"Sometimes that's all that's needed, provided the roots haven't been destroyed," says Brown. "However, if you don't see new blades of grass emerging from these spots within a week or so, you can assume the roots are dead. It that case, it will be necessary to replace the grass."
Brown says spots smaller than your fist should fill in by themselves as surrounding grasses spread. That's assuming the lawn is healthy and growing vigorously. It will take much longer for this to happen in a heavily shaded area or in a lawn where grass is thin and weak.
Larger spots will fill with weeds before surrounding grasses have a chance to take over, says Brown. Therefore, they require more aggressive repairs if you want your lawn to look good.
"Dig these spots out, then add some soil from your garden to bring them level with the surrounding grass," says Brown. "Mix a very small amount of starter fertilizer into the soil, then sprinkle grass seeds on top and water the areas frequently. You can also use products meant specifically for patching the lawn. They contain grass seed and starter fertilizer in a brightly dyed mulch. Simply spread the material and keep it moist, following label directions."
To repair the front yard, you might even want to make your own sod patches, says Brown. Dig out the dead spots and replace them with chunks of sod you have dug from a less conspicuous part of your lawn. Then seed the areas where you removed the sod, and water both the newly seeded and the newly repaired areas frequently. Continue watering frequently until the sod takes and the new grass is growing where you took out the original chunks.
The University's Yard and Garden Clinic has experts to answer questions on lawn and plant care and gardening between 9 a.m. and 1 p.m. weekdays, at 624-4771. There is a $5 fee, which can be billed to a major credit card.
Source: University of Minnesota Extension Service