Hort Q&A: How to repair a lawn

Carla Smith, horticulture educator
Pottawatomie County Extension Service

I had a client call last week who was removing a swimming pool and was wanting to fix her ‘blank lawn spot.’  What can be done for patch repair of a lawn?

The weight and shade of a pool can compact the soil and will shade out the existing grass. Many of us may have experienced this with a summer ‘simple-set’ pool or kiddie pool at some point.  The type of sanitation for the pool, either chlorine or salt can also affect the soil.  Chlorine will generally dissipate in sunlight and heat rather quickly. Shock treatments and a range of chemicals used can play a role in the health of the soil later.  After a few rains, many of those issues will correct, unless severe.  When the pool is drained, it is best to let those chemical levels lower a bit before pouring that into your lawn area.  (If you have a pool and have forgotten to add chlorine on the proper schedule, you’ll understand how quickly that can change in sunny weather.)

Once the pool is removed, sunlight will be a big help in resolving the lawn problems.  If the lawn was healthy Bermuda before, and the pool was in place for one summer, pieces of Bermuda will begin to regrow from the roots in many cases.  The fishy or dank smell is decomposing plant material.  Again, with sunlight and rainfall, that will naturally correct in time.  If the pool is removed in August or early September, there will be more time for some recovery of the grass before winter.  Note that late established Bermuda can be at a greater risk for winter kill the first year. 

The edge of the Bermuda will begin to creep back into the blank circle. Using a garden fork to lightly loosen the soil can help aerate the area and encourage the roots to send up new shoots.  This does not require full turn over or rototilling.  ‘Fluffing’ the blank space will allow air back into the soil as well as helping rainwater to not pond on the blank lawn space.  After working the soil, if it is still lower than grade, you may need to add some additional topsoil.  If sand was used under the pool as many pool kits recommend, you may need to re-level or spread that out to smooth the mowing surface of the lawn.  Plugging the area with small plugs taken from a full and healthy area of your lawn will also help the space to fill in faster. 

When a pool has been in place for a longer period of time or if the pool is removed later in the fall (October or later), more renovations will be needed.  Larger areas may also require more time.  As a quick fix for the fall/winter, you may want to seed with annual ryegrass to fill in the lawn when it cools off.  Bermuda can then be re-established in the late spring the following year.  Seeding Bermuda is not recommended after July, so waiting until warm soil temperatures in late spring will have much better results.  Next week, we will discuss more on cool season lawn establishment, regardless of the size of the area.  For general lawn management tips, see our OSU Lawn Management Fact Sheet: https://extension.okstate.edu/fact-sheets/lawn-management-in-oklahoma.html

Oklahoma State University, as an equal opportunity employer, complies with all applicable federal and state laws regarding non-discrimination and affirmative action.  Oklahoma State University is committed to a policy of equal opportunity for all individuals and does not discriminate based on race, religion, age, sex, color, national origin, marital status, sexual orientation, gender identity/expression, disability, or veteran status with regard to employment, educational programs and activities, and/or admissions. For more information, visit https:///eeo.okstate.edu