Q. I’ve checked the internet and have some information from our state, but I still can’t compare the terms “infrequent” and “moderate”.
Does “infrequent” mean once every two weeks?
Once a month? And what does “moderate” mean? 1 gallon per watering?
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| Root depth of plants has to do with their size, genetics and the kind of soil. The deepest roots are with large trees, from an arid climate and growing in a sandy soil. |
A. I agree those terms are misleading. I think those
terms are used by people who don’t understand the differences themselves or
they would explain them. “Moderate” amounts of water refers to the amount of water a plant is given. “Infrequent” referst to the frequency of water or how often water is given. These are the two major concepts related to irrigation and are used to schedule any irrigation controller. It sounds like a topic for my audio podcast, Desert Horticulture.
Big Plants Need More Water
Two
concepts should be understood. Bigger plants have deeper roots. Deeper roots are encouraged with “infrequent” watering. This is about how often to give water. Plant roots
extract water from the soil deeper and deeper as the soil at the surface gets
drier and drier. The surface roots are the first to “suck up” water after an
irrigation. The roots take water from the soil deeper and deeper as the soil
gets progressively drier toward it’s surface. As we water plants
“infrequently”, the roots extract water and grow into deeper and deeper layers
of soil. Deep rooting of plants is the main reason good gardeners say, “Water
plants deeply but infrequently.”
Get Away from Daily “Small Sips” of Water
The
major reason we do not give plants “tiny sips of water” daily is because this
type of watering practice encourages plants to grow their roots more shallow.
There is a second reason; tolerance to heat. Plants with deeper roots have a
better chance of withstanding the heat of summer.
“Moderate”
amounts of water relates to the amount given to the plant. It usually means enough water to “wet the roots growing in the
soil” and little or no more. We learned that the depth of plant roots depends
on the size of the plant; bigger plants frequently have deeper roots than
smaller plants. The depth of plant roots also varies with the genetics of the
plant and the type of soil.
Water “Infrequently”
The
deepest roots are with those plants that are large, have the genetic potential
to grow deep roots and grow on sandy soils. The shallowest roots are found on
small plants that don’t have the genetic potential for deep roots and grow in a
heavy clay soil.
Correct. However, the first plant I ever tried to dig up (ca 1955) was a little creosote bush about four inches tall and wide. The single, 3/8" root (no branching) went straight down into the sand to three feet, where I gave up–I figured it must be a phreatophyte. I coiled the root into a gallon can, filled it with desert soil, watered it, added more soil so the thing wouldn't pop out like a Jack in the Box, put it in back, and drove over the washboard desert roads until the soil was packed hard against the root so tightly I couldn't get a pencil more than an inch into the surface. It lived a long time as a Bonsai.
How deep do you figure a Larrea root will go down?
Cacti and other succulent plants tend to have wide-spreading shallow root systems, even in sandy soils, apparently to capture the light rains and store it for dryer times.
Definitely a longer term learning process.