pH is the potential Hydrogen ion value in any given substance. It is an indication of that substance being either in an acidic, neutral or basic state. Anything with the pH value 7 is considered neutral while those values less than 7 are acidic and those greater than 7 are basic or alkaline.

Just like anything else, soil too exists in any of these three states and their values determine the types of plants that can thrive in such soil. There are many ways to assess the pH of soil; conventional or observatory methods and the scientific method with the use of Soil Test kits.

Soil pH is basically the amount of lime present in the soil. Moist climate tends to favor acidic soil while alkaline soil is found to prevail most in dry climatic conditions.

Observatory methods:

This is the conventional method that most gardeners adopt to gauge their garden soil types by identifying the types of plants growing in a particular region

Scientific studies have estimated the approximate pH values of the soil that most vegetables (and plants as a whole) thrive in. For example, yam, okra, mushroom, peppers and parsley grow in soil that has a pH value ranging from 6.0 to 8.0. Hence, the presence of these plants in any given soil indicates an approximate soil pH value.

Peas, cabbage and artichoke indicate that the soil pH is approximately 5.6 to 6.6. Carrot, catnip, cucumber, chives, dill, eggplant, garlic and peanut are indicators of values 5.0 to 6.0. While soil pH values of 6.0 to 7.0 are indicated by the presence of plants like lettuce, mint, asparagus, beans, cauliflower, celery, chard and radish.

Among plants other than vegetables, weeds like dock, thistle, daisy, plantain, creeping buttercup, and shrubs like rhododendron, azalea, heather and camellia present in a given patch of soil are indicators of the soil being Acidic.

Alkaline soil helps weeds like clover thrive. It also reflects in the above mentioned shrubs (rhododendron, azalea and camellia) by the presence of unhealthy yellow leaves.

Scientific method; Soil test kit

The more accurate method for determining the soil pH value is by doing the Soil test. This is by using the many available, scientifically approved kits which give point by point readings, rather than an approximation of values.

The soil test kits are used for testing the potash and potassium content of the soil along with the pH. Therefore it goes hand in hand with testing soil pH on a scientific level. There are many kinds of kits. Some involve indoor testing methods with the use of test tubes and solutions while others are by probes inserted into the ground. These tests indicate lime absence or deficiency in the soil.

To raise the soil pH towards a more alkaline concentration from acidic, nutrients like crushed marble, crushed oyster shells, bone meal or hardwood ash may be added to the soil. Sawdust, woodchips, cotton-seed meal, compost and peat moss help make soil acidic.

Article originally posted at

Vegetable Gardening: How to test soil pH

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