Aerate regularly to loosen soil and allow more moisture and oxygen to reach the roots. Overseed to thicken lawns. Fertilize regularly using a nitrogen-rich fertilizer, such as Milorganite, to keep your grass lush and green. Stay on top of pest problems before they get out of control.
Herein, what causes your lawn to be bumpy?
Freezing and thawing of the soil during late winter and early spring also contributes to the roughness of lawns. The repeated freezing and thawing lifts up or “heaves” the soil, causing the soil surface to become rough or bumpy.
Put a thin layer over the problem area and spread it across evenly. Push the soil down to compact it with your feet or a flat side of a rake. Water the soil a little and leave it to settle. After a few days you can then add grass seed and another light layer of topsoil.>>>
Besides, can you put top soil over grass to level?
Using a dry topsoil and sand mix is much better for leveling uneven areas than putting sand on a lawn without mixing.