Submitted Photo Dandelions, shown here, and thistles are two weeds which took advantage of the hot, dry summer and appeared in home lawns. Photo from New York State IPM Program.

Fall is a very good time to do lawn chores to improve the health and appearance of home lawns. The hot, dry summer took a toll on many lawns. The cool season grasses went dormant earlier than normal. This gave weeds an opportunity to invade and spread in lawns. Dandelions and thistles were two weeds which took advantage of the situation, but other broadleaf weeds moved in as well.

Spraying herbicides on weeds after a frost can give excellent weed control. The freezing temperatures don’t harm the leaves of the thistles and dandelions, but it speeds up their preparation for winter. At this time all perennial plants are making “food” through photosynthesis, moving it to their roots, and storing it there. It will be used next spring as an energy source for the plant to begin growing again. By spraying after a light frost, the herbicide is taken in by the plant and moved down deep into the roots along with the food. In doing so, it will kill the deep roots and most time give total or almost total weed control.

Another advantage of fall lawn weed spraying is that the majority of dandelions germinate in early fall and over-winter as tiny plants. By spraying in mid to late September, not only are the adult plants killed, but these high numbers of seedlings will also be killed. This will make for an almost dandelion free lawn next year.

2, 4-D is good for lawn weed control. Follow label directions for the correct amount to use. Avoid lawn sprays that contain Dicamba. It can not only drift in the air, but can also cause damage by the roots taking up the herbicide in the soil.

Lawns should be fertilized in early to mid-September. This will help lawns build stronger root systems, make a denser sod, and improve their overall health. If possible, water the lawn soon after the fertilizer is applied to carry the nutrients into the ground. A fertilizer with 20-30 percent nitrogen and some phosphorous will work well. “Weed and Feed” fertilizer is not recommended.

Begin cutting your lawn shorter in the fall. Do this gradually so that the last mowing is 1.5 to 2 inches tall. This will discourage voles (a small rodent) from invading the lawn after the snow comes. Longer lawns provide them with cover and nest material.

Time spent this fall on your lawn will prepare it to be healthy and beautiful next summer.

Ken Eraas is horticulture assistant with NDSU Extension Service/Ward County.