Mowing & Trimming
The most basic of lawn care functions may seem easy but shouldn't be taken too lightly. If your grass is mowed too often, not often enough, too short, or with dull blades, the results can be devastating for the lawn.
How tall should the grass be?
Here in Colorado, the recommended minimum height for grass is 2.5 to 3 inches, according to the Colorado State University Extension. Mowing the grass down to 2" or below results in a decreased tolerance against drought and heat and can lead to a greater likelihood of weeds, diseases, and insects.
How often should I mow?
The lawn should be mowed often enough so that no more than 1/3 of the height of the grass is cut at a time. In other words, if the desired length is 3", the grass should be cut when it is no longer than 4.5". Depending upon a number of factors including species of grass, amount of rainwater and irrigation, time of year, etc., in order to maintain the recommended length of 2.5" to 3" the lawn may need to be cut as often as twice a week or as infrequently as every couple weeks.
If the grass has been allowed to grow beyond the 1/3 rule, the mower height should be raised to avoid cutting off too much at one time, then the grass can be cut again a few days later to the proper height.
Should I bag and compost my grass clippings?
Grass clippings decompose quickly and provide organic nutrients and ground cover for the lawn if they are mulched while mowing and allowed to drop back to the ground. They also help retain moisture in the soil.
There are some exceptions: if the lawn is particularly long and/or wet when mowed, resulting in clumps of grass clippings, it is best to bag or rake them up. Clumped clippings will result in lawn spots. Also, if you have a garden or other use for compost, use the bagging/composting method on alternate mowings.
A common misconception is that grass clippings contribute to thatch buildup and eventually prevent moisture from reaching the ground and roots. This is a myth--clippings decompose into the soil.
Should I mow shorter before Winter?
No. There's no reason to mow the grass shorter in the Fall or before Winter. Healthy grass will go dormant for Winter, so it is best to keep it as healthy as possible before the stress of cold sets in.