Prolonged droughts and heatwaves are expected to become more common in the coming decades, with parts of the US already experiencing what scientists call a “megadrought.”
Drought is a period of unusually dry weather that lasts relatively long. In addition to wider social impacts, such as potential damage to crops and water scarcity, drought can also have devastating effects on garden plants.
So how can you care for your garden in these dry and hot conditions?
How does drought damage plants?
Drought stress occurs when the loss of water through leaves exceeds the ability of a plant to draw water from its roots, explained Lucy Bradley, a horticulturist at North Carolina State University Extension. newsweek,
It interferes with many important processes including photosynthesis (the conversion of food into energy); Transpiration (movement of water through the plant and evaporation from some parts, which helps to cool it); “Turger” pressure that makes the plant stiff and hard; and the growth of root hairs, which draw water and nutrients from the soil.
Perhaps the most significant effect of drought on plants is a reduction in photosynthesis, which is the process through which plants make food from sunlight, providing energy (in the form of sugar) to grow, produce flowers and fruits, and reproduce. it happens.
“Extended drought can lead to a complete collapse of the photosynthetic machinery and take a long time for plants to rebuild their roots and internal systems,” said horticulture educator Vijay Pandian in the University of Wisconsin-Madison Division of Extension. newsweek,
“This can cause long-term effects … and the symptoms of the effects of drought often continue. [the] next few years,” he said.
In the short term, drought can cause leaf wilting and wilting, loss of leaves and death of branches, among other symptoms, according to Heidi Krautsch, a horticulturist at the University of Nevada, Reno Extension.
“Over time, drought can weaken plants, making them less productive and more vulnerable to pests and diseases,” explains Crash. newsweek, “Drought-affected plants can pose a fire hazard even in areas prone to wildfires.”
What can you do to protect plants in drought?
It’s important to manage water effectively, according to Christine Lang, a horticulturist at South Dakota State University Extension.
“Once the plants have been in the garden for several weeks and have established roots, water deeply one to two times a week to completely saturate the soil and encourage deeper roots of established plants each time. More beneficial than light water during the day,” Lang pointed out. newsweek, Deep roots help plants survive drought conditions.
“When watering, it is important to water the soil versus wetting the leaves of the plants, which can actually contribute to the spread of some plant diseases,” Lang said.
During drought conditions, watering is recommended early in the morning when the air temperature is cool to ensure that water can reach the roots of the plants.
“Avoid watering when it is windy, as wind increases evaporation of soil moisture and makes spray irrigation less efficient,” Crash said.
It may also be beneficial to use soaker hoses or install a drip irrigation system where possible. “Drip irrigation applies water directly to the soil where the roots are and minimizes excess water runoff on unpaved or paved areas,” Crash said.
According to Pandian, trees should be thoroughly soaked once or twice a week. Meanwhile, newly planted trees and shrubs (between 1-3 years old) need to be watered twice a week to a depth of about an inch (about 0.6 gallons of water is needed to cover an inch deep per square foot). it occurs).
You can use a long screwdriver or soil probe to test the depth of water movement in the soil.
Gardeners who have plants in containers, hanging baskets, and pots may or may not need water every one to two days, depending on the size of the container, Lang said.
Applying a layer of material over the surface of the soil, a technique known as mulching, can also be beneficial. “Massing the soil surface of the garden with organic material such as straw or wood chips can help retain soil and keep the soil surface cool around the plant,” Lang said. “It also reduces competition from weeds which becomes even more important during drought conditions.”
Erecting temporary structures to provide shade around heat sensitive plants can also help prevent evaporation of excess water from the leaves.
“Heat-damaged leaves appear progressively red or brown and become dry and brittle to the touch,” Crash said.
Taking care of plants while away
If you’re away from home for several days, try moving the potted plants to a more shady area if you don’t have someone to water them with, Lang said.
During dry conditions, it is also important to remove all competition for desired plants, which may include weeds; Weak, diseased or stressed plants that are past their prime; and annuals that can be replaced easily, Bradley said. Also, don’t encourage plant growth by fertilizing or pruning: “Growth taxes the entire plant and new growth is weakened,” she said.
Fertilizing drought-stressed trees and shrubs often stimulates more foliage at the expense of root growth, according to Pandian, who also recommended avoiding unnecessary transplants.
When it comes to lawn, don’t worry too much if it begins to go dormant — noticeable by a sawdust — in the extreme summer heat. Most lawns can survive two to three weeks of dormancy and will turn green again when temperatures cool.
“Small areas that do not recover can be sown more in the fall (unless drought is still present) or in early spring,” Crash said. “One option is to learn to accept a less-than-perfect lawn (as Mother Nature intended). Don’t fertilize lawns or other landscape plants during droughts.
“For future drought years, consider replacing unnecessary lawn areas with plants that can better handle heat and low water conditions.”