What is the best species of grass to grow where I live?
The turfgrasses are divided into cool-season and warm-season species. Cool-season
species do better in the cooler times of the year and thrive in temperatures
from 65° to 75° F. Warm-season grasses are best adapted to temperatures
between 80° and 95° F. The cool-season grasses grow well in the cooler
regions of the northern United States and the warm-season species are best adapted
to the warmer regions of the southern U.S. Grass species adaptation in the U.S.,
however, is a little more complicated than that, with the U.S. having four separate
climatic zones of grass adaptation. 
The cool humid zone encompasses the Northeast, several states of the Midwest, and much of the Pacific Northwest. (see map to the right) The cool arid zone includes much of the dryer areas of the Midwest and West. Cool season species such as Bluegrass, fescues, ryegrasses, and bentgrasses are best adapted to the cool humid zone; however, Buffalograss and zoysiagrass, both warm season grasses, are found in the western and southern parts of this region even though the growing season is short for these species. The cool arid zone is basically a cool-season zone and any of the cool-season grasses can be used here if irrigation is available. Buffalograss is becoming widely used in the warmer parts of the region, such as Kansas, Nebraska, and Colorado, on nonirrigated sites. Less common cool-season species such as wheatgrasses and Canada bluegrass can be found on nonirrigated sites in the cooler parts of this zone.
Warm season species are best adapted to the warm arid and warm humid regions of the U.S. Bermudagrass is the most widely used species in the warm humid zone, although it is sometimes subject to winter damage in the northern parts of the zone. Zoysiagrass is widely used in the northern parts of this zone while carpetgrass, bahiagrass, and St. Augustinegrass are more common in the Gulf Coast region. Bermudagrass is also the most commonly used species in the warm arid zone, although any of the warm-season species can be used if irrigation is available. Buffalograss is becoming increasingly important in the more arid parts of this region. In both the warm arid and warm humid zones, cool-season species are often used for winter overseeding.
The U.S. also has a region known to the turf industry as the transition zone that extends through the central part of the country and includes parts of each of the other four zones. This is the most difficult region in which to grow grass. The transition zone is cold enough in the winter to make it difficult to maintain warm-season species and warm enough in the summer to make it difficult to grow cool-season species, therefore, no one species is well adapted in this region.
What is the best cultivar of grass to grow where I live?
Turfgrass breeders throughout the U.S. have worked very hard to develop cultivars of the common turfgrass species that are well adapted to different regions of the country. In addition there is an excellent program, called the National Turfgrass Evaluation Program (NTEP), partially sponsored by the USDA that tests new and old standard cultivars of the most common turfgrass species at locations throughout the U.S. The results of these tests are available at the NTEP web site (www.ntep.org). Many of the evaluation sites are at public universities throughout the U.S., and university extension programs can generally provide data on the best locally adapted cultivars. In selecting an appropriate cultivar, it is generally best to select one that has rated high both locally and nationally, in other words, it rated within the top ten to twenty of the local test and its national average is in the top ten to twenty.
Once an acceptable cultivar has been selected, it is important to locate a source of high quality seed. Seed quality is one of the most often overlooked aspects of turfgrass establishment. If poor quality seed is selected, even the most intensive management efforts may not result in an acceptable turf. Unfortunately many home and garden supply stores do not stock high quality seed, therefore, it can be difficult to locate the seed that you want. In some locations, agricultural seed supply stores may stock high quality seed of well-adapted cultivars. The world-wide-web can also be searched to locate companies that deliver high quality seed by mail. The best way to determine if seed you are buying is high quality is to see if it has a state seed certification tag. The tag will indicate the level of germination of a selected sample and tell the relative percentage of important weeds and contaminating species.
The bag of seed I bought says it is a mixture or a blend - what does that mean?
A mixture is comprised of more than one species of grass. It is often advantageous to plant a mixture because of the increased range in genetic diversity and adaptive potential that is achieved. For example, in a lawn situation some areas may be shaded and others may receive full sun. Additionally, some areas may have a droughty, course-textured sandy soil and others may have a fine-textured poorly drained clay. A mixture containing Kentucky bluegrass and red fescue contains species that can adapt and become dominant in these different environmental conditions. Red fescue will dominate in shaded areas and on infertile droughty soils, while Kentucky bluegrass will do well in full sunlight and on imperfectly drained, moist, fertile soils. The two species may also complement each other if one of the species is seriously damaged due to injury or disease.
A blend is when more than one cultivar within a species are blended together. Blends can be useful in habitats where the environment is variable and a number of different disease and/or insect problems exist. Blends are valid where no one cultivar is resistant to all the major diseases within a habitat. If one cultivar is available that is resistant to all of the major disease and pest problems, then the use of a blend is not necessary.
What are the important things to consider when establishing a lawn from seed?
Successful establishment of a lawn from seed is a critical component of creating a healthy lawn; however, at times good establishment can even be difficult for professionals. The potential of successfully establishing a healthy turf can be increased by paying attention to a few basic principles.
Soil testing should be the first step in any soil preparation for turf establishment. A soil test should be done well in advance of planting to allow time for adding any soil amendments that may be needed. This is the best time to add fertilizer, lime, and other materials that may be needed. Rough grading of the existing soil or any new topsoil that was brought in is often necessary. In building construction, such as around new homes, where the top soil has been removed, 4 to 8 inches of topsoil should be placed on the site prior to establishment. Once the rough grading process has been completed, a starter fertilizer should be placed on the surface and not worked into the soil. A good choice for relatively fertile soils is a 12-25-10 fertilizer applied at a rate of 5 to 8 lbs of fertilizer per 1000 ft². In the case of less fertile soils, where P (phosphorus) levels are relatively low, a material like 18-46-0 applied at the same rate may be more appropriate.
The time of seed application depends upon whether the grass is a cool-season or a warm-season species. Warm-season grasses established in temperate zones should be seeded in the spring as soon as soil temperatures are high enough to achieve germination. Cool-season grasses are best established in the late summer or early fall. It is important to apply the seed using the correct seeding rate. The appropriate seeding rate is generally listed on the bag of seed. The grass seed is generally seeded on the surface and then lightly raked into the soil. The smaller the seed, the shallower it should be planted. Very small seeds like creeping bentgrass will need to be very close to the surface, whereas larger seeds like tall fescue can emerge from depths of 0.5 to 1.0 inch. The seed should also be spread as uniformly as possible by hand or using a mechanical spreader.
One of the keys to successful establishment is proper irrigation. The critical time is just after germination when the root system is not developed well enough to obtain sufficient moisture from the soil. Frequent irrigation is particularly important on warm windy days when the soil surface can dry out in a few hours. The use of mulch such as straw can also help maintain adequate soil moisture during establishment.
How often should I fertilize my lawn?
The general guideline for fertilizer application is to apply fertilizer when the turf is actively growing, therefore, the timing will be different for warm- and cool-season species. Cool-season species are most actively growing during the spring and fall of the year. However, high spring fertility treatments may be detrimental to the survival of the turf through the high stress periods of mid-summer. The general recommendation would be to apply 0.5 to 0.75 lb Nitrogen/1000 ft² in March/April and May/June and 1.0 lb Nitrogen/1000 ft² in August and September and again in the late fall. Total nitrogen applications to cool-season turf in temperate regions will generally range from 3 to 5 lb N/1000 ft² per year.
The general recommendation for warm-season turf species is 1.0 lb nitrogen/1000 ft² per growing month. This is only a guideline. On heavier soils in drier conditions this will be too much. On sandy soils during periods of heavy rainfall, this will not be enough.
It is important to remember that turfgrasses do not thrive on mowing; they tolerate it. It may seem that mowing is good for the grass, but mowing is always a stress. The cutting of leaf tissue may allow disease organisms to enter the plant, and it reduces the photosynthetic area, lowering the production of carbohydrates that the plant needs to grow. Turfgrasses are the best-equipped plants on earth to tolerate this type of defoliation. If there were better-adapted species, they would be used in the place of grasses. The mowing height that a turf will tolerate is dependent on the species that are present. The cool-season species primarily used in lawn situations are Kentucky bluegrass, tall fescue, and perennial ryegrass. These three species will do best at heights of 1.5 to 3.0 inches, with higher mowing heights used during the high-temperature stress periods. Warm-season species such as Bermudagrass and Zoysiagrass can tolerate heights of 0.5 inches or less, while Bahiagrass, carpetgrass, and centipedegrass do best at heights from 1.0 to 3.0 inches, and St. Augustinegrass should be mowed in the 3.0 to 4.0 inch range.
How often should I water my lawn?
This question does not have a simple answer because irrigation requirements vary with grass species, with soil type, and with environmental conditions. These factors often interact in complex ways that make decision making difficult. On average, turf will usually require from 1 to 1.5 inches of water per week for normal maintenance conditions. This can be provided by rainfall or irrigation or a combination of the two.
The best time to irrigate is another management decision that can impact turf quality. Overly wet conditions in the canopy can contribute to disease development. Nighttime watering will keep the turf wet for the longest period of time and should be avoided if possible. Watering during the day will allow the turf to dry quickly, but will increase water loss due to evaporation. All things considered, the early morning hours provide the best time for turf irrigation. Water loss from evaporation will be less, and the turf will dry quickly in the morning.
How can I grow grass under my trees?
It can be very difficult to maintain a turf under shade conditions. However, a few management practices can improve the overall turf condition in these areas. Shade in home lawn situations is generally provided by trees, therefore, the pruning of limbs below 10 feet from the ground and selective pruning of limbs in the crown of the tree will allow more light to reach the turf and improve turf quality.
The choice of the correct turf species can also enhance the odds of a high quality shaded turf. Red fescue is the cool-season species with the best shade tolerance and tall fescue will also do well in the shade. St. Augustine grass is the warm-season species with the best shade tolerance, but zoysiagrass will also perform well under shaded conditions.
Back to the Arboretum Home Page
Last Updated November 3, 2003 5:16 PM
URL = ../../Gardens/faqs/turfgrassfaq2.html