Best time for sowing new grass is here

Topeka Capital-Journal, The, Aug 23, 2008

Tall fescue lawns can become thinned out due to heat and drought stress, insect damage or disease.

Because tall fescue is a bunch grass, it may need to be overseeded to thicken up a thin stand, and September is the prime time to overseed tall fescue lawns. But simply throwing seed onto an unprepared seedbed is a waste of time, money and effort.

To properly prepare a lawn for overseeding, mow down to about 11/ 2 inches, and collect clippings in the process. Then rent a vertical slicer with thin, sharp blades to cut shallow grooves into the soil surface. Pick up the debris that is lifted out during the first pass with the slicer. Then use the slicer to make a second pass, perpendicular to the first.

Broadcast seed at a rate that reflects the extent of the existing stand. A full seeding rate for new plantings of tall fescue is 6 to 8 pounds per 1,000 square feet.

If the area you need to re-seed has about a one-half stand of grass uniformly distributed throughout, use about one-half of the full rate, or 3 to 4 pounds of seed per 1,000 square feet.

Bare areas need a full seeding rate, but that's hard to calculate when dealing with small, irregular spaces. And planting grass seed too thick is a common problem that leads to disease, matting and competition within the stand.

When tall fescue seed is uniformly distributed at the recommended seeding rate of 6 to 8 pounds of seed per 1,000 square feet, there should be 12 to 15 seeds per square inch.

Some people go back over the seeded area with the slicer to work the seed down to the soil surface. A small drag mat or even the back of a broom rake also can be used to work in the seed.

Lawn cultivation equipment -- There seems to be some confusion about equipment used to cultivate established lawns.

Many people understand what a core aerator is and its purpose for opening up compacted soil.

But the term "power-rake" is loosely used to refer to several types of equipment.

A common type of power rake is a unit, that consists of a cylinder with heavy metal, swinging "flail" type blades that literally beat out thatch and accumulated debris.

A vertical slicer or "verti-cut" machine possesses a cylinder fitted with thin, sharp metal blades that are securely attached to the cylinder so they cut grooves into the soil surface as the machine moves forward.

A properly adjusted power rake can help to lift thatch, mat and surface debris out of a fescue or bluegrass lawn. But care must be exercised to avoid doing excessive, irreversible damage to the lawn in the process.

A vertical slicer is also the best implement for preparing the surface of an existing lawn for over-seeding because of the grooves it cuts into the soil surface, creating ideal places for seed to fall into direct contact with the soil.

Part of the confusion surrounding the names applied to this equipment is because both types may be interchangeable units that fit the undercarriage of the same machine, so you can't tell the difference until you tip the machine up and look underneath.

Selecting a turfgrass -- The most popular turfgrass species used for residential lawns in northeast Kansas is tall fescue.

For many years, the variety Kentucky-31 was used for lawns, even though it was developed as a forage grass. K-31 made an acceptable lawn, but some people objected to the coarse texture of its wide- leaf blades. Another problem with some seed lots of K-31 has been contamination with undesirable off-types like this clump of orchardgrass.

In response to public desire for a more refined tall fescue variety, plant breeders came up with a couple of "turf-type" varieties named Rebel and Falcon that were introduced in the early 1980s.

Since that time, many other superior strains have emerged that possess better color, and have narrower leaves.

The trend today is to plant a blend of three or four these high performing turf-type varieties to capitalize on their individual attributes and dilute their deficiencies. By spreading out the genetic base, it may be possible to introduce a broader range of adaptability and disease resistance. Pre-formulated proprietary blends are available at most garden centers, or individual varieties can be combined into a custom blend.

Because the leaf blades of turf-type tall fescue varieties are narrower than the old K-31 variety, they have been mistakenly referred to as "fine-leaf" fescues. True fine-leaf fescues are the red, hard and sheep fescues, which don't perform well in our area. Turf-type tall fescue varieties shouldn't be referred to as "fine" fescue because it just confuses the issue.

For a printed list of recommended tall fescue varieties, call the Shawnee County Extension Master Gardener Response-Line at 357-GROW any weekday afternoon.

Phil Sell is a retired agent emeritus with K-State Research and Extension.