Propagation of Bentgrass

By: Brian Nordick

The creeping bentgrass is a perennial cool season grass that forms a dense mat. The grass spreads by profuse creeping stolons and possesses rather vigorous, shallow roots. Stems(stolons) are decumbent(creeping) and slender and produce long narrow leaves. Leaf blades are smooth on the upper surface and rigid on the underside, 1 to 3mm wide and bluish green in appearance.

Creeping bentgrass is adapted to cool, humid environments such as those found in the northeastern United States. Cool nighttime temperatures are particularly advantageous to bentgrass.

Propagation. In the case of bentgrass, particular attention needs to be given to seedbed preparation. Well drained soil mixtures are essential for growing bentgrass in the South. Highly permeable mixtures of sand and organic amendments placed over a drainage system are commonly used for bentgrass green construction.

Seeding rates for bentgrass golf greens vary from 0.5 to 1 pound per 1,000 sq. ft. If mulch is applied over the seed, about 50 pounds mulch per 1,000 sq. ft. are used. Light, frequent watering is necessary on these highly permeable green's mixtures to keep the seedbed moist. The mulch may reduce the frequency of watering from 5 to 7 times per day to 2 to 3 times per day. Under ideal conditions germination may begin five days after seeding.

Frequent fertilization is also helpful to establish a cover of bentgrass on these sand mixtures. A starter fertilizer might be applied before seeding and one month later. Soluble nitrogen fertilizers can be applied at light rates at 10-day intervals after seeding until a complete cover develops.

Early fall is the best time to seed bentgrass in the South. Spring planting dates do not allow adequate growing time for plants to mature prior to summer stress.

Management Water must be closely managed to meet the moisture needs of the grass, but not exclude oxygen from the soil. Water also serves to moderate the temperature during heat stress periods. Watering schedules and rates must be based on water use rates (evapotranspiration) and the water holding capacity of the soil. During summer months, watering practices may determine success of failure with bentgrass. Well drained greens (permeable soil mixtures and good surface runoff) and well designed irrigation systems give the turf manager an edge on bentgrass greens. At times little or no irrigation may be needed; at other times, very light applications of water (misting) may be needed to cool the turf by evaporation from the leaf surface.

The turf manager must closely manage the water needs of bentgrass during heat stress periods. Excess water, or saturated soils, can be as damaging as insufficient water during heat stress. The successful turf manager matches irrigation rates to water use rates (evapotranspiration) and uses a misting system to cool the turf during mid-day stress.

Fertilization practices are also critical on bentgrass greens. The successful manager plans fertilizer applications to promote growth without depleting carbohydrate reserves. During cool periods such as fall and early spring, fertilizer promotes stolon and leaf growth as well as carbohydrate storage in stolons. However, late spring and summer applications of fertilizer promote leaf and stolon growth at the expense of carbohydrate reserves. Thus, very little fertilizer should be used between June and September on bentgrass greens.

In addition to nitrogen, potassium, phosphorous, and iron are required on most golf greens. Soil and plant tissue analyses will alert the turf manager to specific needs of bentgrass for these nutrients. On an annual basis, 1 to 2 pounds of phosphorous, 4 to 5 pounds of potassium and several foliar applications of iron are generally needed. But, soil and tissue samples will indicate specific nutrient needs.

Mowing heights of 3/16-inch or less are common on bentgrass greens. But, during summer stress periods raising the height to 1/4 inch helps the bentgrass survive heat stress and tolerate wear.