By: Betsy Washington 03-14
Homeowners in Virginia routinely apply millions of pounds of nitrogen and phosphorus fertilizer to their lawns even though most established lawns require no phosphorus in order to thrive. Scientists at VA Tech have estimated that lawn runoff from improper and unnecessary fertilization adds millions of pounds of nitrogen and phosphorus to Virginia’s watersheds each year. This nutrient overload causes excessive algal growth (sometimes toxic) which leads to oxygen depletion, most visibly seen as dead zones in the Chesapeake Bay. Dead zones, where very few plants and animals can live, are not restricted to the Bay but can occur in any body of water including our Lake. This is a growing problem because lawn and turf grasses are now the largest “crops” in the Chesapeake Watershed, and are increasing by nearly 9% each year. While algal blooms are natural phenomena, their extent, regularity and severity are greatly increased by nitrogen and especially phosphorus fertilizer runoff in all water bodies.
The growing amount of these nutrients running off into our Virginia watersheds, led the state to a new law that went into effect in January 2014. The law with wide bipartisan support prohibits the sale of lawn maintenance fertilizer containing phosphorus. Additionally, many water treatment plants spend large sums of money to remove phosphates so this law will help save everyone money – but the true benefactor will be our lakes and bay (Barcroft and Chesapeake).
Tips for a Healthy and Pollution Free Lawn:
Lawns do not necessarily need routine fertilizing, so before any lawn treatment this spring, have your soil tested. Test kits can be obtained at Green Springs and at public libraries for a small fee. The test results will give specific recommendations for your soil, and save you money and guesswork. Soil tests performed by WID in Lake Barcroft several years ago, showed that most Lake Barcroft properties did not need fertilizer and in fact, many had disturbingly high levels of phosphorus. Test results did show that many would benefit from applications of pelletized limestone to raise the soil pH to levels where plants could use nutrients already available in the soil.
You can avoid the expense of applying fertilizer and the hassle of worrying about runoff, by using a mulching mower and leaving your lawn clippings on your lawn each time you mow, and applying a half inch of compost or leaf mulch to your lawn a couple of times a year. This will improve your soil and increase populations of beneficial soil microorganisms that naturally recycle all the nutrients your plants need, delivering them right to their roots, while also protecting them from disease. These beneficial organisms are greatly reduced by synthetic fertilizers (and pesticides).
Mow high (at 2 – 3”) and keep your mower blade sharp. Never remove more than 1/3 of the grass blade at one time. This will help your lawn outcompete any weeds.
Water deeply and less often to promote vigorous root growth that helps your lawn resist drought.
Increase your wildlife habitat, and reduce the amount of lawn area, by planting native shrubs and groundcovers in large sweeping borders and around your trees. Your trees will thank you and these borders will provide a lovely, low maintenance “frame” around your lawn that will set it off to perfection and give it that professionally landscaped look. Once done, sit back and actually enjoy your garden and wildlife without all the sweat, tears, and pollution.
Finally, if a soil test indicates that you need fertilizer, here are a few tips to help green up your lawn, instead of the lake. Be sure your lawn company follows these guidelines.
- NEVER apply fertilizer when the ground is frozen or plants are dormant – plants can only absorb nutrients when they are actively growing. You will waste time and money and the fertilizer will simply run off into the lake. The best time to fertilize most lawns is in fall, not spring or summer.
- Do not allow fertilizer to fall on impervious surfaces like driveways or walks and avoid using fertilizer near the lake. Do not fertilize near storm drains or drainage swales before heavy rains.
- Do not allow your lawn company to use old fertilizer that contains phosphorus. It is unnecessary and will pollute the lake.
- Choose a fertilizer with SRN (Slow Release Nitrogen). This form of nitrogen breaks down gradually over time so that lawns can make better use of it over the growing season, and it helps prevent massive runoff into the lake.