Sometime between shopping ahead for a turkey and finishing off the Thanksgiving leftovers, Kansans need to make sure their cool-season lawn grass gets a good meal, too.
Tall fescue and Kentucky bluegrass are starving for food in early fall. But September's traditional nitrogen application is soon used up, said Kansas State University horticulturist Matt Fagerness.
"By mid to late November, cool-season lawns are growing more slowly--a real bonus during football, hunting and family gatherings," he said. "But if lawns get one final serving of nitrogen for the year, that will promote turf root growth and shoot density. Plus much of the food will end up stored in roots and crowns, where it can help with winter hardiness, plus provide an immediate and plentiful boost for spring greenup."
Waiting to fertilize in early spring can be dangerous, warned Fagerness, who is the turfgrass specialist for K-State Research and Extension. Spring feeding can promote excessive shoot growth. And that, in turn, can weaken cool-season turfs, just when they're facing summer's heat stresses.
"One pound of actual nitrogen per 1,000 square feet of lawn should be enough," he said. Just be sure it's a soluble or quick-release form, such as urea or ammonium sulfate.
"Avoid fertilizers that contain a mix of quick- and slow-release nitrogens. At best, that kind of mixture will short-change your grass. The slow-release part of your one-pound application won't get processed by soil microbes before winter, so may be lost during the cold months before spring."
Fagerness added if fescue and bluegrass lawns are still showing green, some broadleaf weeds will be green, too--and vulnerable to controls.
"This fall has provided unusually good growing conditions for cool-season turfs, as well as for dandelions, henbit and chickweed," he said. Beyond that, severe conditions last summer thinned out many established turf stands, he said So, unless those lawns have received special care since then, they have actually been giving weeds more space to grow.
Fortunately, spot treatments will kill or severely damage broadleaf weeds until the plants go entirely dormant for winter. Hand digging can be an effective dandelion control any time, so long as none of the root is left in the soil.