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  • Staff Photo by Grant Morris

    The organic fertilizer that Tom Kelly sells is seen here pouring slowly from a pint glass. It's dark brown in color.
  • Staff Photo by Grant Morris

    The system that Kelly is selling is six installments and is applied to the lawn from early spring through around Thanksgiving.
Thursday, April 22, 2010

Organic lawn care hot topic

How do you know that people are interested is ecologically friendly lawn care? Check Margaret Hagen’s calendar.

“I didn’t even have a talk about organic lawns until 2008. Now I go out and deliver that talk several times each spring,” said Hagen, an educator with the UNH Cooperative Extension.

There are good environmental reasons to focus on the grass around people’s homes.

By acreage, grass is one of the nation’s four biggest crops, along with corn, wheat and soybeans. Those grassy areas, including golf courses, parks, cemeteries and ballfields as well as yards receive an estimated 70 million tons of fertilizer and 70 million pounds of pesticides, averaging roughly 10 times the amount of pesticide per acre as used on food crops.

Aside from the ancillary damage done to insect and wildlife, too much of this material ends up in waterways, where it can cause algae blooms, fish die-off and other bad events.

So it makes sense to change lawn-care habits to do less damage to the environment. However, in a world where the goal is to produce a green carpet in the minimum of time, that can be easier said than done.

“People have to be willing to take the time. Any time you’re trying to grow something and not use our traditional fertilizers and/or weed killers, you have to actually understand the biology of what you’re doing, and that’s more time- consuming,” said Hagen.

Consider phosphorus and nitrogen.

“Most organic turf fertilizer have 8 percent or less nitrogen in them,” said Hagen. To reach recommended nitrogen levels involves using “three to four times as much organic fertilizer” as chemical fertizlier.

However, most organic fertilizers contain phosphorus and potassium and most soil in New Hampshire has plenty of phosphorus already. As a result, Hagen said, using extra organic fertilizer to meet nitrogen markers can produce phosphorus run-off into adjacent waterways – just the sort of thing that organic lawn care tries to avoid.

Another issue is that organic fertilizers, in particular, tend to release their nutrients more slowly than chemical ones. Speedier release of nutrients, leading to a quick “greening” of your grass, is one of the main selling points of artificial fertilizers.

“My biggest piece of advice to people is do it slowly,” she said. “If you go from conventional commercial lawn care and switch immediately over to organic, your lawn is going to decline.”

That decline will occur because the nutrients from the synthetic fertilizer will have been used up before the natural nutrients begin to appear.

“Conventional is released in six weeks or less, and some organics take up to a year to release, you’ve got nothing going in the middle,” she said.

As a result, for at least a year, she said, people should use fertilizers that have a mix of both types to wean their lawns off the quick-hit nutrients.

Despite such concerns, Hagen says the benefits for the environment can be large, and over time it can benefit your lawn.

“Promoting the health of the soil – that’s the basic premise of organic lawn care or organic gardening of any kind. If you have good biological diversity, turf grows well,” she said.

Even if people don’t want to go organic, she added, they can reduce their environmental impact by shrinking the area planted with grass, which requires mowing – lawn mowers usually produce far more pollution per hour of operation than cars or trucks – and the use of fertilizer or pesticide.

Other quick steps, she said, are to fertilize in the spring and fall but not in the summer, to use a mulching mower that leaves clippings on the lawn so that their contained nutrients aren’t removed, and to make sure that you use only what your lawn needs.

“Instead of mindlessly buying that four-step program, check – does you lawn have crabgrass? Do you need to buy that combined (fertilizer and weed killer)?” she said. “Don’t buy combined use products unless you need them.”

Still, Hagen admits that the field can be intimidating.

“You go into the store and there are 20 different brands of fertilizer, and you throw your hands up and say what the heck,” she said.

David Brooks can be reached at 594-5831 or dbrooks@nashuatelegraph.com.