The soil to hold on to

Published March 15, 2015
Loamy soil / Photos by the writer
Loamy soil / Photos by the writer

Having examined and explained water issues in previous columns, it is time to move on to that other garden essential, which so many gardeners, both new and old, are in the bad habit of taking for granted — and that is soil.

The soil you have inherited may be, all depending in which region of the country you reside of course, primarily sandy, moram, loamy, clay, calcareous or saline with — and again this varies, with acceptably high or low pH values. Rarely is the soil of our homeland in absolutely prime planting condition and a frightening percentage of it is highly contaminated, purposefully or inadvertently, with toxic chemical residue from pesticides, herbicides, weedicides, etc, plus, from industrial / commercial waste which has leached into groundwater and through this, into the soil.

Knowing your soil and first understanding, then correcting imbalances, is of primary importance: assisting it back to natural health — then keeping it in prime, fertile balance, is the very base of successful, productive, organic gardening.

Identifying your soil type is, once you know how, an easy matter, and ensuring its health and well being is not difficult but — these are essential ingredients which far too many gardeners lack — hard work, forward planning and a massive amount of enduring patience are required.

Identifying soil types and basic correction methods:

Sandy: Generally speaking, this has an extremely high volume — often over 85 per cent of clearly separate ‘grains’ which do not retain water. It is deficient in the nutrients / minerals that are essential for healthy plant growth but is easily improved and made surprisingly fertile by the copious addition of organic compost, old, well rotted, organic manure and clay: All of which, as well as being nutrient / mineral rich, are water retentive.

Moram: This is the sub-soil, lying at least three to four feet below the soil surface. Often comprising very dense, extremely heavy clay, it is brought to the surface where, for example, excavation — such as for housing foundation, the laying of pipelines, etc. — has taken place. Sub-soil is, no matter how treated, useless for plant growth as it sets so hard, especially during dry weather, that plant roots are unable to penetrate it. It is often a major problem in and around housing sites. If this is, unfortunately, what you have, the only workable solution is to construct what are known as ‘raised beds’, filled with ‘sweet earth’, river sand / compost / manure, in which all manner of plants will flourish.


Read on to learn what only a few gardeners know — the various types of soil and how useful they are for plants


Loamy: Wonderful soil! A reasonably balanced mix of sand and clay, containing lots of nutrients / minerals such as natural lime, which is water retentive. If it is slightly heavy on river sand, it is known as ‘Sandy loam’; if it has more clay, then it is ‘Clay loam’ and is easy to re-balance with the addition of compost / manure.

Clay: Clay soil is heavy, to the point of setting like concrete in periods of dry weather or after rain when it first has the viscosity of lethally sticky mud before turning into concrete. No attempt should be made to work clay soil when it is either too dry or too wet as this can result in serious damage to overall soil structure which then needs long-term, organic inputs to encourage repair. Clay soil, when re-balanced by the addition of lots of river sand (sea sand contains too much salt), organic compost / manure, can be transformed into highly fertile soil as it contains — locked away in its molecules waiting to be released by sand / compost / manure — a surprisingly high percentage of essential plant nutrients and minerals. However, even when re-balanced on a regular — at least seasonal — basis, it may remain prone to water-logging during rain / monsoon, so adequate drainage must be an integral part of garden design.

Calcareous: This is clay soil with natural carbonates of lime and / or natural chalk content. Very variable in productivity levels, it tends to be on the heavy side unless it also contains lots of small stones to aid drainage. Gravel soils also fall into this category and are often unsuitable for general plant cultivation but ‘specialist’ species, such as grape vines and rockery plants, may thrive. The addition of large amounts of ‘sweet earth’, plus, compost / manure, can render gravel soils suitable for general plants, fruit, vegetables and herbs although it may be preferable, certainly faster, to lay these additions on top of gravel soil, without mixing them in, and cultivate flowers / crops directly in this.

Saline: Soil salinity (salt) can be a major issue in coastal areas, including Karachi, and in an increasing number of localities throughout Sindh and Punjab. Some plants will tolerate a certain degree of salinity but many do not. In such places it may be better to build raised beds, filled with ‘sweet earth’, river sand / compost / manure laid on top of a six-inch deep bottom layer of either small stones or crushed charcoal: both of which slow down, but do not prevent, salinity from creeping up towards the soil surface, which it achieves through capillary action.

Re-balanced clay soil is plant friendly / Photos by the writer
Re-balanced clay soil is plant friendly / Photos by the writer

Soil pH:

Soil is acidic or alkaline as determined by the presence of hydrogen ions or alkaline salts: All soil thus has what is chemically termed a ‘pH value’. A pH value of over seven means that soil is alkaline, less than seven and it is acidic. If a soil test reading is simply ‘pH’ without a number, the soil is neutral and suitable for the vast majority of plants. If soil is heavily alkaline or heavily acidic, it will need to be re-balanced accordingly.

Simple soil testing kits are available in the market.

Please continue sending your gardening queries to zahrahnasir@hotmail.com. Remember to include your location. The writer will not respond directly by email. Emails with attachments will not be opened.

Published in Dawn, Sunday Magazine, March 15th, 2015

On a mobile phone? Get the Dawn Mobile App: Apple Store | Google Play

Opinion

Editorial

Judiciary’s SOS
Updated 28 Mar, 2024

Judiciary’s SOS

The ball is now in CJP Isa’s court, and he will feel pressure to take action.
Data protection
28 Mar, 2024

Data protection

WHAT do we want? Data protection laws. When do we want them? Immediately. Without delay, if we are to prevent ...
Selling humans
28 Mar, 2024

Selling humans

HUMAN traders feed off economic distress; they peddle promises of a better life to the impoverished who, mired in...
New terror wave
Updated 27 Mar, 2024

New terror wave

The time has come for decisive government action against militancy.
Development costs
27 Mar, 2024

Development costs

A HEFTY escalation of 30pc in the cost of ongoing federal development schemes is one of the many decisions where the...
Aitchison controversy
Updated 27 Mar, 2024

Aitchison controversy

It is hoped that higher authorities realise that politics and nepotism have no place in schools.