Understanding Soil PH Levels...
The degree of
acidity or alkalinity of the soil is called the soils PH level.
It is determined by the soils composition or the materials
that make up the soil and is measured on a scale of 0-14.With Acid being numbers ranging from 0-7 and Alkaline
being numbers ranging from 7-14.
Most soils fall near the middle of the scale between 4.5-8.5
and are considered to have a neutral PH Value, being neither overly acidic or overly alkaline.
Why Would We Care About Soil PH
Soil PH influences both the
chemical form of elements in the soil as well as soils microbial processes.
WHAT ARE YOU TALKING
I know I just went all
technical on you, sorry, let me explain.
Plants are affected by soil PH
because some of those elements in the soil are essential nutrients that the plant needs and uses to grow and
function properly. Others of those elements in the soils can be toxic to plants when present in excessive
Soil PH determines the amount of
the existing element that is in solution at any one time. Ooops did it again, beeeep… beeeep… beeeep…(that was
me backing up)
Ok, soil PH determines the
amount of the element in the soil that is available to be taken up by the plants root system at any one time.
me give you an example….
Palm trees in South Florida
often suffer from a micronutrient deficiency of manganese that causes a condition called “Frizzle Top” The palms
health suffers and the new leaves or fronds that form are weakened and smaller than normal etc. As the problem
gets worse new leaves will come out withered and looking scorched or “frizzled”.
This whole problem is due to the
simple fact that Manganese has a low soluability in South Florida’s high PH - Alkaline soils. It is not that
Manganese is not present in the soils in South Florida but that the PH being highly Alkaline will not allow much
of the existing manganese in the soil to be in an available form that the palm is able to take in through its
root system and use.
Better? Ok, whew, moving
Raising Soil PH
- Characteristic of heavy rainfall areas high
in sandy as well as humus soils.
- Help raise the PH of very Acidic soils by
adding lime in the form of agricultural limestone.
Lowering Soil PH
Alkaline or High PH
- Characteristic of light rainfall areas with soils high in lime like limestone marl or
seashells and sodium content. High Alkalinity can also result from concrete left over from construction of a new
home or mortar from a wall that was just built etc.
- Help this condition by adding organic matter compost or
cow manure, composted leaves, peat moss, ground pine bark or other wood chips, mushroom compost,earth worm
castings and elemental sulfur can be incorporated into the soil to help lower the PH.
I should note here that not all sulfur
compounds that increase sulfur levels will acidify the soil, so don’t use calcium sulfate(gypsum) or potassium
sulfate or magnesium sulfate(Epsom salt) to acidify the soil, you will be wasting time and money. You can use
some sulfate compounds such as ammonium sulfate aluminum sulfate or iron sulfate that do have some soil
acidifying results. All attempts to change soil PH will be temporary.
The clayey soils in North Florida tend
Tips for wading the preverbial waters of the PH scale.
- Concern about PH in a normal
landscape situation is almost always exaggerated…it must be just fun to write about. I’ve been blabbering on
unnecessarily for days!
Landscape plants are
more tolerant to PH than most of those little tags that come on plants would imply.
Lowering soil PH with
elemental sulfur will result in a lower PH for all of a three week period before it is used up and the soil
begins to return to its original value! Now that’s an uphill battle.
- Popular Florida lawn grasses
including St. Augustine, Bahia, Centipede and Bermuda are tolerant of Acidic soils commonly found in North
Now that you have conquered understanding soil PH levels; for other
common issues to the North Florida | Jacksonville | St. Augustine landscape, check out
Sod Q @ A page