With warm weather and sunshine finally looking like a reality for Vermont, many of us will be jotting down our lawn and garden to-do lists. As the grass greens up, lawn work often hits the top of the list. As you make your plans, don’t forget that Vermont passed a law in 2012 which prohibits the application of phosphorus-containing fertilizers to lawns in most cases. The use of nitrogen-containing fertilizers is also regulated. Specifically, the VT Agency of Agriculture notes the following:
- Fertilizer applied to lawns must contain no phosphorus (P) unless the lawn is newly established or testing shows P is low
- Nitrogen (N) content must be less than 15% slow release
- Fertilizer may not be applied to any impervious surface
- Fertilizer cannot be used before April 1 or after October 15
- Fertilizer may not be applied within 25 feet of the waters of the state.
Fertilization of lawns and gardens which already have enough N and P in the soil allows the excess to run off into waterways and make its way to our lakes and rivers. Once there, that extra fertilizer promotes excessive plant, algae, and cyanobacteria growth. Limiting the use of fertilizers to soils that really need them goes a long way to help improve water quality across Vermont.
You can have a beautiful lawn and keep extra P out of the environment by
- Taking a soil test first. That way you’ll know exactly what is needed and apply the right amount.
- Fertilize only with P-free and N-limited products. Most lawns in the Northeast have more than enough P already.
- Water sparingly. As long as you’re receiving about an inch a week, your lawn will be fine.
- Set your mower blade higher. Maintain a height of 3 – 4 inches and leave clippings on the lawn. They add organic material, P and N as they decompose. (Please do sweep up the clippings from pavement to keep those things out of the water.)
Keep the green in your lawn, not your lake!