Soil pH is a test of how acidic or alkaline your soil rates. The pH scale has 14 divisions that range from 0 to 14 with 7 being the neutral point. This pH reading is similar to our ratings of heat and cold by using degrees. The pH condition of the soil will affect the quality of plant growth.
A near neutral or slightly acid soil which is between 6 and 7 is usually considered ideal for most plants. However, some plants prefer and need an acidic soil to grow well such as Blueberries. Other plants need a more alkaline soil.
The pH may vary by the area of the United States that you live in. Typically, the Southwest is hot and dry with a soil pH considered alkaline. Soil in the Southeast is acidic. However, in your own yard, the pH may vary in different areas of that yard. For example, soil at the base of your cement foundation may be more alkaline due to the lime leaching out of that cement.
The impact that extremes in pH have on growth of a plant is related to the availability of plant nutrients. In highly acid soils, aluminum and manganese can concentrate and become toxic to plant growth. At pH rates of 7 and above, phosphorus, iron, copper, zinc, boron and manganese become less available to your plants for their growth.
Signs of Alkalinity
One of the first signs of a plant that is growing in soil that is too alkaline is that the veins in the leaves will be green while the rest of the leaf is yellowing. A better way to determine the pH of the soil is through a pH test kit. For a small fee, your county extension office will send off your box of soil to be tested.
In about 2 weeks you will receive a letter telling you the pH level. If the soil pH is too acidic, the report will tell you how much lime to add to raise your pH. If your soil is too alkaline, the soil test will determine how much elemental sulfur or aluminum sulfate to lower the pH.
Organic matter is how to improve alkaline soil. Organic matter is the life of the soil. It may be added to the alkaline soil as compost. Compost is made from kitchen scraps, leaves, grass clippings, saw dust, shredded newspaper and such that are piled into a compost bin or simply in a pile at the back of the yard. This combination of greens (nitrogen) and browns (carbon) are allowed to rot. After about 1 year you have a sweet smelling, decomposed material called compost. Compost in the soil makes the soil become more acidic.
Another way to add compost to the soil is through worm castings. Red worms are kept in a bin. They eat kitchen scraps and produce frass which is compost. This process can be found on Google with sites devoted to the purchase of the worms and the bins in which they will live.
Another method to add compost to the soil is through the use of a mulch. Mulches maintain the temperature of the soil, reduce water loss and eventually break down into compost. Mulches can be bark mulch, chopped leaves, straw, pine straw or grass hay.
Planting a green manure is a process to add compost to your soil. They are planted in the fall and either dug into the soil in the spring to compost or simply cut or mowed down and left on top of the soil to be used as a mulch. Seeds of Red Clover, Alfalfa, soy, rye grass or wheat grass may be used as green manure. These plants will also reduce weeds in the garden.
Organic fertilizers may also be used. Chemical fertilizers are washed away quickly and may enter our water systems and pollute our streams. Organic fertilizers, in comparison, are released slowly to the plants and do not burn the tender growth.
To maintain alkaline soil improvement, compost, mulch and green manure must be constantly cycled into the soil.