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Extension Education Center
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WHAT ABOUT LIME?
What does pH stand for?
The abbreviation pH stands for potential hydrogen or the measure of acidity.
What is the pH scale?
7.0 is neutral, more than 7 is alkaline or basic and will NOT require lime, less than 7 is acid and
may require lime.
How does the pH regulate soil nutrients?
The pH acts as a bank teller for nutrient withdrawal. At pH 8.0, a plant cannot extract potassium,
nitrates, phosphates, iron, copper and manganese. These may be limited in availability even
above 7.0. At pH 4.5, plants cannot take up nitrates, magnesium, or phosphates and aluminum
comes out and about and is taken up—sometimes to the point of toxicity.
Does an improper pH waste fertilizer?
Yes!!! Improper pH wastes applied fertilizer because nutrients are tied up. Consider the
following:
pH 4.5 may mean 75% of your fertilizer is unavailable to plants
pH 5.0 may mean 54% unavailable
pH 5.5 may mean 33% of fertilizer unavailable
pH 6.0 may mean 20% unavailable
pH 7.0 may mean 0% of fertilizer wasted
What kinds of pH readings are typical on Long Island?
Our soils tend to be acid unless surrounded by concrete. Therefore they MAY need lime…or
may not, depending on how much concrete they are surrounded with.
What are the benefits of lime?
Lime reduces acidic conditions that limit the availability of some nutrients but increase toxicity
of others. Lime helps supply calcium and magnesium essential for plant growth depending on
the formulation you use. Lime can even help favor conditions for efficacy of certain herbicides;
and provide a suitable environment for organic materials to decompose. The decomposition
enhances soil structure which provided for better air and water exchange.
What are the different sources of lime and what are their benefits?
Ground dry lime (Dry). Limestone rock is crushed and ground and goes by the name of
Aglime, Agrilime, Ag stone, Ground Agricultural Limestone, and Lime. This is the most widely
used liming material and is easy to transport and apply. The calcium content ranges from 15 to
40% and magnesium content ranges from 0 to 15%.
-CALCITIC Limestone has less than 5% magnesium
