Gardeners – Start Your Sprinklers

Hot and dry may be just fine for picnics, ball games, and other outdoor activities. But for gardeners, hot and dry means its time to drag out the hoses and sprinklers.

Most gardeners are accustomed to watering flower beds and vegetable gardens. These plants require approximately 1 to 1 1/2 inches of water per week to maintain healthy flowers, foliage, roots, and fruits. In times of drought, established plants may tolerate 10-14 days between waterings but be aware that problems such as fruit cracking, blossom end-rot, and blossom drop will increase. Watering is most critical at pollination and fruit set time for most vegetable crops. Use a mulch where possible to conserve what moisture there is.

The best way to apply the water is by thoroughly soaking the soil with the prescribed amount of water in one application. This deep watering will encourage deeper root growth which in turn will be better able to withstand the drought. Frequent shallow watering encourages shallow roots which are more likely to succumb to heat and drying of the top soil. Sandy soil and containerized plants will need more frequent irrigation.

While many homeowners regularly water their lawns to keep them green throughout the summer, others prefer to allow the cool-season bluegrass to become dormant in the summer by withholding irrigation. In “normal” years, this strategy works just fine. But during severe drought, dormant lawns may begin to die if some water is not applied. Dormant bluegrass plants can generally last about 4-6 weeks without water. To avoid grass plant death while minimizing water usage, water deeply about once in 4-5 weeks. The grass will not green-up, but the crowns will stay alive, so that green-up can occur with the return of natural precipitation and more favorable temperatures.

Leaf scorch on trees and shrubs is very common in most summers, appearing as a browning along the edges of the leaves. While minor cases of leaf scorch are not terribly harmful to the plant, prolonged lack of moisture can spell disaster for landscape plants. Young and newly established plants are most susceptible to the dry conditions but even established plants may reach a critical point during prolonged drought. Branch dieback combined with eventual root death will make plants more susceptible to winter injury. Plants which were already under stress from other factors may succumb to severely dry soils.

Keep in mind that next year’s growth will be determined by buds that form this fall. Flower buds for many spring flowering and fruiting plants will also be developing this autumn. So even if your plants aren’t showing any symptoms now, the damage may become apparent later.

Watering of landscape and fruit plants should be aimed at where the roots naturally occur. While these woody plants do have some roots that grow very deep, most of the feeder roots that are responsible for water uptake occur in the top 18 inches of soil. Most of these feeder roots are concentrated below the dripline of the plant and beyond, not up close to the trunk. Allow water to thoroughly soak the target area by applying water at a slow enough rate to allow penetration rather than wasting water by runoff. Don’t apply the water any faster than 1 inch per hour. As with annual plants, a mulch will help prevent moisture loss due to evaporation.

The amount of time it takes to apply the proper amount of water depends on how much water pressure you have, the amount of space you need to cover, air temperature, and wind speed. You’ll need about 50 gallons of water to apply 1 inch of water to a 100 square foot area.

The ideal time to water is during the early morning hours ending by 8:00 am. This makes maximum use of water while allowing foliage to dry. Watering during midday when temperatures are high, sunshine is strong, and winds are brisk wastes substantial water. Watering in the evening or at night is convenient for many, but can make plants more susceptible to disease infection by providing the moisture that fungi and bacteria need to grow.

 


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