Proper Centipede Lawn Care

Proper Centipede Lawn Care

Centipede Grass needs a low-nitrogen, fertilizer without phosphorus or potassium (9-0-0).  Fertilizing with a nitrogen percentage of more than 9 more than twice a year will harm Centipede turf and promote lawn disease, weeds, and insect infestation.  I use corn glutton meal (a fertilizer but also a pre-emergent broadleaf weed controller) in early spring and early fall.  There is no weed and feed product on the market that will do more good than harm to Centipede grass.  Centipede grass can be effectively greened up using lawn sulfur.  Sulfur lowers soil pH but Centipede’s ideal pH is Acidic (4.5 to 5.5) so there is little danger of lowering the pH too much.

Healthy Centipede grass requires more micronutrients than macronutrients (nitrogen, phosphorus and potassium).    Soil amendments should contain vitamins B-1, B-12, gibberellins, indoles, auxins as well as trace elements of boron, iron, zinc, cobalt, copper, manganese, molybdenum and sulfur.  These nutrients should be chelated, meaning they are instantly available to the grass. They should be salt and chlorine free to be safe for the plant and the soil.  The soil amendment I use is a liquid product containing cold-water kelp, humic acid, and molasses.   This contains 30+ natural trace elements and plant growth hormones.  This should be used instead of fertilizer during the spring and summer months for the best results.

The lawn should be aerated at least once a year.  I use a liquid aerator instead of mechanical methods.  I have found this to be faster and much more effective.  Mechanical means of aerating penetrate the ground only about 3 inches where the liquid penetrates 6-8 inches relieving compaction (especially in clay soils) and allowing roots to develop deeper in the soil for better drought survival.

Centipede lawns develop thatch quickly.  Again, I use a liquid dethatcher over mechanical means.  Liquid dethatchers contain bacteria and enzymes that quickly decompose thatch and all other dead organic matter returning their nutrients to the soil.  The end product of decomposing action is humus (nutrient rich top soil).  Rich soil has a humus layer of 6-8 inches with a carbon level of 12-14 percent.  The average lawn has a humus level of 3/8 to ½ inch with a carbon percentage of 2.  Liquid dethatchers quickly and naturally build humus.

Irrigation: Irrigate only when the grass shows signs of moisture stress, such as off color, wilting or rolling leaves. Then apply enough water to wet the soil to a depth of 4 to 8 inches. This generally requires about 1 inch of water, which should last 7 to 10 days. Early morning is the best time to irrigate, while evening irrigation is more efficient.  Too much or too little irrigation causes lawn diseases.

Mowing/Mulching puts back in your lawn nutrients both macro nutrients (N-P-K) and the necessary micro nutrients (vitamins B-1, B-12, gibberellins, indoles, auxins as well as trace elements of boron, iron, zinc, cobalt, copper, manganese, molybdenum and sulfur.)  All organic matter decomposes into humus (fertile topsoil) quickly when the biological dethatcher is applied.  Leaves should also be mulched into the lawn.  They have excellent humus building properties.

A healthy Centipede lawn is weed free, insect free, and an asset to the value of your home.

Centipede Grass Deficiency Symptoms:

Nitrogen – Nitrogen deficiency is rarely a problem with Centipede Grass.

Potassium – Most grasses use potassium to build cells and tissue.  Centipede grass however, is not like most grasses and handles potassium poorly.

Phosphorus – Potassium is harmful to the root systems of Centipede Grass.

Micronutrients and trace elements handle this job in Centipede grass.

Plants require smaller amounts of the secondary macronutrients-sulfur, calcium, and magnesium. Iron, manganese, zinc, copper, chlorine, boron, and molybdenum are still essential for growth but are required in even smaller amounts. They are often referred to as micronutrients or trace elements. Each of these macro- and micronutrients serves specific purposes for our grass.

Magnesium – Centipede foliage will appear yellowish green with red tinted edges.  Even though it’s classified as a secondary macronutrient, magnesium is still critical for growth. Without magnesium, plants can’t use light to make food through photosynthesis!  Plants also need magnesium to be able to take in their other essential nutrients and to make seeds.

Calcium – New leaves will be small and grass will be rust colored.  As with sulfur, Centipede grasses also need calcium to make proteins. Calcium promotes new root growth and facilitates overall plant vigor.

Sulfur – Fully-grown leaves turn yellow.  One of the secondary macronutrients, sulfur helps plants maintain their dark green color. Mainly, plants use sulfur to create essential proteins.  In Centipede grasses, sulfur is essential for nitrogen-fixing nodules, and necessary in the formation of chlorophyll. Plants use sulfur in the processes of producing proteins, amino acids, enzymes and vitamins. Sulfur also helps the plant’s resistance to disease, aids in growth, and in seed formation.

Iron – The new grass will turn yellow.  Iron makes for healthy, dark green growth. As with magnesium, iron is essential for photosynthesis.  Iron is necessary for chlorophyll formation, and without it, plants wouldn’t be able to carry out essential cellular functions.

Manganese – The new grass turns yellow.  In short, manganese makes things happen. Manganese is necessary for chlorophyll formation, and without it, grasses would not be able to carry out essential cellular functions.

Zinc – Grass leaves will appear shriveling, narrow bladed and smaller than usual.Plants use zinc in conjunction with other elements to carry out many natural processes including forming chlorophyll.

Boron – Yellowed grassing and immature growth.  Centipede grasses don’t need much of it, but boron does facilitate nutrient uptake and it helps plants to grow new tissue. 
Molybdenum – Fully grown and mature grass appears gray-green.  Grasses need molybdenum to produce essential proteins.

Copper – Copper contributes too many natural processes including plant metabolism and reproduction.

Centipede decline

In mature Centipedegrass lawns (3 or more years old) problem areas sometimes appear in the spring and grow worse throughout the summer. These problem areas usually develop in thatchy turf, compacted soils, drought areas or areas under other stresses. Since a specific disease organism has not been identified as the cause, the problem has been broadly named “Centipede decline” and is used to describe the most common problems observed on Centipedegrass. These include dollar spot, large patch, fairy rings, nematodes, ground pearls and nutritional problems.

Symptoms: the grass gradually deteriorates and is replaced by weeds or other invassive grasses. The grass often greens up in early spring, but gradually turns off color, wilts and dies. These areas resemble Centipedegrass suffering from drought conditions.

Examination of the turf in these areas reveals little root development. Many of the stolons, or runners, have no root attachment to the soil. Some small discolored roots may be found in the thatch, or the organic layer. The grass may be dead in the center of the discolored area with often dark green, leaves radiating into the healthy grass.
Dollar spot is a disease that is often seen on centipedegrass during the summer. The symptoms of this disease are light brown spots 2 to 4 inches in diameter. It does not appear to cause serious damage. Centipedegrass that is declining because of other factors may have more dollar spot than nearby healthy grass. The grass may continue to decline in the affected patches, especially in dry weather, for a long time after the disease activity has stopped.

Fairy rings:  Fairy ring symptoms are large circular dead spots, dead rings, or green rings (3 to 20 feet in diameter) that enlarge for several years. Mushrooms of the fungi that cause this disease may be present at the edge of the rings or throughout the circles sometime during the year. Mushrooms may not develop for several years and suddenly appear following a weather pattern that induces mushroom development. Effective treatments are not known for fairy rings in lawns, however, rototilling the soil and replanting healthy grass has eliminated the problem in some cases.  Note:  Mushrooms not in a circular pattern are not a sign of Fairy ring.  Mushrooms often develop over dead tree roots as part of the decomposition process.

Sting Nematodes have been associated with the decline in sandy soils in some cases. The sting nematode has been shown to cause very serious damage on Centipedegrass in sandy soils in the Carolinas. Centipedegrass affected by this nematode will become thin and even die during hot-dry weather. Incorporation of organic matter in the soil may help overcome nematode damage; however, care must be taken to avoid too much nitrogen being released for Centipedegrass.

Ground pearls are small scale insects that attack the roots of Centipedegrass and may cause circular dead areas that resemble fairy ring. The spots enlarge each year and only weeds grow in the spots. Ground pearls are identified by the presence of small pearl-like bodies on the roots or in the soil. The pink adult stage that crawls is present during early summer. A control is not known for the ground pearls. Other types of grass, such as Bermuda grass or Bahia grass, appear to be less sensitive to ground pearls and should be considered for lawns with severe ground pearl problems.

Nutritional factors, including low potassium levels in sandy soils, high phosphorus levels, the use of too much nitrogen fertilizer, and low or high soil pH (5.5 is best) have been associated with the problem. High soil pH will cause Centipedegrass to turn bright yellow, especially in the spring, due to iron deficiency (iron chlorosis). High phosphorus levels can increase iron chlorosis since it can replace iron in the plant. The use of fertilizers high in phosphorus may contribute to the decline of Centipedegrass.  High nitrogen caused the stolons to be above the soil where they are more susceptible to damage by cold weather. More centipede decline usually occurs in the spring and summer following very cold winters or following winters with unusually warm weather and then late cold periods. Excess nitrogen reduces cold and drought tolerance of Centipedegrass.   Potassium may help to reduce stress during the summer and winter.

Centipedegrass is not very drought tolerant and is damaged during very dry weather. Irrigation when needed will help reduce damage from drought stress. Localized dry spots of soil that are hydrophobic (difficult to wet) have been associated with declining patches of Centipedegrass. The soil in these patches needs extra aeration.  
The use of chemical/synthetic herbicides (as sprays or in fertilizers) has been associated with the decline problem.  Once a good stand of Centipedegrass is established, weeds usually are not a problem because of the allelopathic activities that Centipedegrass has against other plants. Therefore, herbicides should not be needed on Centipede grass if it is managed properly.

Centipedegrass is not very shade-tolerant and does not grow well under trees with dense foliage. Root competition from nearby trees may increase drought stress and sometimes causes fairy ring-like symptoms. The landscape should be redesigned to use mulch or shade-tolerant groundcover plants in these areas if the trees cannot be removed.

Centipedegrass will usually spread over dead areas more rapidly if the old grass is removed and the soil loosened (aerated). New sprigs or overseeding in the areas will facilitate faster recovery.

Control: Cultural practices provide the most effective means of preventing centipede decline.