Crossville Chronicle, Crossville, TN


March 25, 2013

Plateau Gardening: Choosing the right weed killer

CROSSVILLE — Successful weed control hinges on choosing the right alternative for the particular plants you wish to eliminate and for conditions when and where the herbicide is to be applied.

Tennessee’s lingering cold, snow flurries, rainy and cloudy weather have stalled the typical growth spurt we expect by spring’s onset (March 20). Certain herbicides work best when plants are growing vigorously and temperatures are at least 60 degrees Fahrenheit but not over 85 degrees F. They may be less effective this year than if late-winter weather had been warmer and drier. Be sure to read the product label.

Note for gardeners who use household vinegar (5 percent acetic acid with 95 percent water) as an organic weed control and don’t have an herbicide label: Vinegar works by drying out plant tissues. Online advice suggests temps should be above 60 degrees F and that the weeds should be growing in sunlight. If conditions are not right, vinegar may not be effective.   

Know the weed types you are dealing with and their life cycles. It helps pinpoint the time of year and during which life cycle stage that nuisance variety is most vulnerable. Landscape weeds can be divided into three types: broadleaf, grasses and sedges.

Within each category weeds have one of three basic life cycles: summer annual (heat-loving, the seed-to-plant-to-seed life span lasts 12 months or less, germinates in springtime), winter annual (cold-tolerant, the seed-to-plant-to-seed lifespan lasts 12 months or less spanning 2 calendar years, germinates in late summer or in autumn) or perennial (roots and sometimes the entire plant is winter hardy, these plants persist more than two years).

There are a number of herbicide options to consider. "Post-emergence" weed control agents are applied to plant parts above ground. Some post-emergence herbicides kill top growth on contact (contact herbicides). Others (systemic herbicides) move into and within the plant to affect below ground and interior plant parts and processes. Post-emergence herbicides are most effective when used to attack unwanted plants that are little, young and not stressed by heat or cold. The objective is to get rid of weeds before they mature and produce seeds or other persistent reproductive structures. Weeds typically produce lots of seeds. Those seeds can survive most post-emergence control methods lethal to growing plants.

"Pre-emergence" herbicides affect germinating seeds. They are spread on the soil. Dry granule forms are typically activated by watering afterwards. Pre-emergence controls should be in place two or three weeks before conditions are right for seeds of the targeted species to sprout. Springtime pre-emergence herbicides are often used against crabgrass. Yellow forsythia bushes in bloom signal soil temperatures are right for grass seed germination. Corn gluten meal is an organic "weed and feed" pre-emergence product that may be used to treat crabgrass, creeping bentgrass, smart weed, dandelions, purslane, lambs quarter, barnyard grass and Bermuda grass in cool season lawns. Corn gluten keeps sprouting seeds from forming normal roots. Treated seedlings die from dehydration when soil gets dry.

Some herbicides are "non-specific" or "nonselective." They kill all vegetation they contact (desirable and undesirable, broadleaf or grass). "Specific" or "selective" herbicides target certain plant species or particular plant categories (broadleaf or grass). However, while broadleaf-specific herbicides containing 2, 4-D and dicamba won’t hurt established turf they may kill tender, young grass seedlings. Always read label directions before purchasing. When mixing and applying, follow directions precisely.

• • •

Plateau Gardening is written by Master Gardeners for gardeners in Tennessee’s Upper Cumberland Region.  Contact UT Extension Cumberland County at P.O. Box 483, Crossville, TN 38557 (484-6743) for answers to horticulture questions, free publications and how to become a Master Gardener. Send email comments or yard and garden inquiries to Master Gardener Rae,

Text Only
  • Melling, Sounds of the Country¬†at Hebbertsburg Community Center

    Jack Melling and Sounds of the Country will entertain at the Hebbertsburg Community Center on Saturday, May 3, from 5:30 to 8:30 p.m.

    April 22, 2014

  • Marriage licenses (Published April 23, 2014)

    April 22, 2014

  • Pleasant Hill Ramblings CSA.jpg Pleasant Hill Ramblings: CSAs are a win-win situation

    Every Wednesday after 1 p.m. from May through October, there is a steady stream of people converging on the kitchen of Heritage Hall on Church St. in Pleasant Hill with baskets and bags. Inside the kitchen there is excited chatter as they discuss the array of vegetables, some varieties never tried before. Farmer Dave Myers and his helpers provide this largesse of vitamins to the members of the CSA.

    April 21, 2014 1 Photo

  • plateau gardening.jpg How to collect and submit soil sample

    Garry, a new resident in Crossville, emailed to ask how to gather a soil sample and where to take it to have testing done. Your local University of Tennessee Extension office is the place to go. Those in the Crossville area should call UT Extension Cumberland County at 484-6743. A staff person at the office can explain how to collect soil samples. (Those new in town who may not know where the Extension office is located may also call for driving directions.)

    April 21, 2014 1 Photo

  • 5-2 white cane days.jpg Lions Club White Cane Days returns May 2 & 3

    The Fairfield Glade and Crossville Lions Club members will hold their annual White Cane Days fundraiser Friday, May 2, and Saturday, May 3, at several locations. This is a major fundraiser throughout the state of Tennessee and many parts of the world to help assist blind, sight impaired and deaf individuals. This is an event that only happens once a year.

    April 21, 2014 1 Photo

  • 20140412_110402.jpg Kids get creative at Youth Expo

    Cumberland Artisans for Creative Expression (CACE) held its annual Youth Expo Saturday, providing young people an opportunity to try their hand at a variety of artistic endeavors, from music and writing to painting and traditional crafts of weaving and spinning.

    April 17, 2014 4 Photos

  • AROUND THE TOWN: The Easter egg hunt that never was

    The Easter Bunny should be able to deliver his baskets in pretty nice weather this weekend. The Good Friday and Easter holiday weekend should feature much warmer temperatures than we had earlier this week when snow showers fell on Cumberland County. Cumberland County students were released Tuesday for spring break, but their last day of school for the week found snow and ice falling from the sky and temperatures in the 20s. Students will return to class on Monday.

    April 17, 2014

  • 127 Seniors.jpg Jay Fox performs for seniors after receiving new prosthesis

    On Friday, April 11, the members of the 127 Senior Center had another good time playing bingo and dominos. Bingo was called by Arlene Simmons and Helen Lord, and the bingo gifts were provided by Bob Folger of State Farm Insurance.

    April 15, 2014 1 Photo

  • Marriage licenses

    Publised April 16, 2014.

    April 15, 2014

  • pleasant hill ramblings.jpg PLEASANT HILL RAMBLINGS: Pancake breakfast held for cancer research

    During the year various groups connected with the Pleasant Hill Elementary School provide a Saturday morning pancake breakfast to support the Relay for Life campaign.

    April 14, 2014 1 Photo