Summer heat is a real challenge for both experienced farmers and amateur gardeners. Climate change means that prolonged periods of drought and extremely high temperatures are becoming our new reality. If timely measures are not taken, scorching sunlight and a lack of moisture can destroy months of painstaking work. However, proper agricultural techniques, timely watering, and modern protection methods can save your garden beds, writes UNN.
Why summer heat is dangerous for plants
When the air temperature exceeds +30°C, serious physiological changes begin in plants that directly affect their viability. The main threats include:
Stunted growth and photosynthesis
At excessively high temperatures, the stomata on leaves close to reduce moisture evaporation. This blocks the intake of carbon dioxide, causing photosynthesis to stop. The plant stops growing and switches to "survival" mode.
Pollen sterilization
In many popular crops, such as tomatoes, peppers, and eggplants, pollen becomes sterile at temperatures above +32...35°C. This means that flowers drop without forming ovaries, and yields fall catastrophically.
Sunscald
Direct sunlight can literally burn plant tissue. White or yellowish watery spots appear on the fruit, which later dry out or begin to rot.
Overheating of the root system
If the soil is not protected, it can heat up to +50°C or higher. Under such conditions, surface roots die, and the plant loses its ability to absorb water and nutrients from the soil.
How to help plants in the heat
Helping plants during periods of extreme temperatures should be comprehensive. The main goal is to minimize stress and preserve vital moisture in the soil.
On hot days, it is strongly not recommended to remove suckers, prune, weed deeply around the roots, or transplant. Any wound on a plant under hot conditions heals very slowly and becomes an open gateway for infections.
After each watering, when the soil has dried slightly and is no longer sticky, carefully loosen the top layer of soil. This breaks up the soil crust and the microcapillaries through which moisture evaporates from the depths, while providing oxygen access to the roots. This technique is often called "dry watering." In hot weather, plants absorb macronutrients less effectively. Excess fertilizer—especially nitrogen-based fertilizer—combined with a lack of moisture can simply burn the root system.
Watering the garden in hot weather
Proper watering is the foundation of a garden's survival in summer. Improper moisture management can cause more harm than the drought itself.
Plants should be watered exclusively early in the morning (before 8:00) or late in the evening (after 19:00, when the sun sets). Morning watering is better for crops prone to fungal diseases because the leaves have time to dry before nightfall.
It is strictly forbidden to water garden beds with ice-cold water from a borehole or well. Thermal shock causes ovaries to drop and sharply weakens immunity. The water should be left to stand and warmed in the sun (approximately +20...25°C). Frequent shallow watering encourages roots to develop in the very top layer of soil, which dries out fastest. Water less frequently (for example, 1–2 times a week), but abundantly, so that the soil is moistened to a depth of 20–30 cm. This will force the roots to grow deeper in search of moisture.
Drip irrigation is the ideal option for a hot summer. Water is delivered directly to the root zone in measured amounts, which significantly conserves resources and prevents moisture from getting on the leaves.
Protecting plants from the heat
To save plants from direct sunlight and overheating of the soil, use the following agricultural techniques:
Mulching is the simplest and most effective way to protect the root system. A 5–10 cm layer of mulch (straw, hay, seedless grass clippings, peat, sawdust) retains moisture in the soil, prevents weed growth, and keeps the soil from overheating.
Shade nets diffuse direct sunlight and reduce the temperature above the garden bed by 5–10 degrees. For vegetables (tomatoes, cucumbers, and peppers), nets with a 45–60% shading level are best suited.
Spunbond (agrofiber) reflects sunlight exceptionally well. It can be draped over hoops above the beds, creating a comfortable, breathable microclimate.
Nurse-crop plantings — plant tall plants to shade shorter ones. For example, rows of corn or sunflowers planted on the southern side will create natural dappled shade for peppers, cucumbers, or squash.
How to Treat Plants in Hot Weather
Under conditions of heat stress, plants need support at the cellular level. Special preparations can help:
Adaptogens and Anti-Stress Agents
Preparations based on amino acids, phytohormones, or seaweed extracts (for example, Epin, Zircon, Megafol, Aminostar). They help plants recover more quickly after heat shock and boost their immunity.
Calcium Preparations
In hot weather, calcium absorption from the soil drops sharply, which is the main cause of blossom-end rot in tomatoes and peppers. Foliar feeding (spraying) with calcium nitrate or calcium chelate will help save future fruits.
Biological Preparations
Stress makes plants vulnerable to pests (the spider mite, in particular, reproduces especially quickly). Use safe biological fungicides and bioinsecticides for regular preventive treatment.
Important: Carry out any spraying exclusively after sunset! Water droplets on leaves under direct sunlight act as microlenses and cause severe burns to plant tissues.
How to Preserve the Harvest Until the End of the Season
At the end of summer, the heat may persist during the day, while nights become cooler, creating new challenges. To preserve the fruits until the end of the season, follow several rules:
Timely Harvesting
Do not leave ripe vegetables on the plants. Overripe fruits draw moisture and a tremendous amount of nutrients to themselves. Regular harvesting stimulates the formation of new ovaries and the growth of young fruits.
Disease Prevention at the End of Summer
Fluctuations between daytime and nighttime temperatures in August trigger heavy dew. This is an ideal environment for the development of late blight and powdery mildew. Ensure good air circulation around the plants by removing the lower leaves, and carry out preventive treatments (for example, with Fitosporin or Trichodermin).
Pinching the Growing Points (Topping)
Three to four weeks before the expected cold weather, pinch out the tops of tall-growing tomatoes, peppers, and eggplants and remove all new flowers. They will no longer have enough time to produce a harvest, but will take strength away from the fruits that are already developing.
Controlling Moisture Toward the End of the Season
When the daytime heat begins to subside, gradually reduce the frequency of watering. Excess moisture at the end of summer makes fruits watery, worsens their flavor, causes cracking, and significantly shortens their storage life.
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