Q. I need to ask your opinion about rolling the lawn. I have been told by neighbors that it does no harm to the lawn. I have seen on some Internet sites that it can hurt the lawn. Who is correct?
A. It depends on how heavy the lawn roller is and the type of soil one is rolling on whether any damage occurs to the lawn.
Most people roll lawns in the spring to flatten out any bumps that may have appeared in the lawn due to the shrinking and expansion of our clay soils and also because of the activity of earthworms and moles.
Once again, we have situations where folks overdo it when it comes to rolling a lawn. I have personally seen lawn rollers so large that they appear to have been once used to flatten out asphalt on a highway.
My advice on lawn rolling is to only use rollers that can be filled with water. Only half-fill the roller and use it when the soil is moist – not wet. If your lawn just has but a few minor bumps and valleys, my advice is to accept the minor imperfections and move on as you will do more damage than good by rolling the lawn.
The issue here is our clay soils. Clay particles are very small and will compact when pressure from a lawn roller is applied. Too much pressure and the soil becomes compacted. Turf roots have a tough time growing in compacted soils, and water will run off the compacted soil surface rather than penetrating into the soil.
When soil is wet, it is even easier to compact the clay. Never roll a lawn if you can take a bit of soil and squeeze water out of it.
Everyone needs to rethink lawn rolling and ask themselves – is it worth it to massively roll a lawn just to make mowing easier? Doing so makes the turf grass less healthy, and results in yet more runoff of water from lawns and landscapes into our rivers. This water isnt clean water; it is water that contains pesticides and fertilizer that ends up in our rivers and lakes. In a way, heavy lawn rolling is counterproductive. You end up watering more because the lawn wont absorb water, and more fertilizer and pesticides end up in our rivers and lakes.
Compacted soils will also be more prone to thatch buildup. This buildup occurs because the clippings and debris in the lawn have no place to dissolve into the soil, because it cannot penetrate the compacted surface.
Most gardeners would never dream of tilling a wet garden soil in the spring, because gardeners know this practice ruins the soil structure. For the same reason, one should never use a heavy roller on the lawn – especially if the soil is wet.