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Paul Wagner in Sagaponack. DANA SHAW
A lush green lawn doesn’t have to be chemically dependent and irrigation intensive.
That’s one of the sustainability messages that will be shared on Saturday, August 9, in Bridgehampton as the Sustainable Southampton Green Advisory Committee brings together a local builder, an organic lawn care provider and a water quality nonprofit leader to share how homeowners can change their maintenance practices in order to safeguard water and air quality as well as human health. The program is designed to highlight how living well can be done in harmony with the environment and how lifestyle choices have a ripple effect on the East End’s bays and watersheds.
Suffolk County Legislator Ann Welker will moderate the discussion, which will begin at 10 a.m. at the Hampton Library and include a Q&A with the audience. Local builder John Barrows will speak on sustainable construction strategies and home upgrades, Mecox Bay Conservancy Executive Director Jay Schneiderman will talk about improving local water quality, and Paul Wagner of tree, shrub and lawn care company Greener Pastures Organics in Southampton will share organic alternatives to chemical fertilizers and pesticides as well as smart irrigation techniques.
Wagner holds a degree in ornamental horticulture and is an International Society of Arboriculture-certified master arborist plus a state-certified nursery professional. He’s also the president of commercial soil-testing laboratory Soil Foodweb New York, which provides details of the range and quantity of microbes present in soil to determine the best steps to take to keep plants healthy.
“In an old growth forest, there might be 40,000 different species of microbes present,” Wagner said during a recent interview. “In a landscape, there might be 3,000 different species. It’s the microbes that are actually keeping the plants healthy in that natural ecosystem.”
He explained that microbes cycle nutrients in soil. When an organic fertilizer is applied to a lawn, the nutrients are not immediately absorbable by plant roots. First, bacteria, fungi and protozoa in the soil consume the fertilizer, and the nutrients become part of their biomass. Predatory microbes then come along and eat the original microbes, eventually releasing nutrients in plant-available form.
Organic fertilizer is slow-release, feeding plants over time. On the other hand, chemical fertilizer is water soluble and doesn’t stick around in soil. When chemical fertilizer is applied, excess nutrients that plants can’t take up quickly will leach into groundwater or wash away as stormwater runoff, ending up in surface waters and leading to algal blooms that threaten marine life and human health.
“If you put down a pound of nitrogen in the chemical form, maybe the plant picks up half the pound and the rest of it can leach,” Wagner said. “Whereas if you went with a half a pound of organic, it’s kind of like feeding a system, and it just basically stays there until the plant uses it.”
Wagner noted that Suffolk County has a turf fertilizer ban between November 1 and April 1.
“The potential for fertilizer runoff into surface water and leaching into groundwater is greatest during this time, as the grass is not actively growing and unable to absorb the nutrients,” the county’s “Healthy Lawns, Clean Water” Fertilizer Reduction Program notes.
New York State law prohibits the use of lawn fertilizer that contains phosphorus unless establishing a new lawn or a soil test shows that an existing lawn does not have enough phosphorus.
“This is not unique to Long Island,” Wagner said. “Chesapeake Bay is highly polluted with phosphorus and nitrates, and they have all the same restrictions. And you’ll find this in any environmentally sensitive area. They’ve adopted these restrictions.”
Wagner said he has some clients whose lawns are organic by default: They don’t apply anything — chemical or organic — to their lawns, and they let nature take its course.
Other clients refrain from using pesticides for the sake of their family’s health and to reduce their landscape’s negative impacts on wildlife, but they still want a green lawn. They choose organic fertilizers and biostimulants such as sea kelp, humic acid and compost tea.
“We still use fertilizer,” Wagner said. “We just gear it toward growing the right sorts of microbes.”
The second pillar of a sustainable lawn is smart irrigation.
“Everything for us is trying to mimic Mother Nature. Nowhere in nature does it rain 15 minutes a day at 6 o’clock in the morning,” Wagner said.
Watering every day results in roots that stay near the soil surface, where all the water is, he said. The roots will not have a reason to grow down deeper into the soil to reach moisture. And because the roots stay shallow, they can’t access all the nutrients that are deeper down.
Smart irrigation starts with understanding the soil type. In sandy soil, an inch of water can penetrate the soil 12 inches quickly, while in clay soil, it may only penetrate 3 inches. “It doesn’t percolate quite as well,” he said.
With sandy soil, he recommends watering every other day. With clay soil, twice a week will do.
“You try to mimic rainfall,” he said, explaining that the idea is to give the plants plenty of water, let the soil drain and dry, then apply more water.
“Deeper and infrequent irrigation to mimic rainfall — that’s a very good and smart use of water,” he said.
Determining how much water to apply each week also depends on the type of grass. He said tall fescue needs an inch of water a week in summer, while bluegrass requires an inch to two inches a week.
Wagner recommends a tuna can test: leave cans at various areas around the lawn, put the irrigation system on for 10 minutes, and measure the depth of water applied. Extrapolate from there how many minutes the system should run in a week to deliver adequate water but not too much.
He pointed out that dry soil heats up faster than wet soil, so delaying the start of irrigation in spring can discourage crabgrass, which germinates once the soil temperature reaches 55 degrees.
“A lot of times we tell people, just leave the system off until June, until we start really needing [water], till Mother Nature turns the rain off. And then, if it’s raining three days a week, you don’t need to irrigate. It’s raining two days a week — depends on how much — maybe we would add one day a week of irrigation. Once we’re down to one day a week, maybe you would add two days a week of irrigation. And then once you get into a drought situation, then you’re probably more like three days a week of irrigation.”
The panel discussion and Q&A will take place on Saturday, August 9, at 10 a.m. at the Hampton Library, 2478 Main Street, Bridgehampton. Admission is free.
