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Kentucky Bluegrass

Description

Kentucky bluegrass is the second most widely grown cool-season species in North Carolina because it has a dark green color, a medium to fine texture, and, due to its aggressive rhizome system, can recover from stresses. It prefers fertile, well-limed soils and full sun to moderate shade. Kentucky bluegrass is often mixed with other cool-season grasses like tall fescue to enhance the ability of the turfgrass stand to recover from stresses. Kentucky bluegrass is often confused with tall fescue and/or perennial ryegrass. However, Kentucky bluegrass has a boat-shaped leaf tip and distinctive light-colored lines on both sides of the midrib.

lawn Maintenance for September - November

Aeration

Core lawns subject to heavy traffic or on clay soils to minimize compaction and improve rooting. Break up plugs.

Fertilization

The best way to determine your lawn's nutrient needs is by a soil test. The North Carolina Department of Agriculture, Agronomic Division, provides free soil testing. In the absence of a soil test, use a complete nitrogen-phosphorus-potassium (N-P-K) turf-grade fertilizer with a 3-1-2 or 4-1-2 ratio (that is, 12-4-8 or 16-4-8). Fertilize with 1 pound of actual nitrogen (N) per thousand square feet in mid-September and again in November (about the time the grass is green but not actively growing).

Insect Control

Check for white grubs in September and October; fall is the ideal time to control white grubs.

Irrigation

Follow watering guidelines for March through May.

Mowing

Mow to 2 ½ to 3 inches in height. Remember grasscycling and leave clippings on the lawn.

Renovation

Piedmont and Coastal Plain Regions Only! (See June-August for western region.) Overseed thin, bare areas as grass begins to respond to cooler temperatures in September and early October. Use a blend of tall fescue cultivars at 6 pounds per thousand square feet. Apply a starter-type (high phosphorus) fertilizer at time of seeding. Keep the seedbed moist with light, frequent sprinklings several times a day to ensure good germination.

Thatch Removal

It is not necessary to remove thatch.

Weed Control

Apply broadleaf herbicides to control dandelions and other weeds if necessary. Caution: Some herbicides may affect newly seeded turf. Follow label directions.

athletic Maintenance for September - November

Fertilization

Apply 1 pound of nitrogen per 1,000 square feet in September and again in November when the grass is still green but not actively growing (Refer to Table 1).

Sample the soil to determine phosphorus, potassium, and lime requirements. Obtain test kits from your county Cooperative Extension agent or from the North Carolina Department of Agriculture and Consumer Services' Agronomic Division, 4300 Reedy Creek Rd., Raleigh, NC 27607-6465. Apply lime as suggested by the soil test, but do not apply more than 50 pounds per 1,000 square feet per application. To apply more than 50 pounds per 1,000 square feet, put down split applications at least 4 weeks apart. If possible, apply lime just before soil coring to ensure deeper movement into the soil.

Use a complete N-P-K fertilizer to supply the nitrogen, phosphorus, and potassium suggested on the soil-test report. This promotes deep rooting and healthier plants. Table 1 gives examples of several fertilizers and the rates needed to supply 1 pound of nitrogen per 1,000 square feet, which is 43.5 pounds of nitrogen per acre. Use Table 2 to determine the fertilizer needed for fields of various sizes. Your county Cooperative Extension agent can help with proper fertilizer selection based on the soil test and, if necessary, a closer determination of the acreage to be fertilized.

Fertilizer Conversion Table
Fertilizer AnalysisPounds of Product
per 1,000 sq. ft.per acre
12-4-88.3360
16-4-86.3272
8-8-812.5540
10-10-1010.0435
46-0-02.295
34-0-02.9125
  1. Amount of product needed to apply 1 pound of nitrogen per thousand square feet.
  2. Amount of product needed to apply 43.5 pounds of nitrogen per acre. To determine the amount of product needed to deliver 1 pound of nitrogen per thousand square feet, divide 100 by the first number in the fertilizer ratio. For example, for a 16-4-8 fetilizer, divide 100 by 16. The result is 6.25 pounds of product per thousand square feet.

How much fertilizer do you need to buy to apply 1 pound of nitrogen per 1,000 square feet? Divide 100 by the FIRST number in the fertilizer analysis. For example, for a 16-4-8 fertilizer, divide 100 by 16 and you get 6.25. That means you need 6.25 pounds of 16-4-8 per 1,000 square feet. To figure the amount of 16-4-8 needed per acre, multiply the 6.25 pounds by 43.5 (constant), and you get 272 pounds of 16-4-8 per acre.

Typical Field Sizes in Acres
FieldSize (acres)
Baseball*Little League, Bronco1.2
Pony2
Colt3
Babe Ruth, Senior League, Official3.0 to 3.85
Infield1.2
Field Hockey*1.2
FootballPlaying surface 360' x 160'1.3
Playing surface & bench area 360' X 200'1.6
Hash mark are 300' X 54'0.37
440 Oval2.3
Lacrosse1.4
Rugby*1.4 to 1.7
Soccer*2.2 to 2.7
Softball, Adult*Slow pitch (12"), fast pitch1.5 to 2.0
Modified slow pitch (16")1.2 to 1.7
Softball, Youth*1.5 to 2.0
* varies depending on the following:
  1. size and number of fields
  2. orientation and layout of fields
  3. quality and type of support facilities
  4. internal and external buffer zones

Irrigation

If rain doesn't supply 1 to 1 ¼ inches of water in a week, irrigate in the early morning, wetting the soil to a depth of 4 to 6 inches. In sandy soils, apply ½ to ¾ inch of water every 3 to 4 days. Occasionally probe the soil to determine soil moisture. Irrigate only when symptoms of wilt appear (folded or curled leaves, footprinting, or bluish-green color). Avoid light, frequent watering, which promotes shallow rooting and algae, moss, and turfgrass diseases.

To minimize compaction and wear, do not irrigate 2 days before heavy use, and limit use of the field when it is wet. Postpone play and use other practice sites. Game fields should be used only for team play and not for team practice, gym class, or band practice.

Mowing

Cut Kentucky bluegrass to 1 ½ to 2 ½ inches and tall fescue and mixtures of tall fescue and bluegrass to 2 to 3 inches. This high cut enhances deep rooting and promotes healthier plants. Mow as often as required, but do not remove more than 40 percent of the grass height at one time. Do not allow pure stands of bluegrass to grow taller than 3 ½ inches or fields with tall fescue to grow taller than 5 inches. Clippings rarely need to be collected if this schedule is followed. Remove clippings only if they will interfere with grass growth. If the grass gets excessively high during extended wet periods, raise the mower and remove one-third of the new growth; then lower the mower to the proper height and mow again in a day or two.

Soil Cultivation

Aeration (coring) relieves compaction on athletic fields subject to heavy traffic. Aerate monthly when the grass is actively growing using ¾- to 1-inch-diameter tines that remove soil cores. Aerate the field lengthwise twice and crosswise once. To penetrate heavy clay soils, the field must be moist but not excessively wet (water several days in advance). Allow the plugs to dry, then pulverize them with a mower or power rake and redistribute them with a dragmat. More frequent coring may be necessary along heavily trafficked and compacted areas, such as around player benches, between hash marks, along sidelines, and in front of goals. Football fields may be aerated right after the last game of the season to avoid disrupting team play.

Aeration is absolutely necessary to maintain an acceptable field. Rent, borrow, or contract for these services if you do not have the equipment on hand. Do not aerate if the turf is under severe stress (extended periods of drought, etc.). It may take 3 weeks of good growing conditions for turf to recover after aeration. The field can be used while it is recovering.

Thatch removal is not usually needed for tall fescue fields but may be necessary for Kentucky bluegrass fields. Consider removing thatch thicker than ½ inch. Do not dethatch (using a vertical mower or power rake) in late spring or summer.

Weed Control

Use a combination product to control postemergence winter annuals and perennial broadleaf. Apply at the product label rate. For more difficult-to-control weeds (corn speedwell, woodsorrel, wild violets, etc.), apply half the label rate and repeat in 10 to 20 days. The herbicides listed in the table do not control grassy weeds. Do not use herbicides on newly seeded or renovated fields until new seedlings have been mowed at least three times.

Application Rates for Postemergence Herbicides
ProductAmount per acreWeeds controlled
fenoxaprop(Acclaim Extra 0.57EC)13 to 39 fluid ouncescrabgrass, goosegrass
quinclorac(Drive 75DF)1 poundcrabgrass, foxtails, clovers, dendelion, and others
DSMA*(various trade names)variescrabgrass, goosegrass, bahiagrass, dallisgrass, purple and yellow nutsedge, annual sedges, sandbur
MSMA*(various trade names)variessame as DSMA plus green kyllinga
bentazon(Basagran T/O 4S)1 to 2 quartsyellow nutsedge, annual sedge
(Lescogran 4SL)1 to 2 quarts
halosulfuron(Manage 750F)0.67 to 1.33 ouncesyellow and purple nutsedge, green kyllinga
* Tall fescue and Kentucky bluegrass have intermediate tolerance to these products. Use with caution and at reduced or minimum label rates.

Presentations

Publications

Species Data

Seedhead/Flower

seedhead is an open panicle.  spikelets are flattened, with 3-5 seeds each.

Vernation type

leaves folded in the bud

Ligule Type

membranous; very short, collar-like, 0.008 - 0.04 inches (0.2 - 1 mm) long

ligule
ligule
ligule
Growth Season/Life Cycle

cool season turf

Auricle type

absent

sheathmargin2
sheathmargin2
sheathmargin2
Leaf blade tip shape

boat shaped; usually V-shaped, sharply creased below; two distinct, clear lines, one on each side of the midrib

april 8
april 8
april 8
leaftip
leaftip
leaftip
Leaf blade width

0.08 - 0.16 inches (2 - 4 mm) wide

Stolon Presence

absent

Rhizome Presence

present

Collar Type

slightly divided by midrib, may have fine hair on edge

collar
collar
collar
Sheath Margin

closed, but splits with maturity

sheathmargin2
sheathmargin2
sheathmargin2