Released: February 15, 2002

Also see: Early Spring, 2002 Yard 'n Garden news package

Spring’s Care May Determine Turf’s Health, Quality, Lifespan

MANHATTAN, Kan. – Lawns are at risk now in the U.S. Heartland. Homeowners hoping to reduce the odds for losing lawn quality – or the turf itself – are facing some tricky decisions.

"Most of Kansas has spent the winter getting abnormally dry or entering the early stages of drought. Compounding the situation, many Kansas lawns grow in compacted soils. This year’s repeated freeze-thaw cycles haven’t been healthful for turf, either. I have to suspect we could be facing some problems," said Matt Fagerness, horticulturist at Kansas State University.

Depending on the amount of water they applied during winter warm spells, Kansans already may have lost some turf at root level, Fagerness said.

"Basically, long-range weather forecasters now are saying that spring and summer’s weather is anyone’s guess. In Kansas, however, the great majority of lawns are tall fescue or Kentucky bluegrass. So we know spring will be our best chance to help lawns recover enough to handle any hot or dry weather ahead," Fagerness warned.

Proper irrigation and mowing will be vital, he said. Kansans’ other choices for spring will include:

* Core aerate - BEFORE doing any fertilizing, seeding and/or spraying (typically in March) to 1) reduce soil compaction, 2) break up any water-repelling thatch buildup, 3) almost immediately improve root health, and 4) allow better access for everything from moisture to grass seed or fertilizer.

* Fertilize - AFTER the turf finishes its mid-spring flush of growth (usually early May), using a slow-release nitrogen source or a slow- and fast-release mix to replenish food reserves lost during this winter’s warm weather. (Warning: Feeding too early will cause a growth frenzy that leaves turf shallow-rooted and without reserves.)

Homeowners also can take one – but not both – of the following steps:

* Overseed - BY MID-SPRING (March or April) if an emerging lawn appears so thinned by winter’s stresses that springtime care may not be enough to help it recover.

* Spray the competition - BY APRIL FOOL’S DAY to prevent the emergence of crabgrass, foxtail and other warm-season annual grasses. (Warning: Preventer herbicides can make overseeding during the same season a waste of time.)

"I’d say core aerating and fertilizing are essential to achieving a quality lawn this year," said Fagerness, who is a K-State Research and Extension turfgrass specialist. "The decision between overseeding and applying a pre-emergence herbicide is a harder one. If given half a chance, though, turf can surprise you with its ability to come back. So, in most cases I’d recommend homeowners control the weeds, rather than plant more turf."

He emphasized, however, that the impact of annual maintenance chores relates directly to whether week-to-week lawn care is on-target.

"Nothing lives without water. For best health, fescue and bluegrass need to get about 1 to 2 inches of water per week – through irrigation or rainfall – applied slowly enough that moisture can be absorbed down 6 to 8 inches into the soil," the horticulturist said. "Exceeding that amount can actually harm, rather than help lawns in Kansas. Watering often for shorter amounts of time promotes shallow, weak root growth – which is exactly what you need to kill a cool-season turf during hot, dry summers."

Lawn mowing also can help or hurt turf.

Research has found the ideal heights for all kinds of lawn turfs and growing conditions. In Kansas, for example, homeowners shouldn’t mow actively growing bluegrass varieties any shorter than 2 to 2.5 inches. Fescue lawns should stay at least 3 to 3.5 inches tall.

Research also has come up with the overall lawn-mowing Rule of Thumb: Never remove more than one-third of the turf’s leaf height at any one mowing.

"If you consistently ignore those guidelines, that alone can be enough to put your lawn at risk. Typically, your first outcome will be thin, stemmy turfgrass or a weed invasion," Fagerness said.

At the same time, however, being mowed short during cool weather encourages turf to thicken up. Being mowed on the high end of the recommended range – no matter the temperature – fosters the deep root growth, and that’s what helps cool-season turfs survive weather extremes.

"This is one year I may actually recommend that people mow a bit short through March, just to promote turf density," Fagerness said. "It’s sort of a tradition in Kansas to set your mower low in early spring. People want to remove all the dead and dormant foliage, help the soil warm up faster, and get their lawn looking green.

"I don’t argue with the practice for the first few mowings, because people usually aren’t removing more than a third of the height on short, emerging turf. I rarely recommend the practice, though, because so many people wait too long or simply forget to raise their mower height later. Ideally, Kansans should be mowing high – resetting their mower and encouraging turf’s deep root growth – by no later than April."

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K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and regional research centers statewide. Its headquarters is on the K-State campus, Manhattan.

Story by:
Kathleen Ward, Communications Specialist
kward@oznet.ksu.edu
K-State Research& Extension News