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On Mon, 3 May 2004 20:40:17 -0500, "RoyDMercer"
wrote:
Actually mowing higher will prevent some weed growth because the taller
grass will shade the soil which prevents weed seeds from germinating.
However keeping grass mowed shorter encourages deeper root growth and
thicker lawns, which prevents weeds also.

I have a warm season grass (Bermuda) I leave it tall in the fall and
throughout the winter and early spring (when the grass is dormant) and
weeds
are actively trying to germinate. Later in the spring when the grass
starts
to come out of dormancy, I gradually cut it lower each time until I reach
1
1/2 inches. I leave it short throughout the growing season for the
reasons
you mentioned. Proper mowing height is dependant on what type of grass
you
have. Hybrid Bermuda does well cut as short as 1/2", but some grass
varieties need to be as much as 3-4" to do well.

I prefer to use pre-emergent products to prevent weeds rather than
blanket
spraying for them. Whatever makes it past the pre-emergence, I spot
treat.

You are very correct about cutting no more than 1/3rd of the blade's
height.
I actually shoot for 1/4 of the blade's height. So right now I'm mowing
every 3-4 days. The shorter your grass is the more often you need to
mow.
Also, the shorter you mow your lawn, the less water it needs to stay
healthy.


The Shorter the mowing, less watering? I heard shorter the grass more
likely it will dry out. Can you explain?

I was referring to lawns mowed much higher than recommended. If you are
mowing so short that the soil is exposed, then yes, the soil will dry out
and you'll need to water more. However longer grass equates to a higher
Water Use Rate (WUR). The reason for this is because the higher the leaf
area, the more water will be lost to transpiration. This is why it's
important to mow at the proper height, for the lawn type you have. If the
lawn is mowed way too short, the soil can be exposed and water can be lost
to soil evaporation. If the lawn is mowed way too long, water will be lost
to excessive transpiration.

Quite a few horticultural publications and web sites recommend allowing
grass to grow longer to decrease irrigation rates. What many of them don't
tell you is letting the grass get too long has the reverse effect.