Denny's Soapbox

The fall season provides optimum conditions for lawn renovation practices. The aims are to return the lawn to 100% grass cover of desirable species.

Late Season Fertilization (LSF) for Cool Season Grasses

Turf managers have utilized late season nitrogen fertilization, sometimes referred to as fall fertilization, for years. This type of fertility program involves the application of much of the season’s nitrogen during the late season months of September through December. It is important that late season fertilization not be confused with dormant and / or winter fertilization. The latter method implies that fertilizer applications are made after the turf has lost most or all of its green color and is not actively growing. This differs notably from the late season concept, which requires that nitrogen be applied before the turf loses its green color in the late fall.

Late season fertilization is popular because many of the agronomic and aesthetic advantages attributed to its use are not realized when spring and/or summer fertilization are practiced. Advantages of the late season concept include:

• Better fall and winter color

• Earlier spring green-up

• Increased shoot density

• Improved fall, winter, and spring root growth

• Enhanced storage of energy reserves (carbohydrates) within the turf plant

Quality

Turf fertilized in September and again during October, November, or December is generally shown to possess better fall and winter color than a turf that was not fertilized at that time. In addition, signs of spring green-up have been shown to occur two to six weeks earlier if the turf has been fertilized the previous fall. Most importantly, the enhanced rate of spring greening is realized without stimulating excessive shoot growth that accompanies the early spring nitrogen applications called for in most turf fertility programs.

Timing

The late-season nitrogen fertilization concept is designed to apply nitrogen during that period of the year (late fall) that will favor root growth over shoot growth. Shoot growth of cool season grasses occur most readily in the temperature range of 50-65ºF. Root growth of cool season grasses will continue at soil temperatures close to freezing. When air temperatures in late fall consistently drop below 50ºF shoot growth slows or ceases but soil temperatures are still in the favorable range for significant root, rhizome, and stolon growth. LSF capitalizes on this differential in optimum temperatures for growth of roots versus shoots.

The timing of LSF should be made when vertical shoot growth has stopped, but the turf leaves are still green. Vertical shoot growth of cool season grasses will generally slow and stop at air temperatures of 45-50ºF. A properly timed LSF will extend the “greening” time of the turf longer into the late fall and early winter without additional top growth.

The report goes on to say you want lawn fertilizer that is quickly released and not dependent on air and soil temps. Select a fertilizer that gives you at least 1 pound of Nitrogen per 1,000 sq. ft. Shop for it at retailers that have lawn experts on hand. I personally have been on this plan for five years. I wish you could see my lawn, it’s the best on the street.

For a copy of this entire report go to http://bloomingarden.com/falllawn.html

“For more timely tips concerning what’s going on this week go to www.bloomingarden.com.”