tilting the front row towards the south, standing the middle row upright, and tilting the back row towards the north, which can increase the light utilization rate by about 10%.

3. Keep the greenhouse film clean.

Water droplets and dust on the greenhouse film have a significant impact on the lighting conditions inside the greenhouse. According to observations, a layer of water droplets adhering to the greenhouse film can reduce the transmittance by 20 to 30%; After using the new film for 2 days, 10 days, and 15 days, the exposure to dust can cause the light inside the greenhouse to decrease by 14%, 25%, and 28% respectively. Therefore, water droplets and dust on the greenhouse film should be regularly cleaned and washed; Clear the snow promptly after snowfall to increase transparency and light intake. In addition, the insulation materials such as straw mats covering the outside of the greenhouse should be removed early and covered late, without significantly affecting the temperature inside the greenhouse, in order to Lighting area, extending lighting time; After sunrise, the greenhouse can be ventilated for half an hour to reduce water droplets on the film surface and increase light transmittance.

4. Reasonably remove the straw curtain.

On the premise of doing a good job in insulation work, it is advisable to remove the insulation straw curtain and delay the cover curtain in advance to extend the lighting time and increase the amount of natural light. Generally, the curtain should be removed 0.5-1 hour after the sun comes out, and then covered half an hour before the sun sets. Especially in hazy and rainy weather, it is necessary to appropriately remove the curtains to fully utilize the scattered light of the sun.

5. Choose drip free film.

In the production of drip free films, several surfactants are added to greatly weaken the affinity between water molecules and the film, and water droplets flow into the ground along the surface of the film without being produced. Choosing a drip free film canopy can increase the light intensity inside the canopy and raise the temperature inside the canopy.

6. Set up a reflective screen.

Assemble a 2-meter-wide and 3-meter-long reflective screen with polyester aluminum plated film, hang it on the upper end of the post behind the plastic greenhouse, and hang it down to the ground. In this way, the ground can be illuminated by 40% to 43%, the greenhouse temperature can be increased by 3-4 ℃, and the ground temperature can be increased by 1.8-2.9 ℃; And there has been an improvement in quality. In addition, laying silver ash film or aluminum foil on the ground can also increase the light intensity between plants, make fruits and vegetables color well, and prevent premature senescence of lower leaves.

7. Organize the plants well.

Timely field management such as pruning, branching, tying vines, and pruning old leaves is beneficial for the ventilation and light transmission conditions inside the greenhouse.

8. The film should be tightened and flattened without wrinkles or folds.

Generally speaking, it is easy to tighten the shed around noon.

9. The hanging rope should be colorless and transparent.

This can make the most of the light as much as possible.

10. Artificial supplementary lighting.

In the deep winter season or in plastic greenhouses with insufficient sunlight, artificial supplementary lighting is particularly important. The specific requirements and methods are: ① Supplementary lighting intensity. Artificial supplementary lighting requires high light intensity, preferably 1-3 kilolux; ② Light source. Research has shown that crops have a strong ability to absorb red and blue purple light. Therefore, three fluorescent lamps with a light source intensity of 40 watts are combined and irradiated at a height of 45 centimeters from the seedlings, with a light intensity of 3.0-3.5 kilolux. A high-pressure mercury lamp with a light source intensity of 100 watts is used at a distance of 80 centimeters from the seedlings, with a light intensity of 0.8-1 kilolux Supplement the light time. Winter supplementary lighting should be carried out after sunrise, generally for 2-3 hours a day, and stopped when the light intensity inside the greenhouse increases; Rainy and rainy weather can provide light all day long.