When a lawn is left untended, the grass often grows to a height that makes routine maintenance impossible without causing significant damage. Cutting excessively tall grass in a single session places immense stress on the turf, potentially weakening its root system and inviting disease. The volume of clippings can also smother the healthy grass underneath, leading to yellowing and decay. To restore a severely overgrown lawn, a measured, multi-stage approach is required to protect both the grass plants and your mowing equipment.
Preparing the Lawn and Adjusting Your Equipment
Before the first pass, the area must be thoroughly inspected for safety and to protect the machine. Overgrown grass often conceals debris like toys, rocks, or large sticks that can be violently ejected by the blades, posing a hazard. Clearing all foreign objects prevents bent blades, a damaged mower deck, or serious personal injury.
Equipment preparation is equally important. The mower deck must be set to its highest available setting, maximizing the height of the initial cut. You should also verify that the fuel and oil levels are correct and that the blade is sharp. A dull blade will tear the long, thick grass instead of cleanly slicing it, leaving frayed tips that make the grass more susceptible to disease and browning.
The Multi-Step Mowing Technique
The fundamental principle for cutting overgrown grass is the “one-third rule”: never remove more than one-third of the grass blade’s total height in a single cut. This rule is particularly important for long grass because removing too much photosynthetic material forces the plant to pull energy from its root reserves, which can temporarily halt root growth and weaken the plant.
For the initial cut, set the mower to its highest setting, aiming only to remove the top layer of the grass canopy. If the grass is 10 inches tall, the first pass should bring it down to approximately 6.5 to 7 inches. This pass reduces the bulk and exposes the lower parts of the blade to light, encouraging the plant to begin photosynthesis at that lower level.
Move the mower at a slower speed than usual to prevent the engine from bogging down and allow the blades sufficient time to cut the dense material. If the grass is extremely thick, you may need to mow the area in two directions (e.g., a north-south pass followed by an east-west pass) to achieve a cleaner cut and better clipping dispersion.
After the first pass, allow the grass a recovery period, typically 1 to 3 days, before cutting it again. This waiting period allows the plant to heal from the stress and replenish its energy reserves. For the second pass, lower the deck height incrementally, removing no more than one-third of the remaining height. Repeat this gradual process until the lawn reaches its desired maintenance height.
Managing Clippings and Lawn Recovery
Cutting long grass generates a large volume of clippings, which must be managed carefully to avoid harming the recovering lawn. Long, heavy clippings left in thick clumps can mat down and suffocate the turf beneath, blocking sunlight and creating an environment favorable for fungal diseases.
For the first, heaviest cut, it is best to bag the clippings or rake them immediately after mowing to remove the bulk of the material. Once the grass is closer to its target height, you can switch to mulching, provided the clippings are short enough to filter down into the turf canopy and decompose quickly. Mulching returns valuable nutrients like nitrogen, phosphorus, and potassium back to the soil, acting as a natural, slow-release fertilizer.
Following the multi-stage mowing process, the lawn will be under stress and requires focused post-mowing care. A deep, light watering after the final cut will help the turf rehydrate and recover. Avoid applying a heavy-nitrogen fertilizer immediately, as a sudden surge of nutrients can force rapid top growth, further depleting the plant’s stored energy and stressing the weakened root system.