GARDENING: THE IDEAL PH BALANCE
Q. What is the ideal soil pH for flowers and vegetables? Is the use of pH paper a suitable measurement of soil pH and how can soil pH be altered from alkaline to acidic and vice versa?
A. A soil pH between six and seven is ideal for most types of vegetable and from 5.5 to 7.5 for most popular flowers. There are exceptions of course, as some vegetables and flowers require specific soil pH outside the ordinary range. Garden lime — preferably organic — is used to reduce soil acidity and sulphur to bring alkaline soils into an acceptable pH range. In both cases, it is necessary to study information on the packets to know how much lime or sulphur should be applied and it varies depending on the existing pH. Litmus paper — presuming this is what is meant by ‘pH paper’ — will only indicate acidity or alkalinity as it does not give the actual pH value. It is better to invest in a soil testing kit or to take soil samples, from three different garden areas, to an agricultural laboratory for testing.
Q. I often see the words ‘regular supply of water’ in this column. Please kindly explain them.
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A. It means to maintain suitable soil moisture, as required by specific plants, without allowing the soil to dry out.
Q. I live in Karsaz, Karachi and our inside lawn is American grass while the outer green belt has fine Dhaka grass. The problem is that there are so many earthworms beneath the grass that the quality of soil has become very poor. If we step on the grass our feet sink in the soil as earthworms have excavated so much. We sprayed locally available insecticides but this made no difference. What can we do?
A. Wow! Most people here do not have the earthworms needed for basic soil health and, to be honest, I am amazed by what you report here. Having never heard of such an issue before and having now researched it deeply, I must ask if you are 100 percent certain that earthworms are the culprits. It is more common to discover that it is the larvae of other insects, some kinds of beetle for example, that are capable of such damage. Please recheck and get back to me. I am intrigued.