There are many varieties of turf grasses. Before choosing the best grass for your location and needs, it helps to know a little about grasses in general. To begin with, grasses are either cool-season or warm-season.

Cool-season grasses grow fastest in spring and tend to go partially dormant in the heat of the summer. In the Denver area, cool-season grasses normally start to turn green in late March and stay green until November.

Warm-season grasses green up around mid-May, grow fastest in summer, and go dormant with the first hard frost, usually in early October. They tend to have a light tan color while dormant.

Grasses are also categorized as either sod-forming or bunch grass. A sod-forming grass will spread, eventually forming an interwoven "mat" of grass. Bunch grass will not spread — each grass plant remains separate from its fellow plants.

There is no such thing as the "perfect" grass — every grass species has its good and bad points. Know your turf to help you select the best grass for your particular situation. Also check with your landscape professional for other turf options.

Along the Front Range, top soil is typically one of two kinds: heavy clay or sandy. Neither kind is ideal for turfgrass. New construction sites face a greater problem, since most of the existing top soil is removed during the construction process and the soil left behind is compacted by construction traffic.

To perform well, turf needs a minimum of four to six inches of loose, amended soil. Lack of initial soil preparation is a major reason for subsequent lawn failure.

To prepare the soil for seed or sod, do the following:

• Clear the site of any debris, stones, etc. If there is existing turfgrass that will be replaced, either use a sod cutter to remove the turf or use a non-selective herbicide to kill it.
• Eliminate weed problems prior to seeding or sodding.
• Grade the area to eliminate any drainage problems.
• Apply a "starter fertilizer" that contains nitrogen and phosphorus, using the recommendations for the particular product.
• Add one to two inches of soil amendments — such as compost, sphagnum peat or aged manure — and rototill to a depth of six to eight inches or as deeply as possible. Three cubic yards of amendment will cover 1,000 square feet to a depth of one inch.
• Finish grading the site.

To seed a lawn, sow the recommended pounds of seed per 1,000 square feet uniformly across the area. For more uniform coverage, seed in two directions: north-south and east-west, using half the allotted seed in each direction. After seeding, lightly rake the seed into the soil, being careful not to go too deep. If desired, cover with a light mulch of straw or sphagnum peat moss. Finally, use a roller to firm the soil surface.

To install sod, start with the longest straight line (i.e. along a driveway or sidewalk). Push ends together tightly, but avoid stretching the sod. Stagger the end joints in each row of sod, as if you were laying brick, and try to avoid leaving small strips at outer edges.

After laying the sod, use a roller to ensure good soil contact and level out any uneven spots, then water thoroughly.

A newly-seeded lawn must be kept moist, but not saturated, until the seeds germinate. Depending on the weather and site conditions, this may mean watering for a short time several times a day. As the grass begins to grow, reduce the frequency of watering. After four to six weeks, watering should be reduced to the amount recommended for an established lawn.

New sod must be watered enough to ensure that the soil beneath the sod stays moist without becoming waterlogged. Water twice a day (early morning and late evening is preferable) for the first week, and once a day for the second week. At this point roots should be established in the new soil and watering can be reduced to the amount recommended for an established lawn.

If you have an automatic sprinkler system, be sure to reprogram it at this point to water based on the ET (evapotranspiration) rate.