If you have watched television or listened to radio in the past few months, chances are you have heard at least one commercial from Scotts brand fertilizer. Their television ads feature a rugged, red-bearded Scotsman named, of course, Scott. He informs us that fall is the best time to fertilize your lawn to help grow new roots for survival during the long winter ahead.
He always ends the commercials with the catchphrase "Feed your lawn, feed it!" The main concept behind these advertisements is "winterizing."
Winterizing involves fertilizing your lawn with high amounts of nitrogen and potassium, such as a 32-0-10, with the hope that this will make the grass more cold hardy during winter. So, does winterizer fertilizer really work, or is this just a savvy marketing campaign by "big fertilizer?"
According to UGA Extension Turfgrass Specialist Clint Waltz, the biggest problem with these "winter feeding" ad campaigns is that they are much too vague as to which grass species they should be used on. Because these ad campaigns are usually run on a national level, they are not tailored to our region and plant types. The same ads that run in south Georgia are also shown in New England.
There are two basic types of grasses used in home lawns: Warm-season (bermuda, zoysia, centipede, etc.) and cool-season (tall fescue, bluegrass, etc.)
Warm-season grasses grow in the late spring and summer and go dormant in the fall.
Cool-season grasses grow best in the fall and spring.
Because they are entering dormancy in the fall, fertilizing a warm-season species at this time has the potential to injure the grass. Heavy fertilization with nitrogen fertilizer will promote new, tender shoot growth, which is susceptible to cold damage.
Cool-season grasses should be fertilized in the fall for optimum results.
Winterizer fertilizers, with their high nitrogen and potassium contents, work well to promote a healthy stand of tall fescue before the cold winter. Nitrogen encourages new blade production, and potassium has been shown to enhance cold tolerance.
Potassium could be added to a warm-season grass in the fall to help with cold tolerance, but it is very difficult to find a fertilizer containing only potassium. However, there are several cultural practices any homeowner can use to promote better cold tolerance in their turf.
Have low-hanging branches pruned and rake leaves to allow more sunlight to hit your grass. This will allow the turf to produce more carbohydrates and build thicker roots. Raising your mowing height slightly in late summer and into fall will promote deep rooting just before winter.
It is important to do your research before using any type of fertilizer on your home lawn. Try not to be swayed by slick commercials, and only fertilize your lawn according to recommendations from a soil test.
Always look at the analysis on the fertilizer bag, expressed as three numbers: Nitrogen-phosphorous-potassium.
Even though the Scotts brand commercials are technically true, they should be more specific as to which types of grasses they are to be used on. Only use "winterizer" fertilizers on your cool-season grasses.