Grass Smells Like Manure Under Paddling Pool | How To Avoid

Has this ever happened to you? One minute you’re enjoying a lazy, sunny afternoon in your yard, with the kids playing happily in your portable pool. The next minute you catch an extremely unpleasant odor and you realize the grass smells like manure under your paddling pool.

Gross, right? But you don’t want to stop the kids’ pool time fun. So what do you do? And why does it smell so bad? Did you put the pool on top of your dog’s favorite go-to place? Unlikely! It’s usually just a natural function of grass.

Reasons Why Grass Under A Pool Smells So Bad

When grass is starved of oxygen and light it begins to rot and decay, causing it to start smelling like manure. It’s no different to your compost heap. Anything that goes into a compost bin (grass, raked leaves, weeds, etc.) is placed in the dark where it becomes really wet, heavy, warm, and SMELLY! This is because everything inside is dying and starting to decay. 

Grass under your pool will rot when exposed to the following:

  • Too much moisture
  • Too much nitrogen
  • Not enough oxygen
  • Not enough sunlight

It can get especially smelly if there’s mold in the grass too. The mold will get trapped under the pool, right in a dark, warm place where it can thrive.

Grass Smells Like Manure Under Paddling Pool
Decomposing Lawn

How Long Before A Lawn Starts Rotting

When your grass can’t get sun and oxygen even for 24 hours, it will become “dormant”. Dormant grass won’t grow, but it shouldn’t rot either. You can generally bring a dormant patch back to its full strength by leaving it open to the air, watering it thoroughly, and generally giving it a lot of help and attention.

If the grass underneath your portable pool remains cut off from sunlight and air for more than two weeks, then it will begin to die. Dead grass will naturally decay, and after two weeks the lawn will start to rot.

Getting Rid of Smelly Grass After Removing a Portable Pool

There are two ways to salvage your lawn after you’ve put the pool away:

  1. Dig up the affected area
  2. Rake and rehabilitate 


Dig up and discard the affected patch of lawn and either sow grass or put down new sod. Alternatively, turn the site into a flower bed or a new patio.

Throw the damaged grass onto your compost heap so it’s away from your lawn and can’t stink it up anymore.

Raking and Rehabilitating

Use a garden rake to scrape up most of the dead grass, then throw it onto your compost heap. You can then rehabilitate the area using the same methods I’ve suggested for digging.

Lingering Odors

If the odor still lingers, use baking soda to get rid of the smell. Mix one teaspoon of baking soda with one quart of water to make a solution. Pour this solution into a spray bottle and spray the dead grass patch in your yard. 

Baking soda is very safe to use on your lawn. It can also help to prevent mold growth. Just be sure to keep your dog off that area so they don’t try to get rid of the scent the only way they know how. 

How Long Does Decomposing Grass Smell For

Unfortunately, decomposing grass will smell until it’s done decomposing. Like any decaying life form, this could take weeks or months. The best way to remove the smell is to remove the grass entirely and reseed or re-sod over the top. 

How to Revive Grass After Removing Pool

If your pool has been in the same spot for the duration of the summer, chances are you won’t be able to bring the grass underneath back to life. However, if it has only been there for a short time, you may be able to revive the site so it’s good as new for the following season.

I recommend that you follow these steps if your grass needs reviving after you have removed a portable pool from the site:

  1. Till 
  2. Plant
  3. Water
  4. Weed
  5. Mow 
  6. Fertilize 
  7. Avoid


Using a shovel, trowel, or garden hoe to break up the soil. You’re essentially a According to Oregon State University, aerating the area will let the oxygen back in, and also break up the roots of the dead grass to let newer shoots in.

Sowing Seeds

Be plentiful! Spread your grass seeds! The more, the better, because you don’t want this patch of lawn to grow up…patchy and there is always a chance that some of the seed will be eaten by birds. 


Water the area right down to the first few inches of soil. This might seem like overkill, but it isn’t. Your dead lawn patch desperately needs water, nutrients, air, and sunlight. Don’t be afraid to let it have them. Repeat the process of watering regularly and adequately for the best results.


Don’t let weeds take root in your new grass. They’ll take over like ruthless dictators, and before you know it, there won’t be any grass left. 


Start mowing once a root structure has become established. Then, continue to mow as you normally would throughout the growing season. This will help stimulate the growth of the new shoots.


Rehabilitating your lawn needs good quality lawn fertilizer. I always use a lawn starter that contains a combination of both slow and quick-release nutrients and also has a high percentage ratio of nitrogen and phosphorous.

This ensures that the feed gets to work immediately but also continues to release nutrients as the new grass develops and also encourages the development of healthy blades of grass and strong root development.

Avoid the Area

Keep off this patch at all costs until the grass is firm and healthy. That means no dog activity, no kids running over it, no turning it into a mud hole, and definitely no covering it with your portable pool for the foreseeable.  

Preventing Your Lawn from Rotting Under A Pool

There are three main ways to prevent your lawn from rotting if it has been covered by a pool:

  • Use sand under the pool to improve airflow
  • Move your pool
  • Keep it off your lawn

Sand or Tarps

If you sprinkle sand on the grass under your pool, it will soak up all the bad smells you get from the rot. Your lawn might still receive damage, but it won’t smell nearly as bad.

Placing a tarp or similar under your pool can help save your grass. It can prevent excess moisture from getting trapped underneath, leading to mold. It can also help create air pockets that will keep your grass alive for longer. 

Move the Pool

If you’re able, routinely move your pool to a different spot on your lawn. This will allow for sun and oxygen to reach all the grass to prevent it from dying.

Keep the Pool off the Lawn

Moving your pool onto a patio or a deck will help you avoid the manure smell entirely, saving your lawn from decaying. 

Verdict: Grass Smells Like Manure Under Paddling Pool

Decomposing grass can leave a blemish on your lawn and a stench in the air. It’ll start decaying after two weeks if it can’t reach air or sunlight.

So, if you’re wondering why the grass under your portable pool smells so awful, then you should know that it’s a natural occurrence and somewhat unavoidable if you intend to keep it in one spot while the weather is fine.

The good news is there are things you can do to prevent your grass from rotting and steps you can take to get your yard looking good as new too.

In the long term, it’s worth thinking more strategically about where you place your pool. After all, you neither want to disappoint the kids nor put up with that awful manure smell from returning.