According to a recent survey, it’s likely that you and your neighbors believe having a lawn that is safe for the environment is very important.¹ However, some common lawn care practices can contribute to water quality issues. Excess nutrients—especially nitrogen and phosphorus from fertilizers—that wash off our properties into local waterbodies can trigger algal blooms that cloud the water and deplete oxygen.
Many of us enjoy the time we spend caring for our lawns and are willing to try new practices as long as the results still look good.¹ Below are some simple strategies for creating and maintaining a healthy, attractive lawn that is also better for the environment.
Simple Recommendations for Every Lawn
Choose the Right Grass Seed
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Limit lawn areas to spots where grass will grow easily and will be used for outdoor activities.
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Select grass varieties that require less maintenance. For northern New England, look for seed mixes with higher percentages of turf-type tall fescues, compact-type fall fescues, and/or fine fescues.
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Opt for lower percentages of Kentucky bluegrass and/or perennial ryegrass.
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In shaded areas, choose shade-tolerant grasses such as fine-leaf or tall fescues.
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Including up to 10% white clover in your seed mix can help naturally fix nitrogen in the soil. Avoid clover if anyone in your household is allergic to bee stings.
Don’t Overwater
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If irrigating, 1 inch of water per week is typically sufficient.
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Overwatering can cause runoff and leaching of contaminants into groundwater.
Test Your Soil
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For soil testing instructions, visit: extension.unh.edu/resource/best-practices-submitting-your-soil-sample.
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Adjusting soil pH or organic matter content may be all that’s needed to improve lawn health.
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If your soil test results are acceptable but your lawn is still struggling, investigate other issues such as pests.
Mow Smart
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Mow grass to a height of 3 inches or more.
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Never cut more than one-third of the blade at a time to promote deep root growth.
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Leave clippings on the lawn as a source of slow-release nutrients.
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Never dispose of clippings in drainage areas, storm drains, wetlands, or water bodies.
For additional resources, visit: www.rochesternh.gov/stormwater-center
Recommendations for Lawns That Need Fertilizer
Determine How Much to Apply
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Measure the area to be fertilized to determine how much product you actually need.
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Only use the amount required. Nearly half of homeowners mistakenly apply the entire bag regardless of need.¹
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Store opened bags in airtight containers or share excess with others.
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Lawns older than 10 years generally require less nitrogen—especially if clippings are left on the lawn. Start with half the amount recommended on the bag and only increase if turf color and density do not improve.
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Apply fertilizer no more than four times per season, even at reduced rates, to stay within water-friendly guidelines.²
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Lawns less than 10 years old may need the full recommended amount but should still receive fewer than four applications per year.
Know When and Where to Apply
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Avoid fertilizing in mid-summer when grass growth naturally slows, or before heavy rain, when nutrients are likely to wash away.
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In northern New England, apply fertilizer no earlier than spring green-up and no later than mid-September.
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Follow local and state regulations. For example, in New Hampshire, fertilizers must not be applied within 25 feet of water bodies.
Choose the Right Fertilizer
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Avoid combination products that contain both fertilizer and pesticides unless both are truly needed.
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Select fertilizers with low or no phosphorus unless your soil test indicates otherwise.
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Fertilizer labels display a formula such as 20-0-15, indicating the percentages of nitrogen (N), phosphorus (P), and potassium (K).
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Look for slow-release formulations (greater than 50% water-insoluble nitrogen or WIN).
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Quick-release products should only be used when rapid turf growth is necessary, such as during new seeding to prevent erosion.
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Organic fertilizers are usually slow-release and contain beneficial micronutrients. They are also not petroleum-based, unlike most synthetic fertilizers.
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Regardless of the type, overapplying fertilizer or overwatering after application can cause serious water quality problems.
For more information, visit:
https://extension.unh.edu/resource/best-practices-submitting-your-soil-sample
¹ Survey Source:
Eisenhauer, B.W., & Gagnon, B. (2008). Changing Homeowner’s Lawn Care Behavior to Reduce Nutrient Losses in New England’s Urbanizing Watersheds: Report of Findings from Social Science Research. USDA CSREES Project #2006-51130-03656.
² Fertilizer Guidelines Adapted From:
Guillard, K. (Ed.). (2008). New England Regional Nitrogen and Phosphorus Fertilizer and Associated Management Practice Recommendations for Lawns Based on Water Quality Considerations. Turfgrass Nutrient Management Bulletin B-0100. College of Agriculture and Natural Resources, University of Connecticut. USDA CSREES Project #2006-51130-03656.
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