Managing Turf Drought
From proper irrigation to mowing to fertilization here are some helpful ways to manage drought that can help protect plants while conserving water.
March 6, 2018
Most turfgrasses are resilient and will recover from drought conditions with minimal injury if proper management practices are implemented prior to and after the onset of stress. Turf needs proper amounts of moisture and nutrients to aid in the recovery process. Proper cultural practices will also aid in drought tolerance and recovery.
Cool season grasses perform best in temperatures between 60 degrees and 75 degrees Fahrenheit whereas warm season turf performs well at temperatures above 80 degrees Fahrenheit. Low soil moisture and increased temperatures between the months of June and August are very stressful to cool season turf. Due to low soil moisture the first signs of dormancy will be a loss of color in the turf. The turf will take on a bluish-gray color and become very dry and brittle. Applying as little as one inch of water per week can help the turf to retain color. Turfgrass can usually survive 4-5 weeks of dormancy with minimal damage. Dormant grass will not recover if the rhizomes roots and crowns dehydrate.
Proper irrigation practices are critical during times of drought. It is important to water deeply and infrequently opposed to lightly and frequently. Watering deeply helps the water to penetrate the soil allowing more moisture availability and retention. Watering lightly and frequently keeps the moisture on the surface causing quicker evaporation and shallow root development. Water should be applied in the early morning hours (between 5am - 9am). Avoid irrigation in the afternoon due to rapid evaporation and heat build up. Also avoid irrigation in the evening due to the promotion of disease pressure. In times of water bans one half inch of water every one to two weeks may be enough to keep the crown rhizomes and roots hydrated.
Certain precautions should be made when mowing turf during drought conditions. Always be sure that mower blades are sharp to avoid tearing the turf. Turf mowed with dull mower blades will take on a brownish-gray cast soon after mowing because of moisture loss through the torn tip of the grass blades. Do not remove more than one third of the new growth in any one mowing. Removing too much top growth will cause a reduction in root mass and will not enable the plant to retain enough moisture. Alternate mowing patterns to avoid soil compaction caused by tire tracking. These practices will help control stress during drought conditions, but should be practiced the entire season.
Proper fertilization will help the turf become more stress-resistant and allow the plant to recover more quickly from the stress. Providing the turf with adequate potassium prior to drought conditions will help make the plant more stress-, insect- and disease-resistant and enable quicker recovery in the fall. Using slow release nitrogen will help keep the plant growing during drought periods and help the turf maintain its color. Avoid quick release nitrogen before and during drought periods. This practice can flush top growth and can predispose the plant to injury much quicker due to an out of balance root to shoot ratio (root growth to top growth ratio). It is best to use a 1:1 ratio of nitrogen to potassium to improve stress tolerance within the plant.
Hydrophobic (water repellent) soils are found in many areas where turfgrass is grown. The use of long-term residual wetting agents will help alleviate problems associated with localized dry spot from hydrophobic soils for up to an entire growing season. Long-term residual wetting agents, like LESCOFlo Ultra, work best when applied preventively prior to moisture stress. Shorter residual wetting agents, such as LESCOWet Plus, also help alleviate problem areas from localized dry spot, but may need to be applied on a more frequent schedule. It is critically important that both long- and short-term residual wetting agents be incorporated into the soil with irrigation for the products to become effective in the alleviation of localized dry spot conditions. Keep in mind that wetting agents do not assist in water retention. They allow for more efficient use of the available water by reducing the surface tension and allowing water to penetrate the hydrophobic layer of soil.
These practices, combined with other cultural practices such as aerification for thatch reduction, will help turf during stressful conditions. Turf should be re-evaluated at the end of August and preparations made for overseeding or sodding areas that do not recover.