Is my grass dead from the flood?

Published 5:54 pm Thursday, October 11, 2018

As we stare down another major storm event headed our way, I have been fielding calls this week about dying turf from the last event. There are many issues to consider: was the turf flooded, what was the duration of the flooding, what type of soil texture do you have, what type of grass do you have, was the flood water salty?

The answers to all of these play a part into building an answer of what to expect. Think about plants and what plants need to grow. Plants need sunlight, water, oxygen and nutrition. If you were able to attend last week’s “What You Need to Know So You Can Grow” class on soils, you would know that plants get water, oxygen and nutrition from the soil. The ideal soil is comprised of 45-percent mineral soil, 25-percent water, 25-percent air and 5-percent organic matter. The texture of the soil, sand, clay, silt or mixture thereof, determines how quickly the soil drains. Larger particle size, such as sand, drains much quicker due to the large pore size in between the soil particles. Smaller particles, such as clay, pack much tighter, cutting down on pore size and making drainage much slower. When soil is saturated, water fills all of the pore space, displacing air and robbing the roots of plants of oxygen. So, if your lawn was flooded for any amount of time, you must consider texture size of your soil in determining how long the soil was flooded and remained saturated. This combination is how long your grass, trees, flowers, etc. went without oxygen.

The longer your plants went without oxygen, the more stressed they are going to be. Plants vary in their hardiness and response to being flooded. For example, Bermuda grass can be submerged and will come back from nearly all flooding; centipede, on the other hand, may not come back at all. The depth, clarity and temperature can have much to do with survival as well. If the flood water was deep (greater than 12 inches) or cloudy with soil particles or debris, it is much worse on turf than if it was clear. If water temperatures were higher, near 80°F, flooding will be much more damaging than 50°F water temperatures.

What can you do to help your lawn recover? Remove any soil deposition from flooding as soon as possible. Use a blower to remove debris/silt under 1-inch thick — this will assist the lawn in drying. The quicker the grass dries out, the more you can protect from disease in your turf. Mow your lawn as soon after the flood as you can without further compacting soil (i.e. leaving tracks). Significant compaction can occur from flooding. Aerate your soil to alleviate compaction and add oxygen to the root zone. If soils were inundated with salt water from storm surge, aerating will also assist in flushing salts from the root zone.

If you have found yourself in this situation, call an Extension Master Gardener Volunteer or your local horticulture agent for more information.

Register now for the “What You Need To Know So You Can Grow” educational series taught at the Beaufort Extension Center this October to learn more about Soil, Growing Vegetables, Growing Fruit, Turf Management, Diseases and Pests of Ornamentals. This series will be taught on Thursdays beginning Oct. 4 from 6 p.m. to 8 p.m., and conclude on Nov. 1. The cost is $10 per class ($15 at the door); those attending all of the classes will earn the Blacklands Area Friends of Horticulture “HomeGrown” certification and a free gardening guide published by the Extension master gardener volunteers in Beaufort County. To register, contact Sam Bowden at the Beaufort County Extension office by calling at 252-946-0111.

This series answers real questions from eastern North Carolina. If you have a question to submit, please email to Gene Fox at Learn more on Facebook at the Blacklands Area Horticulture page or visit the Extension Office located at 155 Airport Road!

Gene Fox is the area agriculture and consumer horticulture agent for Beaufort, Hyde, Tyrrell and Washington counties.