Often cutting height is a matter of personal preference. Typically, you should mow the grass when it is between three and five inches high. The proper cutting height range for a specific lawn will depend upon several factors, the type of grass, the amount of rainfall, the prevailing temperature, and the lawn’s overall condition.
Cutting Too Short
Cutting the grass too short causes weak, thin grass plants, which are easily damaged by dry periods and pests. Cutting too short is often more damaging than allowing the grass to be slightly higher. Letting grass grow a bit longer, especially when it is hot and dry, reduces heat build-up, preserves needed moisture and protects the grass from heat damage and other problems. However, allowing grass to grow too high can cause thin turf and additional problems. Cutting off too much at one time shocks the plant’s growth system and weakens the grass plants. A good rule of thumb is the 1/3 rule: to cut no more than one third of the grass height, and never more than 1 inch at a time.
The amount of grass you are able to cut in one pass is also effected by the type of mowing system you are using (for example, broadcasting with side discharge decks can process a much larger volume of grass than mulching does).
For extremely tall grass, set the cutting height at maximum for the first pass, and then reset it to the desired height and mow a second or third time.
Don’t cover the grass surface with a heavy layer of clippings, this isn’t healthy for the grass. Consider using a grass collection system and starting a compost pile.
As mentioned above, cutting height is a matter of personal preference. These tips are simply a guide to help you achieve the perfect cut for the look you want your lawn to have.