If the plants in your lawn or garden aren’t doing so well, don’t be too quick to blame it on some horrible plant disease. There’s a good chance your plant troubles are the result of a pH imbalance, a problem that is relatively easy to diagnose and simple to fix.
What is pH?
The pH scale is used to measure the acidity or alkalinity of various substances, including soil. The scale runs from 0 to 14, with a pH of 7 being neutral. Anything below 7 is acidic, while anything above is alkaline. Soils typically have a pH somewhere between 3 and 10.
What Factors Determine pH?
A number of factors contribute to the pH in your garden, including the soil’s parent material and the amount of organic matter present. In general, however, pH is largely determined by climate conditions, especially rainfall. Areas with lots of rain tend to have more acidic soils, while dry, arid areas usually lean more toward the alkaline side of the pH scale.
What’s the Best pH For My Garden?
The ideal pH depends entirely on what you intend to grow. The pH of your soil is important for plants because it affects the availability of various nutrients, but each plant has its own specific preference. As a general rule, most lawn and garden plants prefer soil that is neutral to slightly acidic, with an ideal pH somewhere around 6.5. There are a variety of exceptions, of course. Many plants (such as pin oak, azaleas and blueberries) prefer acidic soils, while others (like olives, oleander and pomegranates) do best under alkaline conditions.
How Do I Determine My Soil’s pH?
If you don’t know the pH in your garden, the best way to find out is to have the soil tested. Soil test kits are available at most garden supply stores, and you can also have a professional soil test conducted through your nearest university extension office. The results of the soil test should tell you your soil’s pH and nutrient content, as well as making recommendations for possible soil amendments.
How Do I Alter pH?
Once you know the pH of your soil, the simplest course is to choose plants that are well suited to the conditions in your back yard. If you prefer to attempt to alter your soil’s pH, however, you have a variety of options.
- To raise pH, the most common amendment is lime, usually in the form of ground or powdered agricultural limestone.
- To lower pH, you can incorporate sulfur into your soil, either in the form of pure elemental sulfur, or a compound like ferrous sulfate or aluminum sulfate.
In either case, the results of your soil test should be used as a guide to what amendments you use, and in what quantities.