Taking an environmentally sensitive approach to pest management


Missouri Environment & Garden



AUTHOR

Brad S. Fresenburg
University of Missouri
Division of Plant Sciences
(573) 884-8785
fresenburgb@missouri.edu

Understanding Over-the-Counter (OTC) Lawn Care Products

Brad S. Fresenburg
University of Missouri
(573) 884-8785
fresenburgb@missouri.edu

Published: March 1, 2010

Seed Products

Fall still remains the best time of the year to establish cool-season grasses such as tall fescue and Kentucky bluegrass. However, we tend to receive numerous calls every spring about planting grass seed. Therefore, homeowners need to understand several key points about purchasing the right type of seed and how to be assured they are doing so.

Seed tags: All grass seed bags have a seed label printed or pasted on the bag. Several pieces of information on the label should be considered before seed is purchased. A seed tag will list the species (Kentucky bluegrass, tall fescue, perennial ryegrass, etc.), variety name (Kenblue, Abbey, Plantation, Crossfire II, Shining Star, etc.), purity (should be greater than 90 percent), germination (should be greater than 80 percent), weed seed content (percent) and noxious weed seed content (percent) and testing date (should be 12 months or less). The species and variety name of the seed will tell you exactly what you’re buying. As long as the purity and germination are acceptable, the next most important information to consider is the weed listings. The best products list 0 percent for weeds and noxious weeds. Any product containing weed seed will list the type of weed seed contaminating the turfgrass seed. Avoid any seed product containing noxious weeds.

Specific blends and mixtures: The number of seed products being sold over-the-counter can be overwhelming to homeowners. However, by looking at the seed tags on products, several can be eliminated immediately. These include products that contain large percentages of ryegrasses. Many of these seed products are packaged for national sales and while they are excellent products for many areas of the country, they are not the best for the type of climates we deal with in Missouri. Concentrate more on the products that are tall fescue blends or mixtures of tall fescue and Kentucky bluegrass. By doing this the selection choices become more narrow and simplified.

Individual varieties (from different venders) of tall fescues can be found locally to create your own blends. Measure equal portions of each variety used and combine thoroughly in a large clean bucket or trashcan. You have now created your own all fescue blend. The same can be done to develop your own mixture. Combine a blend of tall fescues with a blend of Kentucky bluegrass in the correct portions and you just created your own mixture.

Blends (3 to 4 varieties in equal portions) of turf-type tall fescues can give deep emerald green appearances with a slightly coarser texture than the bluegrasses. They tend to be a deeper rooting plant, therefore requiring less water than a bluegrass lawn. They are not as susceptible to dollar spot and summer patch, but generally will require some fungicides for the control of brown patch disease. Several varieties of turf-type tall fescues offer superior resistance to brown patch and therefore will improve turf quality. Tall fescues will tiller to help with recovery, but tend to be clumpy with severe thinning. They also grow well in full sun to partial shade.

Mixtures, such as turf-type tall fescues (in a blend) with Kentucky bluegrasses (90 percent fescue, 10 percent bluegrass), combine the advantages or strengths of each species to mask the weaknesses of the other. Any grass seed mixture with perennial ryegrass should not exceed 20 percent perennial ryegrass, as it is susceptible to most of the diseases list above. Ryegrass is not very heat or drought tolerant and does not recover from thinning of cover. Unfortunately, many seed mixtures and blends available to homeowners at local garden centers contain large amounts of ryegrass (both annual and perennial) and fine-leaf fescues (creeping red fescues, hard fescues, etc.). Fine-leaf fescues have little tolerance for direct sunlight.

Fertilizers

Fertilizer products vary as much as any other type of home lawn care product. Just as we discussed seed tags on the seed products, homeowners need to learn what they can about fertilizer products by looking at the guaranteed analysis usually listed on the back panel. Fertilizers, usually contain nitrogen (N)-phosphorus (P)-potassium (K) as a percentage (ei. 28- 3-3) of the net weight, are specified in this section called the “guaranteed analysis”. Many fertilizers are generally in a quick release form. Fertilizers of this type are immediately available to the plant giving a quick flush of growth that last only a few weeks before tapering off. Turfgrasses prefer a more even feeding throughout the growing season rather than the peaks and valleys typically seen in their growth rates with quick release fertilizers.

Fertilizers that contain slow release forms of nitrogen sources will be listed in the analysis. Nitrogen derived from polymer-coated urea (PCU), sulfur-coated urea (SCU), or methylene-ureas indicates to you that a portion of this product is slow release. The guaranteed analysis will state this information. Fertilizer products containing at least 30% slow released nitrogen to as much as 100% are desirable. One can simply determine that percentage of slow released nitrogen in a product by taking the percentage of nitrogen derived from slow released sources and dividing by the total percentage of nitrogen in the product. Example: If a product has 28% nitrogen (28-3-3) and the guaranteed analysis specifies that 10% of the nitrogen is derived from methylene-urea, then take 10 divided by 28 to equal a 35% slow release fertilizer.

Be sure to apply fertilizer products according to the application instructions on the label. Over applications of many synthetic OTC fertilizers can cause lawn injury.

Natural organic fertilizers become an excellent choice for home lawns since they are classified as 100% slow release. They typically have lower percentages of nitrogen, requiring more product per unit area, providing better distribution of material for a more uniform application. Organic fertilizers have no potential for lawn injury and can be applied at any time of the year. Keep in mind that organic fertilizers require soil microbes to break them down, therefore warm soil temperatures are necessary to favor soil microbial activity.

Granular Pest Control Products

Granular pest control products (crabgrass preventers without fertilizer, broadleaf weed controls without fertilizer, fungicides for disease control, and insecticides) are available to homeowners through a variety of brand names for controlling weeds, diseases and insects. As with any pest control situation, it is important for homeowners and gardeners to first identify the pest. Then ask, “Why is the pest there?” So often, we are in a hurry to get something applied to control the pest that we often forget to think about what we may do differently in our lawn care practices to favor the grass and not the pest. Following good cultural practices (tall mowing height, maintain high density, good fertility program, good watering practices) will often provide a lawn that will compete well with weeds, diseases and insects.

When the need for such a product is justified, it is important to apply only what is needed – never more than what is specified on the label. All of these products will specify how many square feet (5,000, 7,500, etc.) the net contents of the bag will cover. Even distribution of the product is important to the effectiveness of the product. It is also important to note any special instructions with these products, such as; applying granules to wet leaf surfaces (from morning dew) or to be sure to water in with ½ inch of water. With all granular materials, it is also important to sweep sidewalks and driveways. Keep the product where it is needed and not in our drains, sewers and ground water.

Combination Products

Combination products are those that most homeowners are familiar with. These are products that combine a fertilizer with a pest control material. Crabgrass preventers and Weed n Feeds are the most common.

Crabgrass preventers: These are products, most often with a fertilizer, that are designed to control many summer annual grasses (crabgrass, goosegrass, foxtails, etc.) and broadleaf weeds (knotweed, spurge, purslane, etc.). Timing and proper watering are keys to their success. Crabgrass preventers are preemergence materials that need to be applied prior to the germination of the weed seed. In Missouri, that can range from late March (southern) to mid- April (northern). Preemergent materials (Barricade, Dimension, Pre-M, Ronstar, etc.) also need to be watered in with at least ½ inch of water. This can be timed with a rainfall or irrigated in.

Keep in mind that good cultural practices (tall mowing height, good turf density, and proper fertility and watering) will provide a turf that competes (> 80% control) so well with annual weeds, that crabgrass preventers could be avoided.

Weed n Feeds: Weed n Feed products are often mistaken as crabgrass preventers or the term “Weed n Feed” is often misused. While the terminology could apply to crabgrass preventers, because they do keep weeds out of your lawn and feed it, most of these products are marketed for broadleaf weeds. Weed n Feed products contain active ingredients such as 2,4-D, MCPP, dicamba, triclopyr, etc. Crabgrass preventers contain active ingredients such as prodiamine, dithiopyr, pendimethalin, oxadiazon, etc. (Barricade, Dimension, Pre-M, Ronstar).

Several points need to be made about Weed n Feed products. While we do recognize broadleaf weeds (annuals and perennials) in the spring, majority of those well established broadleaves (dandelions, plantains, etc.) are perennials. Perennial broadleaf weeds are more easily controlled in the late summer (September). If significant weed pressure exists, then the application of a Weed n Feed product at that time will provide better control. If only a few broadleaf weeds exist, then spot treatments with an RTU would be a better management practice than a blanket application of a Weed n Feed.

The primary reason Weed n Feed products fail in their control, is the fact that the product was not applied when leaf tissue was wet from morning dew. Prills of the product provide better control when particles can adhere to the leaf blade of broadleaf weeds for a period of time. Weed n Feed labels do specify this in the application instructions of these products.

Another reason Weed n Feed products fail is the immediate watering in of the product. Unlike the crabgrass preventers, these do not get watered in immediately and often specify the avoidance of immediate rainfall in the forecast. They also specify not mowing 24 hours prior to and after application of the product.

Liquid Pest Control Products

Many liquid pest control products are also available to homeowners. These are more in the form of herbicides (Trimec, Weed-b-Gon, etc.), however, other products can be applied through a hose end applicator (most popular one being Ortho) for disease and insect control. Be sure to follow the instructions for the hose end applicator of your choice to set the correct rate of application.

Many liquid products are now being marketed in disposable hose end applicators. They do not require any mixing, calibrating or clean-up. The mixing and calibrating is done by the design of the applicator.

Several of the weed control products have spot treatment labels that require only a few teaspoons or tablespoons per gallon of water that can be applied through a pumpup sprayer. Problems that develop with this type of application, is over applying the solution. Do not drown the weed in spray mix. The proper application is to spray the weed to wet the leaf surface, and then stop.

Ready-To-Use (RTU) Products

These are the latest in over-the-counter products that makes life easy for many homeowners and gardeners. They provide ready-to-use solutions for spot spraying weeds or treating individual plants for a disease or insect problem. There are usually in a liquid form and marketed in a handy spray bottle that eliminates the need for mixing or calibrating sprayers and spreaders. Simply read the label and follow the instructions provided.

It can be intimidating to walk into a garden center and see shelf after shelf of lawn care products. One approach may be to search out a specific product on the web first. Another would simply be to take your time and decide which product will meet your needs and then what is the best means of applying that product. Do not forget your local extension office is only a phone call away, if questions arise.

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REVISED: October 23, 2012