Spring Tips for a Watershed-Friendly Yard

Spring has just arrived, which means thousands of Pennsylvanians will soon stroll outside to work in their yards. Individually, most residential lawns in PA are less than ½ acre, but in total cover nearly 1.5 million acres.¹ Because they cover such a vast area, lawns have an enormous impact on the environment, including our surface and groundwater resources. Some neglected lawns have the potential to produce large amounts of stormwater runoff, which can harm local water quality.  Minimizing runoff from lawns and surrounding landscapes is the goal of these spring season yard care tips.

Cleanup
Collect and properly dispose of any stray trash winter winds may have left behind. Mulch or compost fallen leaves and garden cuttings you missed in the fall so they don’t wash away during a spring or summer rainstorm into a stream or lake where they can lower oxygen levels.

Patch Grass
Inspect for bare spots in your lawn and landscape beds, especially if they are located on a hillside. A thick lawn should produce less runoff than a thin lawn with exposed soil. Reseed grass in mid-spring, when the threat of hard frost is past but it's still too early for most weeds to grow. Consider adding a layer of mulch to bare planting beds or planting them permanently with native meadow plants or another groundcover before summer heat arrives.  

Test Soil
Collect a soil sample from your lawn and have it tested so you know what kind of fertilizer is best, and how much you will need.  Over fertilizing won’t improve grass growth, may pollute local waterways including groundwater, and is also wasted money. Soil test kits, with instructions, are available from some commercial lawn care firms, garden centers, and every county Penn State Extension office.

Fertilize Carefully
Nitrogen is commonly the most important nutrient for good grass growth.  Unfortunately, it's not easy to measure with a soil test. Instead, careful experimentation is the best way to determine how much nitrogen your lawn needs. For many established lawns, applying about 2 pounds of Nitrogen per 1000 square feet of lawn, per growing season, is a starting rate that balances typical grass needs against water pollution risks from overfertilizing. If your grass grows well at this level, try reducing the application rate next year.

Look for slow-release nitrogen fertilizer products because this form of nitrogen is less likely to harm water quality.  Several small fertilizer applications spread over the growing season are better than one single application, and the Pennsylvania Fertilizer Law limits total nitrogen applications to 0.9 pounds per 1000 square feet of lawn per application.  Penn State Extension suggests applying your lawn's annual nitrogen fertilizer needs in thirds: 1/3 in mid to late spring, 1/3 in late summer, and 1/3 in late fall.²

The Pennsylvania Fertilizer Law

Revision to Pennsylvania's Fertilizer lawn in 2022 means lawn care companies and DIY homeowners are now required to follow nutrient application rate limits, fertilizer application location restrictions, and best management practices specified on both the fertilizer label and in the law. The following limits have been set for fertilizer application on turfgrass (lawns):

• 0.7 lbs./1,000 ft.² of plant available nitrogen per application
• 0.9 lbs./1,000 ft.
• NO phosphate may be applied unless:
   - A soil test indicates a phosphorus need
   - You are establishing, reestablishing, or repairing a turf area
   - You are using an enhanced efficiency phosphorus fertilizer
   - Application of enhanced efficiency phosphorus, natural organic fertilizer, or organic-based fertilizers may not exceed 0.25 lbs./1,000 ft² (0.5 lbs./1,000 ft ² per year maximum).

Fertilizer limits are set per application, so it is important to test your soil to determine your lawn's actual nutrient requirements and guide you on the number of applications needed each year.

To further minimize pollution risk, applicators must follow site, rate, and timing restrictions:

Apply fertilizers to the right place:

• Do not apply near waters, storm drains, or drainage ditches
• Maintain a 15-ft. buffer from waterways
• Fertilizer that lands on an impervious surface (like roads, sidewalks, driveways) must be swept back onto turf
• Apply only to intended application site

Apply fertilizers at the right rate:

• Apply product using a properly calibrated fertilizer spreader

Apply fertilizers at the right time:

• Do not apply if ground is snow-covered or frozen
• Do not apply if heavy rain is expected
• See PDA factsheet on fertilizing

Mulch Clippings
Grass clippings are a free source of nitrogen fertilizer, so let them decompose – or grasscycle -- on your lawn.

Mow Sharp and High
A sharp mower blade cuts grass cleanly which improves turf health and promotes denser growth. Setting the mower deck high, 2 ½ inches or more, helps lawn grass shade out weeds and survive dry spells, reducing the need for weed control and irrigation. 

Sweep Away Clippings and Fertilizer
Use a leaf blower or a broom to push stray grass clippings and fertilizer granules off sidewalks and driveways onto your lawn so they don’t wash into storm sewers or ditches that drain into your local stream.

Plant Trees and Shrubs
Spring's a good time to plant native trees and shrubs which provide important water quality benefits. They reduce stormwater by intercepting rainfall, increase infiltration by penetrating the soil, and filter pollutants through the rich leaf litter that gradually develops beneath the canopy. If you plant them along the edges of your lawn, they also reduce the total area you need to mow!

Aerate Turf
Grass does best, and traps more stormwater, when it grows in loose soils.  Surprisingly, many home lawn soils are just the opposite. They're often compacted from years of heavy use including outdoor parties, riding mowers, small tractors, and even parked cars. If your grass struggles despite proper fertilization and watering, compaction may be the problem. Core aeration is a process that removes finger-sized soil plugs from the top layer of a lawn so air and water can penetrate better to support root growth. Most yard care companies offer core aeration as a service and many garden centers rent the equipment for ambitious DIY's.

Go Big
Is this your year to install a major water quality practice on your yard?  Possibilities include replacing turf with native meadow plants; protecting a stream or drainage swale with native trees and shrubs; capturing the discharge from your downspouts in a raingarden, or rain barrel; or redirecting any downspouts that currently spill onto sidewalks or a driveway into your lawn or planting beds so the stormwater soaks into the ground instead of running off. Finishing these projects in the spring means you get to watch them provide water quality benefits before winter returns.

1. Penn State College of Agriculture, Department of Plant Science, Home Lawns
2. Turfgrass Fertilization: A Basic Guide for Professional Turfgrass Managers, Penn State Extension