What are bare spots?

Recently, I have been asked to look at several lawns to help diagnosis their problems. 

As the weather has finally warmed up and lawns are transitioning from winter to spring, many lawns have bare spots in them. Bare patches are areas of your lawn that have exposed dirt and no grass.  

What causes Bare Spots in my lawn? If you notice Bare Spots in your otherwise lush, green and healthy lawn, they could be the result of excessive foot traffic, poor soil conditions, pet urine, grub infestation, chemical spills, fungal disease, buried rocks, or a variety of other things.

Several approaches exist to effectively patch these Bare Spots, however, it’s important to understand and address the underlying cause, so that this same problem doesn’t continue to manifest in your lawn.  

The first step in solving this problem would be to take a soil sample to see if the problem may be related to poor soil condition. 

This will also help you with determining if and how much fertilizer is required. 

Also, as our local soils have high pH levels and are high in salts, one of the major causes of bare spots could be salt damage. Salt damage occurs when salt accumulates in the soil to damaging levels. 

This can happen in different ways: either the lawn does not receive enough water from rainfall or irrigation to wash the salts from the soil or the drainage is so poor that water does not pass through the soil.

In these cases, salts that were dissolved in the water accumulate near the surface of the soil. In some cases, a white or dark brown crust of salts forms on the soil surface.

Salts can originate in the soil, in irrigation water, or in applied fertilizers. Salt damage can also occur if excess salts are applied, as from overfertilizing or contaminating the soil with deicing salts. 

In cold-winter areas, deicing salts can be splashed or washed from roadways and sidewalks onto lawns. Damage occurs the following spring, as the grass along the road turns yellow and dies. 

The only way to eliminate salt problems is to wash the salts through the soil with water. If the damage is only at a low spot in the lawn, fill in the spot. Improve drainage by aerating or amend the soil. If the soil drains well, increase the amount of water applied at each watering by 50% or more, so that excess water will leach salts below the root zone of the grass.

For sodium-based deicing salts, apply powdered gypsum to the soil and water thoroughly several times to wash out the sodium. 

Will grass spread to Bare Spots? It really depends on what grass type you have. You may be in luck if your lawn is comprised of either Kentucky Bluegrass, Bermuda Grass, Zoysia Grass, St. Augustine Grass or Creeping Red Fescue. 

These grasses have runners, or vine-like stolons above ground and stem-like rhizomes below ground, allowing them to expand sideways and gradually fill in any Bare Spots that may have taken residence in your lawn.  

How to fix Bare Spots in my lawn? Once you have identified and resolved the cause of the Bare Spots, it’s time to repair the damage. 

Typically, you would only seed in the late Summer, during the months of August or September, as seeds germinate in the Fall so as to sprout in the Spring. In the case of Bare Patches however, it is recommended that you seed the area right away, rather than leave it exposed.  

What to do if your Bare Spot is exposed soil: 

1. If you only see dirt and no additional layers of dead grass, your job is pretty easy. First, use a garden rake, shovel or other tool to loosen the soil around the Bare Patch several inches below the surface. 

2. Next, spread the seed at the recommended rate, lightly working it into the soil. For added benefits, cover the spot with some compost and work it all in together. 

Covering the spot with compost, newspaper mulch or straw will help keep the area moist and promote better germination of the seed. 

What to do if your Bare Spot has thatch or dead grass overtop: 

1. If you have any heavy thatch, or dead grass on top of the soil, you will need to loosen up these additional layers to expose the real dirt.  

2. Once you do this, you want to seed into, or spread a light layer of real topsoil, not Peat Moss.  

3. Spread the seed on the fresh topsoil or freshly prepared ground and lightly work it into the top 1/4 inch of soil, making sure everything is integrated.  

4. After you’ve planted your grass seed, the top inch of soil should be kept consistently moist but not soggy. 

This means misting it with water once a day, usually in the morning and again at midday, if needed. If the weather is hot and dry, you will need to mist with water more frequently.

If your grass seed dries out after it has started to sprout, it will die. Once the grass seed starts to germinate, continue to keep the top two inches of soil moist until the new grass reaches mowing height (normally between 2 1/2 and 3 1/2 inches). 

After you’ve mowed at least once, begin to cut back on watering to about twice per week and soak the soil more deeply (about 6 to 8 inches) each time to encourage the grass roots to grow down deep in the soil. 

Sources: 

• Ortho Problem Solver, https://www.ortho.com/en-us/problems-and-solutions/salt-damage-lawns 

• Good Nature Organic Lawn Care, https://www.whygoodnature.com/