Three Reasons for Spots in a Lawn (Uhm, four)

Q. My hybrid Bermuda grass lawn from seed is coming along well but have this spot that is turning yellow.   Any thoughts?

Spots developing on a seeded hybrid bermudagrass lawn.

A. Do you have a female dog? The brown spots on the bottom of the picture look like dog spots from peeing. Brown spots from dog pee are usually greener at the edges of the spot and then get die in the center of spots that are about 8 to 10 inches across. But there is browning in the center of the picture as well.

Urine damage from dog

Checking for Insect Damage

Yellowing in spots can result from several possibilities. The possibilities are insects, watering or disease. Let’s eliminate one at a time and discover the most likely reason. The easiest to determine our insect problems. On the edge of the yellow area where there is a mixture of green grass and yellow grass pull on the grass like you are playing and pulling at someone’s hair and jerking their head back. Not rough but gently pulling. Most insect problems cause mechanical damage to the plant. When you pull on the grass and it has damage from insects, the grass comes up easily and to severed from the roots. You will get a mixture of green grass that looks fresh and dead grass in your hand. The insects that cause this damage are white grubs usually in the spring and side webworm in the summer. If this is the case and you find this true, then go to your favorite nursery or garden spot and by an insecticide to kill the grubs or side webworm. 

Not Insects?

Now let’s say the yellow spot is not insects. The next category we have to eliminate is disease. Most diseases when they are present will leave a few brown spots on the leaf blades and stems or dieback on leaves or spotting. When you are on your hands and knees checking for insect damage, also check the leaf blades in those areas for disease problems such as small brown spots. This is less likely than insect problems but if you think it might be a disease problem then go to your favorite nursery or garden center and by a fungicide for lawn diseases and make the application. Some lawn diseases can be spread from lawn to lawn by mowers.

Not Insects or Diseased?

The third reason can be irrigation, if you just started this lawn it went be too often and keeping the soil too wet most likely. Once the seed has germinated and the lawn is growing you should not be watering more than once a day. With Bermuda grass you might be able to water every other day even when it’s hot. The only way to know is to try and but definitely not more than once a day. Don’t water your grass again until you see any signs of water stress on the grass. 

Footprints when grasses like fescue need water

This is a smoky green color or when you walk across it it’s leaving your footprints in the grass. This tells you it’s time to water again. In the summertime when it’s hot you can’t fool around and wait a day to get the irrigation on. You must water it as soon as you see it when it’s hot. In cooler temperatures in the 80s you can go a day without watering and it won’t affect the lawn but not now.