Dogs, Herbicides, and Weeds, Oh My!

The weeds, the dandelions─yuck.  Should I spray an herbicide?  But what about my dogs?  How can I do this safely?   So I usually put it off until the weeds get the better of me and I just have to spray them and try to keep my dogs off of the lawn for a day, or at least try.  Most herbicides state, ‘safe’ for pets after it has dried. But are they? Here is what my research uncovered:

  • Increased risk of bladder cancer.
    • Certain breeds have a higher risk for bladder cancer. These include West Highland white terriers, Scottish terriers, Shetland sheepdogs, beagles and wire hair fox terriers.
  • Routes of exposure include ingestion , inhalation, and transdermal exposure
    • Ingestion can include licking their paws, not just eating the chemical directly or munching on grass.
  • Pets can transfer the chemicals to people, since they track them inside the house on their paws. So the floors, carpets, furniture, and your clothing could also contain small amounts of herbicide.
  • Some herbicides are detectable for at least 48 hours after application, and sometimes longer. Those tested included 2,4-D, MCPP, and dicamba.
    • The chemicals can stay on the lawn a longer time if the weeds are brown, dying back, or if too much chemical is used.
  • Wind conditions are important when spraying chemicals. A neighbor may spray their lawn and some of the chemical will drift into your yard.

What can we do?  Well there are two paths.  One, is to learn how to use chemicals safely, and the other is to use something toxic to the weeds, but not to our pets.  A third path is to mow tall weeds, but that doesn’t control weeds in the lawn.


Buffy rolling around on the grass.
Buffy rolling around on the grass.
  • Spray the back yard one week and the front yard another time to allow a safe area for your dog.
  • Wash your dog’s paws after using the treated area, even if the chemical is dry, or applied a few days ago.
    • My rule of thumb is to treat the lawn as contaminated until a good rainfall washes it into the soil and the grass is dry. Only then allow them free reign of the yard.
  • Roundup can still cause vomiting, although considered safe once the chemical has dried.
  • Store chemicals away from where pets can reach them, and in heavy duty containers.


Unlike some of the herbicides listed above, which kill broad leaf plants and do not harm the grass, many of the materials listed below are non-selective and can kill grass along with weeds.  So do spot treatments.

  • Corn gluten meal is a natural herbicide. Corn gluten meal is more costly than corn meal, but corn meal also seems to reduce weeds. It acts as a pre-emergent herbicide that prevents seeds from germinating.  It does not kill mature plants.
  • Boiling water applied directly to the target plants.
    • If planting a new bed, try using boiling water to kill all the weeds, then mix corn meal into the soil to prevent weed seeds from germinating. This works well if you’re installing plant plugs and not using seeds.
  • Hand pulling. We do this for dandelions and creeping Charlie, and although initially it’s a big investment in time, in future years the amount decreases substantially.
  • Try citrus oil, cinnamon bark and clove oil applied directly to the weeds.
  • Use soil barriers to prevent weeds from growing. I’ve tried this around shrubs, and it works well.
  • Salt, but do not use a lot on flower beds or vegetable gardens since the salt stays in the soil and can be toxic for the desirable plants. Make a salt solution and spray it on driveway and patio cracks.
  • Vinegar draws the water out of the leaves, killing the leaves, but it may not kill the roots. Don’t use a concentration higher than a 5% solution.
    • A solution of vinegar and salt is also effective to kill weeds.
  • You can mix this with equal parts of chili pepper to deter animals.  Pour the solid sugar on the weeds.

I have not tried all of these techniques,  and I was surprised at the variety of methods.  Personally I use hand pulling as much as possible, and herbicide only with weeds that are too numerous and small to pull.

The main thing is to think about your pets and to plan your methods accordingly.  When I do succumb to using an herbicide, I try to apply it late in the day and about two days before a rain event.  For herbicides to be effective, the weeds have to be actively growing, so they need some sunlight before rain washes the chemicals off the plant.

If you suspect your pet has ingested a herbicide, contact your veterinarian, emergency vet, or a poison control center.

For more information check out these websites:

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