If your property is currently under a water restriction or is just in a period of heat and drought, it’s prudent to implement some commonsense practices when watering lawns, vegetable gardens and landscape plants. For various reasons, some communities restrict water application. Regardless whether your local authority has placed limits on watering amounts and frequency, several techniques can be helpful.
First, it’s important to realize that heat and drought effects are not the same. As temperatures increase, the growth rate of plants also increases. However, once air temperatures reach into the high 80’s, the growth rate begins to slow. The influence of soil temperature is similar, with root growth slowing or even ceasing as it reaches 85-87 degrees. During periods of high air and soil temperatures, photosynthesis (production of sugars and carbohydrates) slows significantly, while respiration (the use of sugars and carbohydrates by the plants) continues, which depletes the plants of food reserves and weakens them overall.
In addition, high temperatures can also cause extreme water loss from leaves and stems. This occurs when the plant transpires (release of water vapor to the atmosphere to cool itself) more than it absorbs through the roots. Evaporation of water from the soil between plants further reduces the amount of water available to the plant.
The second consideration is the extended condition of periods of dryer than adequate soil moisture also called drought. High temperatures combined with drought influence the plant with two factors that are related and cause additional stress. Along with equipment limitations, extended heat and drought often cause municipalities to impose voluntary or mandatory water restrictions.
Practical Guidelines:
During periods of heat, drought and water limits, it’s important to use water responsibly. These strategies should be utilized:
* Prioritize plantings to be watered according to the interests of the property owner in various categories such as perennial/annual beds, trees/shrubs, containers, vegetable gardens, fruit trees and lawns. When water supplies are tight, it’s usually not realistic to water all plants in the landscape.
*Overall, the roots of high priority plants should be kept moist, not soggy or dry. Always check soil moisture before watering. Use a long screwdriver, piece of ree-bar or cut-off golf club; if it slides in easily and the metal is moist, wait a day and check again.
*Keep in mind that heat and drought stress cannot be overcome with extra water. Creating soggy soils with extra water is counterproductive; roots growing in overly wet soils will die due to a lack of oxygen.
*Avoid fertilizer applications for plants under heat and water stress, or any other type of stress. Also, avoid applications of vitamins and Superthrive.
*Apply water low to the ground to limit off target movement. Soaker hoses, drip irrigation systems, spot watering devices are best. If sprinklers are needed for turf, avoid oscillating types that place water high in the air when it is easily carried away from the grass plants.
*If the lawn is a priority, identify the turf species. Consider allowing bluegrass and buffalograss to go dormant in periods of drought. Tall fescue does not have the capacity to recover after a period of drought, so it must be watered at least every 2 weeks to avoid the need for reestablishment.
*Water in the morning when less water is lost to evaporation and more is available for absorption by plants.
*Check soil moisture frequently, especially for container gardens/patio planters, hanging baskets and vegetable gardens that can dry out quickly in hot, windy weather. Consistent moisture is especially important for these plants.
*Remember that the roots of recently installed plants have not expanded much and are likely to be similar to container gardens, with a root mass that dries out quickly.
*Covering the soil around vegetables, perennials, annuals and trees/shrubs with wood chips, cocoa hulls and leaf mold can help hold water in the soil by reducing evaporation. Use an inch for veggies and 2-3 inches for the others.
*For plants in containers, move them to a shady spot during periods of high temperatures. When less light is received by the plant and container, the temperature around them is cooler and moisture loss is reduced. For high priority plants that are not moveable, consider shading them with shade cloth, screening and white bed sheets.
