The heat and dry weather in June have turned many lawns (or portions of lawns) brown. With July and August being traditionally hot, brown lawns may persist.
What is the brown? The brown is most likely dormant turf or leaf blight.
Dormancy is a natural, protective mechanism for plants. In dormancy, plants stop photosynthesizing to conserve water, nutrients, and energy. A dormant state helps the plant survive bad growing conditions. During the summer, grass can enter dormancy due to heat or lack of water.
Leaf blight is a disease that attacks the leaf of the grass plant causing it to turn brown. Leaf blight resembles heat stress; however, symptoms can appear rapidly. Leaf blight can occur sporadically in a lawn. Shaded areas are usually less affected. Leaf blight normally occurs during high temperatures and can occur even if the lawn is being watered.
Neither dormancy, nor leaf blight, will kill the grass. The latest turf research says that reducing traffic (such as mowing and playing) and maintaining adequate levels of fertilizer are the best ways ensure good recovery when cooler temperatures and precipitation occur. Much like coming out of winter, a brown lawn will take a few weeks to start growing and turn green.
What can you do now?
- Continue to maintain higher mowing heights and mow as infrequently as possible. We recommend 3.5 inches at this time.
- You want your lawn to recover more quickly. Make sure your lawn gets regular water every other day. Once the lawn has recovered, you can return to a deeper and less frequent watering program.
- You are okay with the brown. Make sure your lawn gets some water every 10-14 days. Regular irrigation isn’t needed but going too long can be detrimental to recovery.
If a lawn does not fully recover, overseeding can help repair the bare/thin spots. August and September are the best times to overseed in the Twin Cities, so depending on the quality of your lawn and your expectations of the lawn, you may want to consider overseeding this fall.