Feb. 18 2010 12:00 AM

While much of the country is still digging out from under mountains of snow, it’s hard to imagine that spring is just around the corner. Believe it or not, warmer temperatures will be with us quite soon, and with them will also begin the emergence of plush lawns and, unfortunately, some nasty weeds as well.

Benjamin Franklin once said, “An ounce of prevention is worth a pound of cure,” although I’m sure the famous statesman wasn’t talking about his landscape. When it comes to weeds, using an ounce of prevention before they take root will be worth a great deal more than a pound to cure an uncontrolled infestation.

What is a weed?

Simply put, weeds are plants that grow in the wrong place. However, left to their own devices, they can become much more than just an inconvenience. Once a weed infestation takes control of a lawn, it acts like a cancer. Weeds steal vital water, light and nutrients from healthy plants. They not only mar the visual beauty of the landscape, but they can create an unhealthy and potentially life-threatening environment for people with severe allergies.

You may recall, back in late July or early August while working on your client’s property, you suddenly spotted an unsightly clump of crabgrass. You took immediate action to try to eradicate the problem before it had a chance to spread, and made a note to be sure to take care of it the following spring. The “following spring” is here and the time to act is now before other weeds are able to rear their ugly heads.

While you’re never going to be able to completely eradicate weeds from a property, the goal is to control and limit infestations to a small number. This can be accomplished by wiping out as many weed seeds as possible b e f o r e t h e sprouts have a chance to see the light of day. One of the ways to accomplish this is with the use of a pre-emergent herbicide.

As the name suggests, pre-emergent herbicides must be applied before weeds have time to emerge. In order to be effective, a pre-emergent herbicide should be applied as early as February in the warmer climates to no later than mid to end of April for the cooler areas.

Pre-emergent herbicides prevent the germinating weeds from establishing in the lawns by inhibiting cell division in the young root system. This results in the death of the young seedling weed shortly after germination, so they are unable to grow.

Herbicides can be applied by spraying with liquid, or in granular form. They can also be mixed with fertilizer. After application, the area should be saturated to create an effective weed prevention zone.

The way most pre-emergent herbicides work is that when they are applied to the ground and watered in, they create a blanket over the soil. This “blanket” forms a barrier just below the surface. As the weed seed germinates and begins to grow, it hits this barrier. The weed cannot penetrate the barrier and, therefore, cannot grow upward to the surface to pick up air so, it eventually dies.

When the weed plant dies prematurely, it does not produce its seed. Over a period of time, by applying these herbicides, eventually you can gain control and give your clients a lawn virtually free of these noxious weeds.

A word of caution: once a pre-emergent herbicide is applied, do not aerate the area. If you do, all you are doing is punching holes in this barrier or blanket. The crabgrass or Johnsongrass will find its way through the holes in the blanket, causing the herbicide to become ineffective.

Although the majority of chemical herbicides are perfectly safe when applied properly, there are still some negative preconceptions about using chemicals that may cause concern with some of your clients. With eco-friendly trends gaining in popularity, the market for biological herbicides and organic weed control products is growing.

“In terms of business, there are a certain percentage of people out there who are wary about putting any chemicals near their homes or children,” says Nate Elfner, owner of Elfner Landscape and Organic Lawncare, Delaware, Ohio. “Corn gluten meal (CGM) is a popular all-natural substitute for pre-emergent herbicides.”

CGM is a by-product of commercial corn milling that contains the protein fraction of the corn. One of the problems with corn gluten meal is that rain and other soil activity can reduce its effectiveness. You can control how much you water right after the application, but you can’t control rainfall.

Sometimes weed seed that has been prevented from germinating can wait until CGM is washed away and grow right through the bare spots.

Organic mulch works quite well as a cost-friendly biological alternative to chemical herbicides. A twoto three-inch layer should be all that’s needed to keep the weeds from sprouting. Another organic alternative which works quite well is compost. This can be incorporated into the soil, improving the health of desirable plants and giving them more leverage to edge out weeds.

Effective irrigation also plays an important role in weed control. Good water distribution will increase the thickness of the turf, creating a continuous sward to protect against weeds. Drip irrigation systems can be designed as an effective weapon to use on the war on weeds. Since water is only being delivered at the roots of desired plants, weed seeds only a few inches away may not be able to get the water they need in order to germinate. The more you are able to control the placement of water in a landscape, the better able you will be to control and prevent weeds from getting at it.

Core aeration is another viable way to establish a healthy turf and strengthen its resistance to weeds. Aeration loosens compacted soil and increases the availability of water and nutrients to the turf. The tine of the aerator will also sever roots, rhizomes, and stolons of the grass, stimulating the grass plants to produce new roots and shoots to fill in the holes. This can help create a much denser turf, which will increase weed resistance. If the turf is healthy and strong, it will help crowd out the weaker weeds.

Another low-herbicidal alternative in the battle against the weed is Integrated Pest Management (IPM). This process uses a combination of cultural, mechanical, biological and, if necessary, limited amounts of chemicals. Early planning plays a major role in IPM.

Site preparation, plant selection, plant health and quality are all important elements of the process. Weeds are completely eliminated on a new site before planting to reduce problems in the first year and thereafter. When possible, landscape contractors select plants that thrive in an area with little intervention, so they will have the best chance to compete with weeds. New plants are carefully inspected before being planted to make sure they are not bringing weed, or weed seeds along with them.

Whatever process you believe to be best, you should always keep in mind your client’s preference and needs. Some people may not care what products or methods you use as long as they don’t see something strange sticking out from their manicured lawns. Others may be very involved with environmental issues, and will insist that you manually pull up any intrusive weed as an alternative to using chemical herbicides.

Yet, even with the most diligent care, it is pretty much impossible to completely eliminate weeds from your client’s property. The best you can hope for is the ability to manage and control them so your client’s landscape can appear virtually weed-free.

In order to be totally effective, a weed control program must be accompanied by a good turf management program. Proper fertilization, irrigation and mowing greatly reduce and often eliminate significant grass weed problems before they begin.

Ben Franklin would be proud.