How to manage summer vegetables? You need to know these rain-proof tips for polytunnels

Starting from July 24, the largest-scale, longest-lasting and hottest-feeling heatwave of the year so far has arrived.

Look at our vegetable growers: some are using high temperatures to seal and sterilize their polytunnels, some have just sown chili seeds and are preparing to germinate them, some have raised seedlings and are waiting for the Start of Autumn to transplant them, and some are digging lotus roots in the lotus ponds……Many farmers are still working in the fields under the blazing sun. Thank you all for your hard work!

We farmers are not afraid of hard work ourselves; we just hope these “precious vegetables” can grow strong and healthy and finally give a good harvest. So, the editor has put together some tips on vegetable management during hot and rainy summer weather, hoping they will be helpful to everyone.

How can you improve the transplant survival rate of summer vegetables?

In summer, temperatures are high, the difference between day and night temperatures is small, and water evaporation is great, so seedlings recover slowly after transplanting. To improve the survival rate:

First, adopt ridge cultivation or semi-high ridge cultivation, and take good drainage measures.

Second, use less chemical fertilizer or undecomposed organic fertilizer. For the base fertilizer, you can use bio-organic fertilizer or organic-inorganic compound fertilizer, applying 30-50 kg per mu, broadcast on the ground before ridging; before planting, apply 20 kg of biological bacterial fertilizer per mu in the planting holes, concentrated in the planting holes or under the ridges, and not in direct contact with the seedling roots.

Third, do not flood-irrigate when watering. After transplanting, water 2-3 times in a row for seedling recovery, watering in the early morning of the second day in alternate furrows or ridges; after rain, drain waterlogged areas promptly, and after midday thunderstorms, immediately water again with well water, that is, “watering the garden after waterlogging,” to reduce the harm of hot rain and reduce soil compaction.

Fourth, after the seedlings are planted, carry out intertillage and loosening of the soil 5-7 days later to increase soil aeration and inhibit excessive seedling growth.

What should you pay attention to when pruning and removing leaves in summer?

Take colored bell peppers as an example. In summer, temperatures are high and light is strong, so young colored bell pepper fruits and fruits in the color-changing stage are prone to sunscald. Reasonable pruning and leaf removal are effective measures to prevent sunscald. But note two points:

First: the leaves above the fruit should be “many but not crowded.”

To prevent sunscald, you must ensure there are leaves around the colored bell pepper fruits, especially the upper leaves. Follow the principle that the leaves above the fruit are “many but not crowded,” ensuring both ventilation between plants and sufficient light transmission. Do not remove the leaves above the fruit; even old leaves should be left on as much as possible. These leaves can serve as a “sunshade umbrella” for the colored bell pepper fruits and reduce the occurrence of sunscald.

Second: the leaves below the fruit should be “few but strong.”

Many vegetable growers remove all the leaves below the fruit when removing leaves, not leaving a single one, thinking that this not only reduces labor costs but also reduces nutrient consumption. In fact, this is unreasonable. After all the leaves below the fruit are removed, first, the plant leaves are greatly reduced, which lowers the formation of photosynthetic products and easily causes insufficient nutrient supply to the plant; second, without the shading of the lower leaves, direct sunlight around noon will cause the ground temperature around the roots to rise somewhat, which is not conducive to root growth. So do not remove all the leaves below the fruit; just appropriately keep one or two functional leaves.

How can polytunnels be made rainproof

Summer rainfall is concentrated. Because the spacing between polytunnels is small and they are relatively long, rainwater pours down from the plastic film, and before it can infiltrate, the rainwater accumulating on both sides has nowhere to drain. It can only enter the tunnel from both sides of the polytunnel, especially for low-lying polytunnels. Rainwater can easily pour in from both sides or the surrounding area, leading to severe root diseases.

Therefore, it is recommended to dig drainage ditches in the walkways between two polytunnels and at both ends of the polytunnel. The drainage ditches should be about 50 cm deep to ensure that rainwater can be drained promptly when it rains.

In addition, vegetable growers can also install rain-blocking films on both sides of the polytunnel side vents.

Some vegetable growers choose not to open the films on both side vents for ventilation when it rains. Although this can prevent rainwater from entering, the heat and moisture inside the tunnel cannot be released, and relying only on ventilation at the top for cooling is far from enough.

It is recommended to install another layer of plastic film on both sides of the polytunnel, with a film width of 70-80 cm, covering about 20 cm of the lower part with soil and hanging up the upper part; then install insect-proof netting according to the size of the ventilation openings on both sides. Generally, an insect-proof net width of 1.3 m is sufficient. In this way, when it rains, both sides of the polytunnel will have rain-blocking films, forming a simple drainage channel, avoiding rainwater pouring into the tunnel, preventing pests from flying into the polytunnel, and still allowing effective ventilation.

For connected large polytunnels, it is recommended to set up a “drainage gutter” in the middle of the tunnel roof to solve the problem of difficult drainage and enhance the rainproof capacity of the tunnel facilities.