Master Gardener, Fred
Hoffman gives tips on how little or how much water your plants need. Over watering or under watering can kill plants and lawns, find
out how much is the right amount.
ARE YOUR PLANTS GETTING TOO MUCH OR TOO
Improper watering is the number one cause of plant failure. Knowing
how wet the soil is where the plant roots are hard at work can help
you determine your plants' health.
To determine the amount of water at the root level:
A day or two after watering, dig down eight inches with a trowel
or small shovel, near the dripline (outer canopy) of the plant.
Doing this in two or three spots would be more helpful. At that
depth, grab a handful of the soil. Squeeze that handful. If it is
muddy and watery, reduce your watering for plants that require regular
(but not frequent) irrigation. If it is so dry you cannot form a
clod in your hand (it turns to dust instead), increase your watering
(for those plants that require moderate amounts of water). If you
can form a dirt clod in your hand, yet break it apart with a little
effort that is probably the correct soil moisture for your plant.
Extended, infrequent, slowly applied irrigation
is the most efficient watering method. Soaker hoses or drip irrigation
systems work best. Here in the Central Valley, foothills, and Bay
Area, run them for 6-8 hours at a time, once a week, in the summer.This
is only a guideline to get you started.
Adjust that timing to your particular soil type
And, don't forget: add more drip emitters and
drip lines as the plant grows, especially for trees and shrubs.
Make sure to get water to the outer canopy of the plant (and beyond)
where the roots travel.
During the hottest months (June through September),
you may need to add
an inch and a half to two inches of water to your lawn each week,
divided into two applications.
To determine how much water your sprinklers are
putting out: place six to 10 flat-bottomed, same sized containers
(such as small glasses. tuna fish or cat food cans) around your
Put some in the greenest areas; put some in the
areas that are struggling.
Turn on your sprinklers for 15 minutes. Then,
measure the amount of water in each container.
There should not be more than a quarter-inch difference
among all the containers.
If there is, readjust or add to your sprinklers
to hit those areas that aren't getting as much water.
If, on average, you are getting a half-inch of
water per container, then you need to water your lawn thirty minutes,
twice a week, to put two inches of water on your lawn.
You may need to adjust this timing if you see
water streaming off the lawn.
In that case, reduce the amount of time the sprinklers are on at
any one time.
Then, add a second cycle a few hours later. It is best to water
with rising temperatures, which in the summer, is from about 4 a.m.
to noon. Earlier is better.