It's often necessary to make applications of agricultural limestone to raise
soil pH into a desirable range. However, some plants, such as Azaleas
and Rhododendrons, prefer an "acid" soil and don't respond
well to liming.
As a general
rule, most lawns
and garden plants prefer a soil that is almost "neutral" in the 6.5 to 7.2
from our soil
referred to as the "acidity" of the soil and is measured by
the number of Hydrogen ions present in the soil solution. Since
S.W. Pennsylvania receives considerable rainfall every year, and since
rain is H2O, soils tend to revert back to an "acid condition."
Ammonium fertilizers also have an acidifying effect on the soil.
When the soil
pH is too "acidic" (low pH) or "alkaline" (high pH),
nutrients present in the soil become locked-up or unavailable.
Correcting the pH has the same effect as applying fertilizer since it
"unlocks" plant nutrients already present.
Most plants grow best within a
pH range of 6.5 to 7.2 (7.0 is neutral).
The best way to find out what your soil needs is by sending a sample to
a soil lab. Donnan Landscape Services can provide soil test
results if you reside within our service area.
we've tested in the South Hills of Pittsburgh and Washington County
over the past 20 years usually need lime and phosphorus. The exception would be soils located in "bottom ground"
(near streams and rivers) which usually don't require lime. Of
those soils requiring lime, dolomitic lime (high in magnesium) usually
fits the test recommendations best.
speaking, the finer the particle size of lime the faster it will have an
affect on soil pH. Particle size is indicated on the label as what
percentage will pass through a certain "mesh" size.
Some lime products are powders that are turned into pellets for
ease of application and much less mess. We use and recommend this
form of lime.
while less expensive than pelletized products, can be very messy and
difficult to spread. Many have a "dusty" consistency like that of baking
are several types of lime available but we recommend only using the less
caustic agricultural forms of lime such as Dolomite Lime or Calcium
Carbonate. Remember that 'pelletized' products are much easier to apply.
The most commonly available and least expensive lime product is probably Calcium Carbonate
in the powder form.
In addition to containing Calcium, dolomitic lime also contains a
higher percentage of Magnesium than calcitic limestone. If calcium
and magnesium levels are low, use this type of lime.
and burned lime
Both types are
generally considered unsatisfactory for use on lawn areas. If used for
other applications, be sure to read and follow label instructions.
The CCE provides a yardstick for comparison of various lime
products. Limestone recommendations are based on a neutralizing action
equal to 100% calcium carbonate limestone. Use the formula below for
calculating the amount of lime to use:
CCE of Lime Material
moves very slowly down through the soil profile so it is best to mix
recommended amounts with the soil using a rototiller or similar device.
When applying lime to an established lawn, it is beneficial to apply
lime in conjunction with core aeration, using a machine that pulls out
General recommendations call for separating lime applications from
fertilizer applications by at least two weeks.
Even though fall is often prescribed as the ideal time of the year to
lime, due to the freezing and thawing action of soil over winter, lime
can actually be applied anytime of the year.
Always read and follow label directions!
Wood ashes raise soil pH