With spring right around the corner, many of us are starting to think about gardening and lawn care. As a sustainability educator with 17 years of experience, I want to share a simple but impactful change that benefits the environment, your pets, and your wallet: stop using chemical pesticides and fertilizers on your lawn.

My passion for this issue grew stronger after researching clinical studies that have found troubling links between lawn care chemicals and canine cancers. One study states: "Chemicals were commonly detected in grass residues from treated lawns, and from untreated lawns suggesting chemical drift from nearby treated areas. Thus dogs could be exposed to chemicals through contact with their own lawn (treated or contaminated through drift) or through contact with other grassy areas if they travel..."*

Another study found pesticides in the urine of dogs - linking those chemicals to an increased risk of canine bladder cancer. If these chemicals are affecting our pets, it’s hard to believe they’re benign for us humans, especially our children playing on the grass.

Even if your lawn care company says they’re only fertilizing your lawn, it’s worth rethinking. When it rains, the runoff from fertilized yards carries those nitrogen-rich chemicals into streams, ponds, and lakes, causing harm to wildlife and ecosystems.

When I see a monoculture lawn (the blades of grass all the same type) I get the opposite reaction than the homeowner probably intended. This signals a toxic environment and the presence of harmful chemicals.

Let’s refocus our energy away from chemical based lawn care practices. You’ll save money, your grass will still grow, and you’ll make a difference to the living beings around you. I’ve never used pesticides or fertilizers, and my lawn thrives just fine. You can stop all chemical applications and all will be fine. If stopping all the work on your lawn seems too drastic (I promise it will all be okay), the URI Master Gardener hotline is a resource for information about natural lawn and garden care, and their advice is free! You can email them photos and questions at gardener@uri.edu.

Let’s Talk Fertilizer:

After talking to my colleague Angie Langevin, Conservation Biologist & Permaculture Design Expert, these are her words of advice if you want to maintain a healthy lawn while protecting the environment:

The best approach is to avoid fertilizer altogether. Even organic fertilizers introduce excess nitrogen and phosphorus into the ecosystem, which often washes into streams and pollutes waterways. Instead of relying on fertilizers, consider these practices first:

Set the mower blades to 3 to 4 inches (or ask your lawn service to do so). Taller grass develops deeper roots, making it more drought-resistant and reducing the need for watering. It improves soil structure and microbial activity, reducing dependency on fertilizers.
- CLOVER’S BENEFITS:
  - Clover is a nitrogen-fixing plant, meaning it takes nitrogen from the air and converts it into a plant-available form (nitrate and ammonium). Plants can’t use nitrogen directly from the air; they need it in an ionized form, which clover can provide. Clover grows well alongside fescue grass and won’t overtake it. When you mow a lawn with both clover and fescue, the clover clippings act as a natural fertilizer due to their high nitrogen content.
Using Compost:
- Compost helps when reseeding areas with bald patches (e.g., damaged by snow plows or pet urine).
- Apply compost under the seed to improve germination rates.
- Don’t use compost on existing, healthy grass, but compost tea can be sprayed on the lawn for extra nutrients.
No-Mow May – Let your lawn grow naturally until June to give it a strong, healthy start. This helps grass establish deeper roots and promotes lush growth.
Embrace Plant Diversity – Instead of a single type of grass, allow beneficial plants like violets, self-heal, and plantain to grow. They improve soil health and create a more resilient lawn.
Fertilizer as a Last Resort – If you must fertilize, opt for a well-balanced organic fertilizer with equal nitrogen, phosphorus, and potassium (NPK). Fox Farm offers a good option - “Happy Frog Premium Lawn Organic Fertilizer”

*Sources:

1. Household chemical exposures and the risk of canine malignant lymphoma, a model for human non-Hodgkin's lymphoma: https://pubmed.ncbi.nlm.nih.gov/22222006/#:~:text=Results:%20After%20adjustment%20for%20age%2C%20weight%2C%20and,CML%20(odds%20ratio(OR)=1.7;%2095%%20confidence%20interval%20(CI)=1.1%2D2.7).

2. Case-control study of canine malignant lymphoma: positive association with dog owner's use of 2,4-dichlorophenoxyacetic acid herbicides: https://pubmed.ncbi.nlm.nih.gov/1870148/#:~:text=Abstract,environment%20should%20receive%20further%20investigation.

3. Glutathione S‐transferase theta genotypes and environmental exposures in the risk of canine transitional cell carcinoma: https://pmc.ncbi.nlm.nih.gov/articles/PMC6524089/

4. Canine exposure to herbicide-treated lawns and urinary excretion of 2,4-dichlorophenoxyacetic acid: https://pubmed.ncbi.nlm.nih.gov/8019373/

5. Detection of herbicides in the urine of pet dogs following home lawn chemical application: https://www.sciencedirect.com/science/article/abs/pii/S0048969713003100