Definition - What does Acidic mean?
In horticulture, the term acidic most often refers to a nutrient solution or growing media that has a pH well below 7.
An acidic environment occurs when a substance falls below 7 on the pH scale – the unit of measure for acidic versus alkaline substances.
Acidic is often used to describe soil conditions in traditional horticulture, but the term has its place in hydroponic gardening as well.
The opposite of an acidic environment is an alkaline environment. Products like pH Up and pH Down can be used to help with acidic environments.
MaximumYield explains Acidic
The pH scale is a numeric system ranging between 0 and 14 used to test acidity or alkalinity, with a measurement of 7 being completely neutral.
To most gardeners, the acidity or alkalinity of soil is a primary concern. Certain plants like blueberries, for example, prefer a more acidic soil, whereas species such as roses do not. The pH of the soil, however, is easily altered using compounds like lime or sulfur.
Almost all vegetable plants prefer a neutral or alkaline soil; however, there are plants such holly, boxwood, or myrtle that thrive under more acidic conditions.
Nitrogen from fertilizers can increase the acidity, along with the addition of plant-based organic matter such as compost or leaves. Most often sulfur is used in order to lower the pH.
In hydroponic gardening, monitoring and adjusting the pH of the nutrient solution is of great concern and a lot of care is taken in doing so. The nutrient solution can become too nitrogen-rich, for example, which will lower the pH level to a more acidic state.
Because of the importance of balancing pH, it is recommended that all gardeners purchase an inexpensive pH kit from the hardware store. Digital pH meters or pens can also be used. Upon finding out that the growing environment is too acidic, adjustments can be made almost immediately.