How to get rid of dog poop smell in your yard
The smell is rarely coming from what you can see. Here is where it is actually coming from, and what works on it.
If your yard smells and you have already picked up everything visible, the smell is not coming from what you picked up. It is coming from what soaked in.
Where the smell actually lives
Waste left on grass for more than a day or two stops being a surface problem. Rain and watering carry the residue down into the thatch layer and the top inch of soil, and that is where bacteria keep working on it. Removing the solid afterward removes the thing you can see and very little of the thing you can smell.
Urine does more of this than most people expect. A yard that smells persistently, particularly in a warm week after rain, is usually telling you about months of accumulated urine in a few favored spots rather than about any individual pile.
Heat and humidity make it worse because the bacteria are more active. St. Louis in July is close to ideal conditions for this, which is why the complaint is seasonal.
What works
Water, in quantity. The cheapest and most underrated treatment. Soaking the affected area dilutes what is in the soil and carries it deeper, below the layer where you smell it. A proper soak beats a light sprinkle by a wide margin, and a sprinkler left running on one patch for twenty minutes does more than a hose passed over the whole yard.
Enzyme cleaners made for pet waste. These contain bacteria and enzymes that break down the organic compounds rather than covering them. They genuinely work, they need to be applied to a wet area and kept damp while they do their job, and they need reapplying. Buy one made for outdoor use rather than a carpet product.
Aerating a compacted area. If the same corner has been used for years, the soil there is compacted and will not drain. Water and enzyme treatments cannot reach what they need to reach. Punching holes in it first makes everything else work better.
What does not work
Lime gets recommended constantly. It raises soil pH, which can reduce odor temporarily, and it will also damage your grass if you apply enough of it to matter. The yards we have seen treated this way have brown patches and still smell.
Baking soda has the same problem on a smaller scale, with less effect.
Scented sprays and granules cover the smell for a day. The underlying material is still there and still working.
Bleach should not go anywhere near a yard a dog uses.
The part nobody wants to hear
Every treatment above is remediation. You are cleaning up a problem that has already happened, and the yard will be back where it started in a few months unless something changes about how long waste sits there.
A yard cleared weekly does not develop this problem, because nothing is in contact with the soil long enough to soak in. A yard cleared once a season develops it every season, no matter what you spray afterward.
If you have been treating the smell every summer, the treatment is not the thing to change.
A note on timing
If you are dealing with this after a long gap, do the clearing first and the treatment second, and give it a week between them. Treating a yard that still has material in it accomplishes very little, and the enzyme product you just paid for goes to work on the wrong thing.
