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Tips to help lawns recover from flood damage




We had a LOT of rain in Maryland yesterday, and all we can think about is how soggy your lawns are right now! As floods become more common, so has the chore of recovering from their damage. Whether the water rises from rivers or oceans or falls from the sky, homeowners need to salvage or replace their lawns after it recedes.


If Mother Nature throws a watery hissy fit and floods your lawn, expect to expend some of your own liquid, in the form of breaking a sweat. Lawn and landscape repair isn’t easy. And compared to other items on a homeowner’s post-flood must-do list, it’s not a "top priority." But once you work your way down to it, here’s how to help your lawn recover from a flood.


Flooded lawns: Two types

Lawn damage due to flooding comes in two types:


Direct damage: When water inundates your lawn for an extended period, it can die from a lack of oxygen. Grass submerged more than six days has a low chance of survival, especially if temperatures are high and heavy silt coats the grass.


Secondary damage: Even if the grass survives the flood, sediment buildup can lead to fungal diseases, algae, moss growth, and an infestation of weeds. If you have suffered a severe, extended flood, your lawn likely will show a mixture of direct and secondary damage.


Temperature, Light and Depth

The biggest factors that determine how well your lawn survives the flooding are water temperatures and the depth of the water.


Deep water and hot weather are bad news.


If the leaf tissue remained above the water line, it is likely to survive. If submerged, survival rates go down.


Grass hit with flooding during the cooler months of the year has a better chance of survival than when flooding occurs during the warmer months. Turf that remains flooded for more than several days, especially when it is hot, can rapidly decline due to lack of oxygen and light. Substantial turf loss can be expected after four days of continued submersion. In fact, it can take only a couple of days for grass death when water temperatures are 80 degrees Fahrenheit and warmer. Grass can still die when temperatures are cooler, primarily due to the lack of oxygen.


What flood-damaged grass looks like

When short-term flooding occurs during the cooler months while the turf is dormant, the turf may not lose its color. However, when flooding occurs during the warmer months the turf may turn brown or yellow, as the turf has lost its ability to uptake nutrients due to lack of oxygen in the soil.


You will have to play a waiting game to see if the grass revives once the water recedes and the area dries out. The best course of action is waiting several weeks after the floodwaters leave. No new green growth from the lawn means it died and needs replacement.


To determine if your grass plants were killed by the floodwaters, pull up a few plants from the area and cut a horizontal cross-section through the crowns. If the crown section remains white and firm, the plant has survived the flooding. However, if the section is mushy and brown, the plant is dead and new plantings are required.


Post-flood lawn clean-up steps

Step 1: Get the big stuff

Once you can walk your lawn to assess the flood damage, don thick shoes, gloves and remove scattered debris. Toss any unwanted chaff the flood delivered: glass, nails, metal objects or other debris. Your goal is to give the grass the best chance to revive.


This is also your opportunity to see where the weak spots are in your drainage system and correct them. If only a few square feet of your property have standing water, figure out why. Where there is mild ponding, toss shredded mulch into any remaining damp areas to soak up excess moisture. If it’s deep in one spot, see if your house’s downspouts are guiding water toward it, or if you need to add fill to slope the property better.


Step 2: Remove soil and silt deposits

After you remove debris, uncover the grass. Scrape off any soil and silt deposited by the flood. Get a wheelbarrow and take it away.


Step 3: Aerate

When soil deposits aren’t as thick, wait until you see new growth appearing and go over the entire lawn three or four times with a core aerator. Benefits of aerating the soil include:

  • Improves the structure of the soil.

  • Improves the levels of oxygen in the soil.

  • Assists in breaking up soil layering caused by the soil deposits.

After doing the aerating, apply fertilizer for lawns, following package directions on amounts. You can then level any tilled and bare areas with a regular lawn rake or power rake.


Step 4: Re-seed? Re-sod? Or start over?

The next step in helping your lawn recover from a flood is sitting back and watching its growth for several weeks to determine the amount of damage incurred. After several weeks, you’ll be able to decide whether you’ll need a new lawn or you can repair various areas by reseeding or applying new sod. Here's where you may need an expert like Rooted in Nature to assess.


There’s no doubt about it, floods are messy and destructive and having to clean up the mess and possibly redo your entire lawn and landscape is nobody’s idea of fun. However, with a bit of hard work and soil preparation, you should be able to run barefoot through your newly recovered lawn before you know it. If your lawn has flooded and you're not sure where to start, remember you can count on Rooted in Nature of Maryland, contact us at 443-846-0199 or info@rootedinnaturemd.com.

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