The days are warmer and the lawn is beginning to turn green again.

Mowing the lawn begins soon. To enhance the cool-season lawn and protect the environment, use the best management practices, which include avoiding fertilizer in the spring and proper mowing.

Best management practices protect the environment and may save money.

The best time to apply nitrogen to the lawn is in the fall. The grass develops a deep root system and becomes very dense to crowd out spring weeds. Nitrogen applied in mid-spring causes problems including excessive grass growth. No more than one-third to one-half of leaf material should be removed at one time.

Another tip is to make sure the mower blade is sharp before beginning to mow. A dull blade tears the leaves making the lawn look ragged and making it more susceptible to disease. A dull blade also increases the fuel used by the mower. It is highly recommended to sharpen the blade four to six times per year for a better lawn.

Mowing height recommended for tall fescue is 2 to 3 inches; for Kentucky bluegrass the recommended height is 2 to 2.5 inches. Mowing at the best height for the grass encourages a deeper root system, which helps protect your lawn against drought and weeds.

If your mower has a fixed, all-year height, set it at 2.5 inches. However, if you can easily vary the height, set it at 1.5 to 2 inches for the first several mowings. The shorter mowing height removes a lot of winter-burned, brown leaves.

Exposing more dark green growth transforms the lawn into the most uniform, attractive one in the neighborhood. After several mowings, move the height up to 2.5 inches.

When summer arrives, protect your grass from summer heat and drought injury by raising the mower height to 3 or 3.5 inches. However, remember that extra-high grass, especially tall fescue, tends to fall over and mat down during hot summer weather, causing increased summer disease problems.

Another tip is to mow often so that only one-third of the grass blade is removed at any one time. Removing too much leaf tissue at once decreases spring root growth and summer drought tolerance and increases weed and disease problems.

In spring, the lawn may need to be mowed more than once a week. Mowing off more than 50% of the leaves at one time causes scalping, resulting in increased weed competition and death of some grass plants during the hot summer.

Another popular question is “What should be done with grass clippings?” Leaving them on the lawn saves time, money, and energy, since you don’t have to stop and empty the bagger or buy trash bags. Clippings also add free fertilizer to the lawn, possibly as much as 25% of the lawn’s annual nutrient needs. Remember, grass clippings are not accepted in the garbage.

Grass clippings do not increase thatch. Clippings contain 75 to 85% water and decompose quickly. Thatch is a tight, intermingled organic layer of dead and living shoots, stems, and roots that develop between the green leaves and soil surface. About a half-inch of thatch is normal. It helps moderate temperature extremes and provides a cushion effect at the soil surface. A lawn of tall fescue grass generally does not have a serious thatch problem.

Short grass clippings decompose more quickly. A mulching mower or blade, while not necessary, cuts or shreds the leaves into small fragments.

Collecting grass clippings may be necessary when the grass is tall and normal mowing tends to windrow the clippings, smothering the grass underneath. The collected clippings can be used as a mulch around ornamentals and between garden rows to a depth of 1 inch. Do not mulch with clippings from lawns that were treated with an herbicide to control weeds or contains seed heads of weeds.

Early spring or fall is a good time to aerify a lawn if the soil is compacted. The soil is considered compacted if you are not able to push a pocketknife blade into moist soil with your thumb, gently. Plugs of soil must be removed to be beneficial. As a note, most lawns do not require aerification because there is not enough traffic to compact the soil.

For more information about management tips for the lawn, contact the Daviess County

Cooperative Extension Service at 270-685-8480 or “Considering the Environment in the Maintenance of Your Kentucky Lawn: A Season by Season Approach” is available at or at the office.

Annette’s Tips

Crabgrass begins to germinate when the soil temperature is between 57 and 64 degrees at the 1-inch soil level. The UK ag weather website,, provides a map with soil temperatures from across Kentucky.

A good rule of thumb is to make sure the pre-emergent herbicide is applied by the time forsythia shrubs begin to drop their blooms, with another application about one month later.

Try to use a pre-emergence crabgrass preventer without nitrogen. Read and follow label directions. Only specific herbicides for crabgrass prevention can be used when seeding a new lawn without damaging the seedlings. Do not apply the crabgrass herbicide before a heavy rain because it may wash away, thus carrying it off-target.


pcoming Event

A commercial marketing possibility for local farm-raised products is through the Owensboro Regional Farmers’ Market vendor virtual signup meeting on March 9 at 6 p.m. Registration for the meeting is located at

Annette Meyer Heisdorffer, PhD, is the horticulture extension agent with the Daviess County Extension Office. She can be reached by calling 270-685-8480.

Annette Meyer Heisdorffer, PhD, is the horticulture extension agent with the Daviess County Extension Office. She can be reached by calling 270-685-8480.


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