HomeWHENWhen To Fertilize Zoysia Grass

When To Fertilize Zoysia Grass

Zoysiagrass is an important turfgrass used throughout the southern regions of the United States and into the transition zones where both cool-season and warm-season grasses are adapted.

The improved turf-type zoysiagrass will produce a dense, low growing turf that has a slow lateral growth but normal leaf growth. There are two types of leaf blade textures with zoysiagrass: fine and coarse-bladed. Because of its leaf blade stiffness, zoysiagrass can be difficult to mow, and the mower blade will need to be sharpened frequently throughout the growing season. See HGIC 1212, Zoysiagrass for additional information on care and varieties.

Producing a yearly maintenance calendar for managing turfgrass consistently year after year can be difficult in a state with such a diverse climate as South Carolina. Because of this, it will be important to monitor temperatures and apply the needed management practices based on that year’s climate. Important times to monitor the weather are late winter or early spring when the turf is coming out of dormancy and early fall when first frost are forecasted. Last frost dates and first frost dates can vary by several weeks to a month from the coastal areas of South Carolina to the foothills of the Upstate.

This turfgrass maintenance calendar may be used on turf growing throughout the state; however, management practices will need to be adjusted based on the year’s climate and the region where the turf is grown.

January through April

Mowing: Mow the lawn slightly lower than the regular summer mowing height of 1½ to 2 inches. The mower setting should be around 1 to 1½ inches high. Be careful not to set the mower too low, as it may scalp the lawn. This should be done just before the time of lawn green-up, which usually occurs during late April or early May. If possible, use a mower with a bagger to collect the clippings and remove any dead material left from winter dormancy. Alternatively, the lawn can be hand raked to remove the excessive dead leaf material from the lawn surface. Grass clippings decompose quickly and do not contribute to thatch.

A sharp mower blade will cleanly cut the grass blades as opposed to tearing the leaves. Dull mower blades rip rather than cut the grass blades. The resulting ragged ends on the blades make the grass more susceptible to diseases. Typically, sharpen the mower blade after every 15 thousand square feet of lawn mowed. If ragged ends of leaf blades become apparent after mowing, the blade needs sharpening.

The date of initial turf greenup can be quite variable. In the coastal and more Southern regions of South Carolina, this generally will occur sometime during April, but further inland, this may be as late as mid-May. It is not unusual for zoysiagrass to green up and be burnt back several times during the late winter or early spring due to late season frosts. Because of possible injury to the lawn and the potential fire hazard, do not burn off zoysiagrass to remove excessive debris. For more information on mowing, refer to HGIC 1205, Mowing Lawns.

Thatch Removal: If a thatch layer becomes a problem, use a dethatcher or vertical mower to remove it. Consider dethatching zoysiagrass when the thatch layer is greater than 1 inch. This turfgrass species normally produces a hefty thatch layer, so a little thicker thatch than for other turfgrass species is acceptable. For best results, use a dethatcher with a 2- or 3-inch blade spacing set a ¼-inch depth. Do not use a power rake with a 1-inch blade spacing, as severe turf injury may result. Use a lawn mower with a bag attached or hand rake to collect and properly dispose of the turf material pulled up. For more information on thatch removal, see HGIC 2360, Controlling Thatch in Lawns.

Aerification: Core aeration is the process of punching small holes in the turf and into the soil to alleviate compaction, thus allowing air to get to the root system. This will help to correct problems associated with poor infiltration and drainage. Once the threat for frost has passed, lawn aerification may be combined with dethatching to alleviate any soil compaction problems.

However, if a pre-emergent herbicide was applied late February to mid-March, postpone any cultivation practices that will disturb the soil until just before the next pre-emergent herbicide application date. Pre-emergent herbicides create a barrier that keeps weed seeds from germinating. Disturbing the soil after an application will allow weeds to emerge through this barrier. For more information on aerification, refer to HGIC 1200, Aerating Lawns and HGIC 1226, Turfgrass Cultivation.

Weed Control: To control crabgrass, goosegrass, sandspurs, and other summer annual weeds, apply a pre-emergent herbicide early in the year. Approximate times are mid-February in the coastal and central areas and mid-March in the piedmont/mountain areas. A second application is needed approximately 8 to 10 weeks after the initial application to give season long control of annual grassy and broadleaf weeds.

Apply a post-emergent herbicide as needed to control existing winter grassy and broadleaf weeds. In general, do not apply post-emergent herbicides during the spring green up of the turf. If a weed problem begins and the grass has begun to green with warmer temperatures, wait until the grass has fully greened before applying a post-emergent herbicide. In the meantime, mow and bag the weeds. Zoysiagrass is sensitive to certain herbicides during hot summer temperatures. Follow label directions for use of any herbicide and use with caution during these times. For more information on weed control, please see HGIC 2310, Managing Weeds in Warm-Season Lawns.

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Insect Control: Cold winter temperatures will usually keep insect problems in zoysiagrass at bay. As temperatures start to warm in late spring, monitor for mole cricket activity. If mole cricket activity is observed, apply a lawn insecticide if damage is excessive. If the damage is minimal, wait before applying an insecticide. This is not the best time to apply an insecticide for insect control because of cool soil temperatures and reduced insect activity. However, an early warm-up can lead to significant mole cricket activity. Heavy populations can be reduced through appropriately timed insecticide treatments during this period. For more information on mole crickets, see HGIC 2155, Mole Cricket Management in Turfgrass.

If grubs (the white larvae of beetles, such as Japanese beetles) have been a problem in previous years, monitor the grubs by cutting a square foot piece of sod on three sides and peel it back. If more than six grubs are found under the sod piece, apply a lawn insecticide labelled for grub control according to label directions. For more information on white grub management, see HGIC 2156, White Grub Management in Turfgrass.

Fertilization: Fertilization of zoysiagrass should be based on soil test results, and this is a good time to test soil. However, fertilizers containing nitrogen should not be applied during this period unless the lawn is located along the coast and no frost is predicted. If new turfgrass growth is encouraged by fertilization during the early spring and this is followed by a late frost, the result can be significant damage to the lawn. See HGIC 1652, Soil Testing for instructions on how to properly do a soil test.

Irrigation: During dormancy, water the lawn to prevent excessive dehydration. Winter desiccation can be a problem during dry winters. Watering to prevent drought stress can help eliminate turf loss during winter.

Most areas of South Carolina receive enough rainfall during the winter to avoid winter desiccation of lawns. However, this is not always the case. Monitor the winter rainfall on a regular basis and apply water to the turf if no measurable rain occurs over a 3 to 4 week period. This is especially important if warm, bright days preceed days forecasted to be in the low 20’s or colder. The added moisture in the soil will help keep the growing points of the turf warmer, preventing crown death.

To manage a lawn, it is important to know the soil texture in the top foot of soil. Sandy soils do not hold moisture well since they drain freely and dry out faster. Clay soils, however, will hold moisture for a longer period. Do not allow the lawn to stay excessively wet if the lawn has a clay soil. If the soil stays saturated all winter, this can cause many other problems. A soil probe can be used to monitor the soil moisture. For more information, refer to HGIC 1207, Watering Lawns and HGIC 1225, Conserving Turfgrass Irrigation.

May Through August

Mowing: The ideal mowing height for zoysiagrass cultivars can range from 1 to 2½ inches depending on your specific site and management. For most zoysiagrass cultivars, turfgrass growers recommend a mowing height of 1½ inches. In partial shade, mow zoysiagrass at 2 to 2½ inches. Mowing heights below 1 inch will require a reel type mower to achieve satisfactory results, and with zoysiagrass, a reel type mower will give better results at any height.

During periods of environmental stress, high temperatures, or a lack of rainfall, slightly raise the mowing height until the stress is eliminated. Always mow with a sharp mower blade and use a mulching type mower to leave the clippings to decompose on the lawn. The mower blade will need sharpening on a regular basis, which is usually about once a month. If the bagger is picking up soil, especially sand, the mower blade may need to be sharpened more often than once per month.

Fertilization: Always fertilize and add lime or sulfur based on a soil test. Zoysiagrass will grow best at a pH of 6 to 6.5. If a soil test shows a higher pH, sulfur can be applied to lower it. Apply 5 pounds of pelletized sulfur per 1000 square feet of turf. Apply sulfur only when the air temperatures are below 75 °F. In 3 months, recheck the soil pH to see what change was made. It may take several years for a large pH change to occur. Soils in the Upstate are typically acidic and usually do not need sulfur applications, but they likely may benefit from lime applications.

Zoysiagrass lawns should receive 2 to 4 pounds of actual nitrogen per growing season per 1000 square feet of turf. The higher rate may be used on zoysiagrass lawn grown on sandy soils, and the lower rate for lawns grown on clay soils. An application of a soluble iron product will enhance the green color without creating excessive growth.

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Early Summer: Apply ½ to 1 pound of actual nitrogen per 1,000 square feet early May after the lawn fully greens up. The rate will depend on soil type. A soil test will help determine if a fertilizer containing phosphorus, the middle number in the fertilizer analysis, is sufficient for the lawn. See the section on fertilizer calculations below to determine how much granular fertilizer product should be applied.

Mid-summer: Depending on the soil type, fertilize with ½ to 1 pound of actual nitrogen per 1,000 square feet in June or July using a fertilizer that is also high in potassium, such as a 15-0-15. The need for phosphorus is determined by a soil test.

Late Summer: Depending on the soil type, apply ½ to 1 pound of actual nitrogen per 1,000 square feet before August 15 using a fertilizer that is also high potassium, such as a 15-0-15. It is important for the soil to have sufficient potassium, especially late in the growing season as the grass enters dormancy. Potassium is important for disease resistance and cold weather hardiness.

Nutrient Deficiencies: A yellow appearance during the growing season may indicate an iron deficiency due to excessive soil phosphorus and/or a high soil pH. A long-term approach is needed to correct either cause, but iron can be added to quickly enhance turf color between the spring and summer fertilizer applications.

Note: A yellow appearance may also arise in early spring. This could indicate an iron or manganese deficiency due to soil temperatures lagging behind air temperatures, high pH soils, or high phosphorous levels. Spraying with iron (ferrous) sulfate) at 2 ounces in 3 to 5 gallons of water per 1,000 square feet or applying a chelated iron product will help to enhance turf color. Fertilizing with a micronutrient fertilizer, such as manganese sulfate, can help alleviate manganese deficiencies. However, as the soil temperatures start to climb, the yellowing should slowly go away. Lime or sulfur may also be added if a soil test indicates a need. Be aware, it could take several months for lime and sulfur applications to begin to affect the soil pH.

Fertilizer Calculations: To determine amount of granular fertilizer needed to apply ½ pound of actual nitrogen per 1,000 square feet, divide 50 by the first number on the fertilizer bag. To determine amount of product required to apply 1 pound of actual nitrogen per 1,000 square feet, divide 100 by the first number on the fertilizer bag. This will give the number of pounds of fertilizer product to apply to 1000 square feet of turf. See HGIC 1201, Fertilizing Lawns, for more information.

Irrigation: Water to prevent drought stress. Monitor the lawn on a regular basis to assess the need for irrigation. When the entire lawn appears dry, apply ¾ to 1 inch of water the next morning. Wait to irrigate again when the lawn shows moisture stress. There are several ways to determine when the lawn needs watering. One way is to monitor the lawn daily. When the turf begins to dry, it will appear to have a bluish color. Another method is to walk across the lawn late in the evening. If the grass blades in the footprints rebound, there is plenty of moisture in the turf. If the grass in the footprints do not rebound, then water the next morning.

The irrigation interval will vary from site to site depending on the environmental conditions at that site and soil type. The general rule to turfgrass irrigation is to water “deeply and infrequently”. Localized dry spots or hot spots can be watered by hand as needed, but only run the irrigation system when the entire lawn is dry. For more information on turfgrass watering, see HGIC 1225, Conservative Turfgrass Irrigation.

Insect Control: There are various insect pests that may attack zoysiagrass during the summer months. Mole crickets, grubs, ground pearls, as well as nematodes can cause considerable damage. Each pest problem will have its own management strategy and is usually handled with cultural and chemical controls. However, there can be exceptions. Mole crickets and grub eggs will usually hatch mid-summer. An insecticide application targeted at the smaller nymphs is the most effective control even if damage has not yet occurred. If either of these insects were a problem early in the season, apply an insecticide mid-July to control the younger immature insects.

If an insect problem occurs, it is important to positively identify the problem and select the appropriate insecticide to apply. Contact the local County Extension Office or the Home & Garden Information Center for positive identification and proper management strategies. For more pest management information, see HGIC 2156, White Grub Management in Turfgrass, HGIC 2155, Mole Cricket Management in Turfgrass, and HGIC 2157, Bermudagrass Scale, Rhodesgrass Mealybug & Ground Pearl.

Disease Control: The most common diseases that may occur on zoysiagrass during the growing season are large patch, formerly known as brown patch, and dollar spot. Large patch and dollar spot are fungal disease that will occur during warm, wet weather. Since they are fueled by moisture, it is important to use proper watering practices, as well as providing adequate soil drainage.

If the turf does stay wet, circular areas may start to develop and slowly grow in size. Diseased turf with dollar spot range from 2 to 6 inches in diameter, but large patch may result in affected areas that may grow to several feet in diameter. The center of a large area may start to green. In heavily infested turf, the areas may grow together and thus will not appear circular. If the turf at the edge of the dying area shows a smoky brown, rotted appearance, it will be necessary to apply a fungicide treatment. Overall, proper water management and thatch control is essential to curtail large patch and dollar spot problems. To help reduce disease problems, fertilize the zoysiagrass lawn according to recent soil test recommendations and water infrequently.

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Weed Control: A selective, annual grass or broadleaf weed control pre-emergent herbicide that is labelled for use on zoysiagrass and applied during late winter and spring will reduce many weeds the following summer. If a pre-emergent herbicide was not applied, then the resulting weeds will need to be controlled using post-emergent herbicides

Broadleaf summer weeds, such as spurge and annual lespedeza, are controlled by using a 3-way, broadleaf weed herbicide. These 3-way mixes typically contain 2,4-D, dicamba, and mecoprop.

Many grassy weeds are controlled by quinclorac or fluazifop applications. Nutsedges are controlled by imazaquin, bentazon, or sulfentrazone. If summer annual grassy weeds are a problem, pre-emergent herbicide applications in late winter and early spring may be the best choice.

Do not apply herbicides in summer unless the temperature is below 90 °F. Use herbicides with caution as the turf is emerging from winter dormancy. Do not mow the lawn for 3 days prior to or 2 days after herbicide application. For best control and to lessen the chance of turfgrass injury, always apply herbicides to turfgrass and weeds that are actively growing and not suffering from drought or heat stress. As with all pest control, proper weed identification is essential. Contact the local County Extension Office or the Home & Garden Information Center for identification and control of weeds in the lawn. For more information on weed control, see HGIC 2310, Managing Weeds in Warm Season Lawns and HGIC 2312, Nutsedge.

Renovation: Replant large bare areas in May using sod, plugs, or sprigs (5 bushels per 1,000 square feet). Zenith zoysiagrass is available as seed and is best planted in late spring or early summer. For more information, refer to HGIC 1204, Lawn Renovation.

September through December

Mowing: Continue to mow the zoysiagrass lawn at the normal mowing height until the weather starts to cool in the fall. Once nighttime temperatures fall below 70 °F, slightly raise the mower to allow more leaf surface. This will allow the turf to become acclimated by the time the first frost occurs.

Fertilization: Do not apply nitrogen at this time. Lime or sulfur may be added if recommended by a recent soil test. Potassium, commonly known as potash, may be applied to enhance winter hardiness if a soil test indicates insufficient levels of potassium. Apply 1 pound of potash (K2O) per 1,000 square feet 4 to 6 weeks before the first expected frost by using 1.6 pounds of muriate of potash (0-0-60) or 2 pounds of potassium sulfate (0-0-50) per 1000 square feet.

Irrigation: In the absence of rainfall, continue to water to prevent drought stress. After the lawn has become dormant, water as needed to prevent excessive dehydration. This is especially important if warm, bright days preceed days forecasted to be in the low 20’s or lower.

Insect Control: Any insects that were missed during the nymphal stage in the summer will have grown to a size where damage is occurring. Apply an insecticide to reduce the population and reduce further turf damage. This is best done before the first frost.

Disease Control: For disease control, especially large patch, it is extremely important to treat with fungicides during the fall months. With warm temperatures through September and the possibility of excessive rainfall that may occur during that period, diseases can spread rapidly. However, with cooler nights and shorter day lengths, control can be quite difficult because of slow turf recovery during this time. Turf weakened by disease in fall will be slow to recover in the spring; therefore, fungicide applications are needed to control disease before the grass goes dormant. In certain situations where large patch has been prevalent yearly, a preventative fungicide application may be needed starting in early October to stay ahead of the disease. For more information on disease control, please see HGIC 2150 Brown Patch & Large Patch Diseases of Lawns.

Weed Control: Many winter annual grassy and broadleaf weeds can be managed by applying a pre-emergent herbicide in September with a second application 8 to 10 weeks later. Follow all label directions on the product for use and application rate. Granular herbicides must be watered into the soil soon after application. Follow label directions as to post application watering.

Broadleaf weed herbicides can be applied as necessary for control of chickweed, henbit, and other cool-season broadleaf weeds. Selective herbicides can also be applied during winter for control of annual bluegrass and other winter annual grassy weeds. Contact the local County Extension office or the Home & Garden Information Center for weed identification and control measures. See for HGIC 2310, Managing Weeds in Warm Season Lawns for more information.

Originally published 09/05

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