Lawns and common misconceptions
With all the timely rains we have been getting this year, lawns are really growing and staying green. Many years our lawns slow down with hot and drier weather.
The University of Minnesota recently shared information about lawns and common misconceptions concerning them. This is a good time to share the information from Extension Turf Researcher Jon Trappe.
Collecting or bagging lawn clippings in a weedy lawn will cut down on weeds. The idea behind this is that by removing the clippings and weed seed heads, you will be reducing the number of weeds in your lawn for next year.
Research doesn’t support this practice as being effective.
If you have weeds in your lawn already, there is a strong chance there are thousands of other weed seeds already present in the soil. These seeds can be viable for years, so removing the lawn clippings and weed seed heads will likely not reduce the amount of weeds present. (I’ve heard that burdock seed can remain viable in the soil for 100 years.)
By removing the lawn clippings, you are removing up to 2 pounds nitrogen/100 ft. per year that the lawn would use to thicken and reduce weed pressure over time. A dense, healthy turf is the best defense against weeds.
Collecting or bagging lawn clippings will reduce the amount of thatch in your lawn. The thatch-mat layer that can build-up over time is made up of partially dead or decaying plant material containing lignin.
Turf leaves (which are what we are cutting when we mow) contain little lignin and are easily broken down by soil microbes over the span of a few weeks and do not significantly contribute to thatch.
If I mow the grass shorter, I won't have to mow as often.
While your mower may technically be capable of mowing your lawn from 6-8 inches down to 2 inches every two weeks, it is not recommended. Mowing more than one-third of the leaf blade in a single mowing event can damage the turf plants, making them prone to other stresses such as drought, heat, insects, or diseases.
By maintaining your lawn at a taller height, you will have a lawn that requires less watering, and is more heat, insect, and disease tolerant throughout the growing season.
Finally, by mowing according to the 1/3rd rule, you will also have to mow your lawn less frequently throughout the year.
If the lawn does get too tall for removing less than 1/3rd because of weather or other circumstances, consider mowing the lawn down in stages of mowings with a few days between for the lawn to recover.
Seeding a lawn
The best time to seed a new lawn in Minnesota is mid-August to mid-September. It is recommended to spread seed at a half rate in perpendicular directions across the site and this will aid in uniform distribution of the seed over the lawn.
Lightly rake, allowing about 10 to 15% of the seed to show. Use a roller over the area to ensure good seed-soil contact and water to a depth of 4 to 6 inches and follow with a light and frequent watering program. Of course you don’t need to water during rainfall events. After germination reduce the watering frequency as roots grow into the soil.
This spring I had to seed an area where I had some trees taken down and stumps ground out. I wasn’t very diligent in watering but Mother Nature helped me out and ended up with a good stand of grass. Occasionally dumb luck works!