Tag: Lawn

Crabgrass Preventers

Crabgrass preventers are another name for preemergence herbicides that prevent crabgrass seeds from developing into mature plants. Many people have a somewhat foggy idea of how they work and assume they kill the weed seed.  Such is not the case. They do not kill the seed or even keep the seed from germinating but rather kill the young plant after it germinates.  Therefore, they do not prevent germination but prevent emergence.

Crabgrass preventers are just that – preventers. With few exceptions they have no effect on existing crabgrass plants, so they must be applied before germination. Additionally, preventers do not last forever once applied to the soil.  Microorganisms and natural processes begin to gradually break them down soon after they are applied. If some products are applied too early, they may have lost much of their strength by the time they are needed. Most crabgrass preventers are fairly ineffective after about 60 days, but there is considerable variation among products.

For most of Kansas, crabgrass typically begins to germinate around May 1 or a little later. April 15 is normally a good target date for applying preventer because it gives active ingredients time to evenly disperse in the soil before crabgrass germination starts.  Even better, base timing on the bloom of ornamental plants. The Eastern Redbud tree is a good choice for this purpose. When the trees in your area approach full bloom, apply crabgrass preventer. A follow-up application will be needed about 8 weeks later unless you are using Dimension or Barricade. Products that do require a follow-up application include pendimethalin (Scotts Halts) and Team (Hi-Yield Crabgrass Control).

We recommend crabgrass preventers be applied before fertilizer so that the grass isn’t  encouraged to put on too much growth too early. However, it may be difficult to find products that contain preemergents without fertilizer. Those that don’t contain fertilizer are listed below.

Barricade – Howard Johnson Crabgrass Control Plus with 0.37 Prodiamine 00-00-07

Pendimethalin – Scotts Halts

Team (Benefin + Trifluralin) – Hi-Yield Crabgrass Control

Dimension – Hi-Yield Turf & Ornamental Weed and Grass Stopper

By: Cassie Homan

Dealing with Chiggers

Chiggers are mites, not insects. And like all mites, the adults have eight legs.  However, the larva only has six legs.

Though the bright red female adult is tiny (about 1/20th of an inch) the larva is much smaller (about 1/150th of an inch). Only the larvae are parasitic and attack animals. The larva injects digestive juices into the skin, which causes a rapid swelling. In the center of the swelling is a “feeding tube” from which the chigger sucks out liquefied skin cells. Feeding usually continues for 2 to 4 days.

Protection from chiggers uses two approaches. The use of a repellent can discourage chiggers from attacking. The most effective repellents are Deet and permethrin. Both chemicals are applied to your clothing. The second approach seeks to reduce chigger populations. Keeping the lawn mowed regularly can help, but large populations may require the use of an acaricide. Effective products include bifenthrin (Talstar, Hi-Yield Bug Blaster II, Hi-Yield Bug Blaster Bifenthrin, and Ortho Lawn Insect Killer Granules), cyfluthrin (Tempo 20, Bayer Vegetable & Garden Insect Spray) and carbaryl (Sevin).

For more information go to: https://www.bookstore.ksre.ksu.edu/pubs/MF2107.PDF

By: Cassie Homan

Have You Seen Slime Mold?

Slime molds are common on turf and mulch and sometimes on tree trunks. Slime molds are not fungi and are no longer classified as such. They belong to the Kingdom Protista rather than Kingdom Fungi. On turf, you might see large numbers of small gray, white or purple fruiting structures, called sporangia on leaf blades during cool and humid weather throughout spring, summer, and fall. Affected areas are often several inches to 1 foot in diameter. During wet weather, the fruiting structures may appear slimy. As the structures dry out in hot weather, they become ash gray and break up easily when touched.

Homeowners often are concerned that this is a disease organism that will kill the grass, but slime mold feeds on bacteria, other fungi, and dead organic matter. It simply uses the turf as a structure on which to grow. However, slime mold can damage turf by completely covering leaf blades and interfering with photosynthesis. Chemical control of slime molds is not necessary. Use a broom or a heavy spray of water to dislodge the mold.

Slime molds on mulch often attract attention because of their bright colors and disgusting appearance. Common names are often quite descriptive. For example, the “dog vomit” slime mold is a bright, whitish color that resembles its namesake. It eventually turns brown and then into a hard, white mass. Slime molds do not hurt anything, but most people do not find them attractive and want to get rid of them. Simply use a shovel to discard the offensive organism and then stir up the mulch for aeration.

By: Cassie Homan

Fall Lawn Care

The month of September signals the prime time to fertilize your tall fescue or Kentucky bluegrass lawns. If you could only fertilize your cool-season grasses once per year, this would be the best time to do it.

These grasses are entering their fall growth cycle as days shorten and temperatures moderate (especially at night). Cool-season grasses naturally thicken up in the fall by tillering (forming new shoots at the base of existing plants) and, for bluegrass, spreading by underground stems called rhizomes. Consequently, September is the most important time to fertilize these grasses.

Apply 1 to 1.5 pounds of actual nitrogen per 1,000 square feet. The settings recommended on lawn fertilizer bags usually result in about 1 pound of nitrogen per 1,000 square feet. We recommend a quick-release source of nitrogen at this time. Most fertilizers sold in garden centers and department stores contain either quick-release nitrogen or a mixture of quick- and slow-release. Usually only lawn fertilizers recommended for summer use contain slow-release nitrogen. Any of the others should be quick-release.

The second most important fertilization of cool-season grasses also occurs during the fall. A November fertilizer application will help the grass green up earlier next spring and provide the nutrients needed until summer. It also should be quick-release applied at the rate of 1-pound actual nitrogen per 1,000 square feet.

By: Cassie Homan

Is My Lawn Still Alive?

Normally, a healthy lawn can stay dormant for a good 5 weeks and still recover. After the five weeks are up, it is important to keep the crown hydrated because if the crown dies, the plant dies.

The recommendations differ for a lawn that was over watered or received so much rain this spring so that it produced a limited root system. Such a lawn may die unless allowed to slowly enter dormancy. This is done by shutting off the water gradually. For example, instead of watering several times a week, wait a week before irrigating. Then don’t water again for two weeks. Thereafter, water every two weeks as described below.

Cassie Homan
Horticulture Agent

Apply about 1/4 inch of water every two weeks to hydrate the crown. This will be enough to hydrate the crown but not enough to encourage weed germination and growth.

If you are wondering if the turf is still alive, pull up an individual plant and separate the leaves from the crown. The crown is the area between the leaves and the roots. If it is still hard and not papery and dry, the plant is still alive. When rains and cooler weather arrive, the turf should come out of dormancy. However, we will probably have to deal with weeds that germinate before the turfgrass grows enough to canopy over and provide enough shade to keep weed seeds from sprouting.

Use this ‘Lawn Problem Solver’ to find a solution for your home:
http://www.k-state.edu/turf/resources/lawn-problem-solver/index.html

By: Cassie Homan