All about the temperature in the greenhouse for cucumbers

All about the temperature in the greenhouse for cucumbers

Homeland cucumber – subtropical and tropical India. To maximize your yields, it will be useful to know everything about the greenhouse temperature for cucumbers, especially if they are grown commercially.

All about the temperature in the greenhouse for cucumbers

The importance of temperature

Different garden crops have different requirements not only for specific temperature indicators, but also for the strictness of their observance. For instance, the tomato is relatively hardy, and therefore its adaptive capabilities are higher. The temperature in the greenhouse for cucumbers is a key factor in their cultivation. It directly affects fruiting.

Nighttime temperatures are just as important as daytime temperatures. For example, the interval of desirable night temperatures for a cucumber is +18 … +22 ยฐ ะก. If you stick to the highest value in this range, the plant will more actively pour fruit, the crop will return faster.

If you maintain the lower value, + 18 … + 19 ยฐ ะก, the bushes will redirect forces to the roots and shoots – in this way, fruiting can be extended for several weeks.

All about the temperature in the greenhouse for cucumbers

Low temperatures are fatal for cucumbers, and overheating (during the day – above + 30 ยฐ C, at night – above + 24 ยฐ C) starts the aging process: the plant is quickly depleted.

Optimal performance

Air temperature required in different periods:

  1. germination of seeds in closed containers – +25 … + 28 ยฐ ะก;

  2. barely appeared seedlings grow best at + 20 … + 25 ยฐ ะก;

  3. growing seedlings is permissible at + 20 … + 22 ยฐ ะก;

  4. flowering period – + 25 … + 28 ยฐ ะก;

  5. harvest ripening – + 25 … + 30 ยฐ ะก.

All about the temperature in the greenhouse for cucumbers

It is not necessary to regulate the temperature to the nearest degree. It is enough to approximately follow these ranges. Contrasting temperatures are unfavorable for both seedlings and adult plants.

It is important to remember: the average comfortable temperature for the culture is + 20 … + 22 ยฐ ะก.

All about the temperature in the greenhouse for cucumbers

The minimum indicator, including at night, is + 16 ยฐ ะก. During the formation of the ovaries, a decrease below + 19 ยฐ C is undesirable – the cucumber will cease to tie future fruits.

The maximum comfortable temperature for a cucumber is + 30 … + 35 ยฐ ะก. At + 35 ยฐ C and above, the plant will stop forming ovaries, and the existing cucumbers will begin to dry.

The critical range for cucumber is +10โ€ฆ+15ยฐะก. Plants do not freeze, but stop growing. And at +10ยฐC growth stop may be irreversible if it lasts longer than 3-5 days. Complete death of plants occurs at +8 … +9 ยฐ C for two or more days. A short-term drop to +5ยฐC will kill the plants in 1 day.

All about the temperature in the greenhouse for cucumbers

In unheated greenhouses in some regions of the Russian Federation, such temperatures are possible even at the beginning of summer. Regular inspection will help prevent the death of plants. If the leaves are slightly wilted, sagging in the morning with “rags”, then the night temperature is too low.

The soil for planting should also be warm – about + 18 ยฐ C, but not lower than + 16 ยฐ C. The upper favorable limit for the soil is + 35 ยฐ C, at this temperature the roots slow down their work, the leaves begin to wither.

All about the temperature in the greenhouse for cucumbers

All about the temperature in the greenhouse for cucumbers

Seeds are planted in the soil, which has a temperature of + 24 … + 28 ยฐ ะก. These are the best conditions for friendly seedlings. The lower comfortable limit is + 16 … + 18 ยฐ ะก. Seedlings may begin to appear at +14 … +15 ยฐ C, but germination will be very slow and uneven, and future plants will be weak and unproductive. If you have to plant in cold conditions, you need to provide at least bottom heating. Soil temperatures below +12ยบะก for seeds will be detrimental – they will simply become moldy and then rot.

For the growth of cucumbers, the soil temperature is maintained in the same ranges. The soil should be warmed up to at least + 16 … + 18 ยฐ ะก both day and night.

All about the temperature in the greenhouse for cucumbers

The resistance of the plant to cold air strongly depends on the temperature of the soil. If the soil is not colder than + 16 ยฐ C, then a young plant is able to withstand even a daily decrease in air temperature to + 5 ยฐ C without any consequences. On warm beds, cucumbers sometimes even withstand a drop to + 1 ยฐ C for a couple of days.

Before planting in a polycarbonate greenhouse, it makes sense to harden the plants. 10 days before the day of disembarkation, the air temperature is reduced to + 16 … + 17 ยฐ ะก. Reduce watering 3 days before planting. Unhardened seedlings can die if the soil temperature drops to + 15 ยฐ C.

All about the temperature in the greenhouse for cucumbers

Fruiting plants require the same soil temperatures, but are slightly more hardy.

Water for irrigation should be warm, about the same as the soil.

When and how to regulate?

The critical period usually occurs in late May – early June. Young plants are less hardy and die more often than adults. In many regions of the Russian Federation, late spring is a period of warm, fairly stable weather, which tempts gardeners with the appearance of the opening of the planting season. But there is a possibility of short-term cold weather. For example, in the Urals, the air temperature can drop to 10ยฐC.

All about the temperature in the greenhouse for cucumbers

They regulate the microclimate with the help of transoms and doors, film screens. While the plants are not tied up, they can be covered with non-woven materials.

Doors and vents need to be opened and closed on time. So you can not only protect plants from extreme temperatures, but also align the night-day regime. The time for opening and closing must take into account that the effect will be delayed. In late spring – early summer, the windows should be closed no later than 3 pm, in the middle of summer, when it is very hot, no later than 6 pm. For gardeners who do not have time for this work, there are machines with temperature sensors. Their cost varies between 900-3000 rubles.

All about the temperature in the greenhouse for cucumbers

It is better to insert transoms in a continuous row on two sides of the roof, but this design is considered too overhead.

To increase the temperature, any method that creates a layer of insulated air is suitable. Most often, a regular film is enough.

If the forecast promises disastrous weather for cucumbers, you can organize a mini-greenhouse in the greenhouse from the simplest frame and perforated film.

All about the temperature in the greenhouse for cucumbers

The soil is protected from temperature extremes and hypothermia with mulch. Let’s describe the best options.

  1. Black film with perforation and holes for cucumber seedlings. The only negative is that in the bright sun such a film can overheat.

  2. A transparent film without holes is used for seed germination. It allows you to create a mini-greenhouse – seedlings will appear in a few days. Then it is changed to dark. The transparent film retains up to 4ยฐC during the day and up to 8ยฐC at night.

  3. Peat, finely chopped straw, hay, grass, sawdust, needles. All these materials are used only if the seedlings are planted high. The method simultaneously allows to equalize the humidity regime.

All about the temperature in the greenhouse for cucumbers

The heat is not as critical as the cold, but it can also be dangerous. Fans are installed to combat overheating. But there is a nuance – cucumbers do not tolerate drafts. Therefore, greenhouses house units operating with large volumes of air and low speeds. It can also help to install an exhaust fan, which avoids the collection of condensate on the walls of the greenhouse and waterlogging of the air. Ordinary household fans are suitable for occasional use. At the peak of solar activity, 2 fans installed on the central path of the greenhouse reduce the temperature by 3โ€“6 degrees in 30โ€“40 minutes.

All about the temperature in the greenhouse for cucumbers

An open window can lower the temperature in the greenhouse by 12ยฐC, but this may not be enough in extreme heat. The end walls of greenhouses are sometimes partially or completely covered with a softer material than polycarbonate. It can be spunbond, greenhouse mesh, ordinary film. On hot days, they are simply folded and secured, completely opening up access to air.

You can use any method related to air humidification.

  1. Normal fine water spray. Lowers temperature by 3-4ยฐC.

  2. Sprinkling of the walls of the greenhouse. In extreme heat, this technique can lower the air temperature by 13ยฐC.

  3. Watering paths in the greenhouse.

  4. Additional watering has a positive effect on cucumbers in the heat. Moisturize them not only in the evening, but also in the morning. Then the greenhouse is ventilated to avoid waterlogging of the air. This indicator should be maintained within 70%.

All about the temperature in the greenhouse for cucumbers

On average, additional humidification lowers the air temperature by 8ยฐC.

To equalize the temperature, dark-colored cans of water are used. During the day they are placed in the bright sun, at night they are brought into the greenhouse. They accumulate solar heat, at night they gradually release it into the air. You can install a barrel of water in the greenhouse, on a hot day the water heats up quickly and partially evaporates, cooling the air in the room. The warm water can then be used for irrigation.

All about the temperature in the greenhouse for cucumbers

To eliminate overheating of the greenhouse in the bright sun in the middle of summer, the following methods are used.

  1. Raising the greenhouse on supports for ventilation from below (only for small greenhouses, without foundations, and in calm areas).

  2. Shelter with a light-colored cloth, shading net, non-woven fabric. The shelter is fixed with ordinary bricks, stakes, cords with weights.

  3. Internal roll-up spunbond screens. They are hung on rows of wire from the inside of the greenhouse. Plus, they won’t be blown away by the wind. Cons – limit the access of light to plants (although this is not so critical – light still penetrates through the walls of the greenhouse).

  4. External screens made of covering materials.

  5. Screens made of plastic or wood. They resemble blinds, conveniently fold and unfold.

  6. Placing or hanging bottles of frozen water in the greenhouse.

  7. Spraying with a solution of chalk (1 cup of chalk per 10 liters of water), unlike water-based paint, this whitewash is easily washed off. Spray so that the result is stripes, not a solid spot.

All about the temperature in the greenhouse for cucumbers

You can vary the temperature for cucumbers in a greenhouse by combinations of various methods. In many cases, the issue can be resolved even at the stage of choosing a greenhouse. For example, in Siberia it makes no sense at all to take structures without vents. The climate is sharply continental, with contrasting temperatures. The scorching sun in June-July is so difficult to compensate without a high-quality cooling system that the harvest will eventually be less than on warm beds in open ground.

All about the temperature in the greenhouse for cucumbers

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Anna Evans

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