The grass is always greener… when you treat your finicky lawn right. But beware, the right way isn't exactly the intuitive way (just letting it grow probably isn't the smart move). The gardening and landscaping experts at Stack Exchange offer tips on keeping your lawn healthy and handsome.
During the warm months when my grass is growing, is there a mowing schedule I can use to encourage the lawn to be green and healthy? Mine often seems "unhappy" when it's been cut (goes pale, some browning), which makes me want to mow it less-often. Is there anything I can check to know when it's best to cut the grass?
It's a Matter of Length (Answered by JSBձոգչ)
It doesn't matter so much how often you mow, as much as how long the grass is. If your lawn looks yellow and dried out after you've mowed it, you probably have the blade on your mower set too low. Some people like a super-short lawn like a putting green, but doing this requires both a specific variety of grass and lots of extra care spent on fertilizing and other upkeep. Since you're probably not one of those people, your grass will be healthiest if you let it grow a little longer.
The first time I mow my lawn in the spring, I mow it on the longest setting. Subsequently I'll mow about every 1-2 weeks, depending on how much rain we've gotten (I don't ever water the lawn—we get plenty of rain where I live), moving the blade a little lower until it's on about the middle setting. Recently I've noticed that my lawn is looking a little yellow in patches, so I'm going to let it grow a little longer, then move the blade back up. If your lawn is in a similar state, you'd probably benefit from doing the same. Conveniently, somewhat longer grass is also more comfortable to walk on barefoot.
Mow Often… Conditionally (Answered by NickC)
There are several things that suggest the answer to your question is "the more often the better" and that your reaction to mow less frequently because of the yellowing you see after is the opposite to what you want for a green lawn.
First of all, we all know that for a lawn to be green it must be growing. Grass pales and turns yellow over time unless it's growing. Second, the key factor to keeping a growing lawn healthy is mowing it according to its growth. Therefore, if you get it growing quickly (fertilizer, lots of rain, etc.) then you simply need to be mowing more often. The faster the growing, the more mowing is needed, but the greener the lawn.
Most advice for a healthy lawn says to follow the "one-third rule": Never cut more than one-third of the height. If your grass is growing, you’ll be mowing. Each grass type looks best and stays healthiest at a certain height. Use your mower to maintain that height as closely as possible. Cutting your lawn too short can be just as damaging as letting it grow too tall. The basic rule of mowing is to never cut more than one-third of the leaf blade. Generally, this means mowing about once a week. In other words, it's true that mowing can be unhealthy for the lawn, especially if the lawn was cut too short within too short of a time period. In other words, you want to be consistent about mowing, and if you get it too long, you should only cut off 1/3 the next mowing and then gradually reduce the height.
Another factor in this equation is the optimal height for your type of lawn. Mowing for Dummies has a good table for this (and also echoes the one-third rule). So, when you decide to mow less frequently because of the yellowing you see, you're actually perpetuating the problem. Grass is greenest at the top of the blade, and when you let that grow longer than it should, you cut off the healthiest part. In other words, it's not the act of mowing that hurts it, it's cutting too much of the blades. Mowing the next day shouldn't hurt at all—as long as the blade is sharp.
There are a few other reasons that mowing as often as possible is the healthiest for your lawn:
Ever seen a golf course's lawn? They do use different types of grass than most residences, but the mowers are usually out every day. They cut a tiny bit at a time, and the grass always stays healthy. (Of course they are growing it quickly with lots of fertilizer and watering.)
Mulching is well known as a means to help improve the health of your lawn. The point of mulching is to turn what you clip into tiny shreds that simply fall back into the lawn. Many lawn mowers can do basic mulching if you remove the bag and apply a mulcher. Cutting more often gives you a higher chance of returning small pieces to your lawn, instead of long pieces which may not be good for your lawn.
I'm still looking for the reference, but I once read that "the secret" to a healthy lawn is "mowing twice a week."
Another piece of advice I received from a lawn care center was "Mulch twice, bag once." You won't want to be mulching long grass (as above) so you'll need to be mowing often to follow that schedule.
Keep in Mind (Answered by Peter DeWeese)
JSBangs is right on about not over-cutting. Some other important considerations are:
Keep your blades sharp to prevent any tearing whatsoever. Put away the string trimmer when your lawn is having problems.
Get a testing kit to check the fertility and pH of your lawn area and correct if needed.
Keep the grass long enough to shade the roots in hot months.
Encourage deep roots by watering deep and less often if you do need to irrigate.
Prevent stressors such as weed competition and grubs.
Again: The 1/3 Rule (Answered by msemack)
I found a few university studies that showed the healthiest height for most types of grass is about 3-inches. Depending on where you live, though, this may not be practical. Some towns and HOAs have a grass height restriction that is somewhat lower. The other thing I've found from multiple sources is that you don't want to remove more that 1/3 of the height of your grass in a single cutting. If you chop off too much at once, it stresses the grass. (This may be your problem.)
If your lawn is really tall, and you need to get it down to the desired height, you may need to do multiple mowings, removing 1/3 of the grass each time. (Wait a few days between each mowing.) So, if you're targeting a 3-inch grass height, you should mow whenever your lawn reaches 4.5-inches. As to how often you should mow to achieve that, it will depend on how fast your lawn grows.
One other thing to consider: If you have a huge riding mower, the tires will also be rough on the lawn. So, if you have to mow very often (once a week or more), you may end up harming the lawn. In that case, you may need to deviate from the above guidelines a bit.
Disagree with the answers above? Have your own expertise to contribute? Check out the original post, and see more questions like this at Gardening & Landscaping Stack Exchange. And of course, feel free to ask your own question.