Q.
Please explain the 40-30-20-10 rule when watering. Why is it important? There
are lots of different ways to water plants.
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| Doesnt matter how deep the roots are, all roots generally use water following the 40-30-20-10 rule. Divide the roots into four equal parts. The top fourth of the roots uses 40% of the water, the second quarter uses 30%, 20% and 10% follow suit. Drawing citation lost. |
A.
Most plants use water stored in the soil following the 40-30-20-10 rule. Divide
the roots of plants into four equal parts. If it is a large tree and its roots
are three feet deep, divide this three feet into four equal parts (nine
inches for each part). If one-foot-tall plant roots are one foot deep, divide
the roots into four equal parts (3 inches for each part).
After a heavy rain or a full irrigation,
plant roots start using the water stored in the top quarter (25%) first. When
this top layer starts getting used, then the plant begins using the second (25
to 50%) layer of stored water, then the third and finally the fourth. When the
plant finishes using water stored in the soil, it uses this water following a
40% (top)-30%-20%-10% (bottom) rule. Plant roots, just like the top, grow when
they use water. This is one reason plant roots grow deeper when they are
watered deeper.