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The Journal Gazette

Saturday, April 20, 2019 1:00 am

How we treat lawn affects all

Ricky Kemery

Question: How has the cool spring affected what we will do for lawn maintenance this year?

Answer: The cool weather followed by more normal temperatures will compress the gardening season as it has done in the past. To better understand lawn care, one needs to understand when the lawn is at its “happiest” and when care is needed. More and more, citizens need to understand that they must be stewards of the environment and strive to understand that their lawn care management methods affect everyone.

Lawns will begin to grow in earnest when daytime temperatures are reliably in the 60s and soil temperatures reach 55 degrees. This is because photosynthesis – using energy from the sun to make sugar for plant processes – begins when temperatures are above 55. These conditions are when turfgrass is at its happiest. Beginning in mid-April the lawn will need its first mowing and fertilization. A slow-release fertilizer should be used to reduce nitrogen and phosphorous from entering watersheds such as ponds, rivers and lakes.

Broadleaf weed control and crabgrass are always an issue with homeowners. In my opinion, treating the entire lawn for crabgrass just because it is on a “schedule” is a waste of resources. If crabgrass has not been an issue, then I would spot-treat any areas with a post-emergent control if crabgrass appears later in stressed areas. Instead of treating the entire lawn for a few broadleaf weeds, I would again spot-treat those weeds instead of treating the entire lawn. If you have a healthy lawn, then weed pressure should be minimal. As I have mentioned in previous articles, pesticides that kill things do have an impact on everyone who is exposed – including all your neighbors who breathe the drift and track in the pesticide after it is applied. Children and pets are especially vulnerable to broadleaved pesticide residue.

The forecast for this summer is for above-average temperatures with average precipitation. Mid-summer is when lawns are the most unhappy. This is because bluegrass grows best when it is cool. When daytime temperatures are 80 degrees and higher, the lawn slows down and sometimes just stops. In general, it is not a great time to push the lawn with fertilizer – unless there have been periods of heavy rainfall. I would not treat the lawn with preventative grub controls unless grubs and Japanese beetles are an issue. These types of pesticides are especially toxic to bees.

Early fall and late fall are especially good times to fertilize the lawn. Research has shown that the turf uses the nutrients from the fertilizer to grow healthy roots, even in the following spring.

More lawn care companies now offer organic lawn care or hybrid care with some organic and conventional lawn maintenance. Your lawn might not be quite pristine, but in the big scheme of things what is better? A perfect lawn that requires major pesticide and fertilizer input, or a healthy, less perfect lawn that is more environmentally friendly for everyone?

The Plant Medic, written by Ricky Kemery, appears every other Saturday. Kemery retired as the extension educator for horticulture at the Allen County branch of the Purdue Extension Service.