The Iowa Gardener: Beautiful lawns are made in the fall

What lawn professionals have long said is true: Beautiful lawns are made in the fall.

That's because when you fertilize a lawn in the fall, grass plants are in a mode of taking nutrients down into their roots for storage — compared to spring and summer when it is taking up nutrients mainly to its leaves. That makes the fall fertilizer application especially important because it helps build the grass plant's food reserves and promotes strong plants and early green-up next spring.

If you use a lawn service, double check to make sure it does a fall fertilizing. Also ask about organic alternatives. An increasing number of lawn services gift customers a choice of synthetic chemical fertilizers or organic fertilizers.

Or apply your own fall fertilizer. Most garden centers carry a wide selection, both organic and synthetic. Read labels carefully and follow the directions to the letter. More is not better and incorrect application can “burn” your lawn, creating brown spots.

Fall also is the ideal time to plant seed or lay sod. Lawn grass is a cool-season plant and by September, we’re past those long, extremely hot stretches of weather. Not only does hot weather stress lawns, but grass seed won’t germinate if it’s very hot, needing daytime temperatures between 60 degrees and 75 degrees. Newly laid sod also appreciates the cooler temperature.

Fall also is an excellent time to control many weeds in the lawn.

If you are using a lawn service, check to see if they use any type of broadleaf herbicides. (Broadleaf herbicides kill plants with broad leaves, like creeping charlie and dandelions, but not plants with skinny leaves, like turfgrass.) Because plants are taking up nutrients to their roots for overwintering, when weeds are treated with herbicide, they take up the weed killer also to their roots, which eliminates them more effectively.

There are now some organic broadleaf herbicides, but they are generally not as effective as synthetic chemical herbicides. Broadleaf herbicides can hurt grass seed, so either contact your lawn service if you are doing any seeding or read the label to see how application of an herbicide should be timed with grass seed sowing.

If your lawn is small, you can also control weeds somewhat simply by pulling them, especially if you do so after a good rain when the ground is soft.

While the rest of your garden may be going dormant, lawns benefit from continual care until the first frost. Continue to water as needed to create the equivalent of an inch of water every week if temperatures are hitting the 80s; once every 10 days or so is usually fine if daytime highs are lower.

Also continue to mow. Grass is healthiest when it is regularly mowed and when you are not removing more than one-third of the leaf blade at a time. It's also healthiest if you mow it at least 2 to 3 inches tall. Taller grass creates light shade, which prevents weeds from taking hold and keeps the soil cooler and moister. If you bag your clippings, mowing also collects leaves.

This is important because a heavy layer of leaves suffocates lawns, making it prone to fungal diseases or killing it outright. If you don't mow and bag, be sure to rake up leaves.

If you have a gas-powered mower, after the last mowing of the season, run the mower until the gas tank is empty for winter storage. Follow manufacturer directions on cleaning any filter/changing the oil.

If you have an electric mower, remove the battery and store it in a frost-free spot. Extremely cold temperatures can damage the battery.

Then remove the blade and have it professionally sharpened (check with your local hardware store) so it's ready for next year. A dull blade rips rather than cuts grass leaf blades, making them heal unevenly and giving lawns a beige cast, and promotes disease problems.

Fall lawn care in Iowa is all about preparing your yard for the challenges of winter while laying the groundwork for a vibrant spring. Some basic care now will ensure a healthy, beautiful lawn next year.

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Veronica Lorson Fowler is copublisher of the Iowa Gardener website at www.theiowagardener.com.