The height that we mow our lawn is usually not given much thought. The mower is usually purchased and whatever it was set at from the factory is the height we mow our grass at. Taking a little time and adjusting the deck cutting height is an easy way to create a healthier lawn.
Benefits of Mowing High
- Taller grass is more capable of holding moisture in the soil, reducing supplemental watering needs. As grass blades grow, they shield the ground from the baking sun. They create their own "microclimate", similar to that of a tiny rainforest. This system can then allow water to be stored in the soil profile for longer periods of time. When it is cut down too short, all of these benefits disappear due to more soil being exposed to the heating and drying effects of the sun.
- Taller grass can smother out weeds easier. All seeds need 3 things to germinate (sprout): moisture, soil contact, and sunlight. Taller grass can more effectively block out sunlight from the soil surface, reducing the amount of weeds that even germinate. The ones that do have to compete very hard to get any sunlight through the taller canopy.
- Taller grass allows for a denser root system to develop. As grass grows, the amount of surface area that can photosynthesize is increased. This translates to a larger root mass, as that is where energy from photosynthesis is stored. With a greater root mass, the turf has access to more water and nutrients and it keeps the soil from compacting as much.
- Taller grass reduces soil compaction. Rainfall is on bare soil is one of the leading causes of soil compaction. By leaving more lawn on top of the soil, the grass is more capable of slowing down water droplets before reaching the soil surface. The water then easily absorbs into the soil versus hitting it and running off.
So How High Should I Mow?
Raising the cutting height to a minimum of 3.5" is imperative to getting some of these benefits. 4" shows to have the best results without losing the "clean lawn" look, but it doesn't look quite as crisp. Unless you live in an HOA that is very strict, we highly recommend 4".