This [unedited] guest post is by a student in my EEP100 class (background post).
Please praise/critique/comment on its economic quality and importance to you.
Gilberto Villicana says:Why is it better to water your lawn early in the morning or at night versus doing it in the middle of the day? I have always walked around campus and asked myself when do all the plants and lawns get watered. I have to go to work at seven in the morning at times and find the grass wet, but I always used to think that it was due to mist or fog. Not knowing when the lawns were watered made me believe that it was done at night.
The reason that it is done at night is because there is no sun to dry up the water. What that does is allow the water to penetrate farther into the dirt reaching the roots of the grass better. This allows the grass to absorb more water, which makes it look better by being nice and green. It also has to do with the amount of water that would be used.
If we were to water the lawns in the middle of the day, the sun would dry up some of the water and not allow it to penetrate the dirt as much. Due to the sun, it would be more costly to water during the day because a lot more water would be needed in order to get the same results as if we were to water the lawns at night. There are also social benefits to watering the lawns at night because people actually go read or eat on the lawns. If the sprinklers were on during the day, people would not be able to sit on the grass because it would be wet.
Bottom line: It is less costly to water lawns at night and also allows people to sit outside and enjoy the nice weather.
3 comments:
There is more to this story.
In places with low humidity and sprinklers for watering during the day only 50% of the water emitted by the sprinkler gets to the ground. The rest evaporates.
In places with high humidity, watering at the wrong time at night does not allow the leaves to dry off so the plant gets fungus or mold on the leaves and dies.
The economics are different for drip irrigation systems.
Watering at night certainly causes the dampness/mold issue. The best time to water the lawns is early in the morning, just before sunrise. It allows penetration of water to the roots, at the same time doesn't dampen the grass/plants too much and the remaining water dries out soon leaving dry grass for people to sit on.
Not having lawns that need frequent and heavy watering saves a lot more water!
Timothy
www.friendsofwater.com
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