When to mow the grass? If you’re me, the answer is always, “tomorrow.” If you’re my neighbor, the answer is always, “Sunday at 8 a.m.” For the most part, I mow the grass when it is convenient for me or, as of late, whenever it stops raining long enough to get outside and do it. However, it got me to thinking; When is the best time to mow that is actually the most convenient (and healthy) for my lawn?
In terms of time of day, the consensus is that mowing should be done in the late afternoon/early evening, and I’m not just making that up to say, “I told you so” to my neighbor. Early mowing is bad for a number of reasons: For starters, usually the ground is wet in the morning. You should always try to avoid mowing a wet lawn as it will result in uneven mowing, clumping of wet grass on your lawn, and is bad for your mowing deck. It also speeds up evaporation — when you mow, you are exposing more of the ground to the elements by removing the thicker foliage from the grass that shades the newer shoots and root system. This exposure results in a loss of moisture, which can negatively affect your grass as moisture helps in the rejuvenating process. Grass usually needs 1-2 days to recover from the shock of mowing and moisture is key to getting that process started. Mowing early in the morning means you are exposing that grass to a full day of heat and sun, which is not good for a recovering plant. Remember, anytime you negatively affect the ability for your grass to grow, you are giving weeds an opportunity to do so. Mowing in the late afternoon when the grass is dry gives your lawn a solid 12 hours or so to recover when the sun is down and the evaporation of ground moisture isn’t an issue.
The other thing that you want to take into consideration is the length of your grass. Most people make the mistake of keeping their lawn clipped way too short. Generally speaking, the optimal length of your grass should be kept at 2 ½ to 3 ½ inches. Again, this is primarily a moisture issue. You want to keep the grass longer to create shade on the ground to retain moisture — it drastically reduces the need for watering. It also helps to prevent weed growth by keeping the lawn long enough to shade them out.
Remember, you never want to cut more than a 1/3 of the length of your lawn at any given time. This rule is true for most any plant and applies to pruning as well. Cutting off too much growth reduces the plants ability to photosynthesize because you are removing its food factory — the foliage. It also deposits much more thatch as you mow, essentially mulching your lawn. If you have let your lawn get too long cut off a third and then go back in a few days and cut it back further. I know it seems like more work, but in the long run, your lawn will thank you.