Soil is a living thing; a living medium. It is full of micro-organisms, nutrients and minerals along with air and water, and its entire composition determines the success or failure of the garden. It is not just an anchorage space for plants but also deserves care and attention from time to time.

Soil exists in various trophic levels, ie., there is a food chain sequence in the soil, and various organisms and natural elements exist at the different links in this chain of consumption. Vegetables in a vegetable garden are directly dependent on this ecological trophic level balance.

The best step to garden soil preparation is to first understand the soil. From there, the next step would be testing the soil, improving the soil structure and lastly, adding nutrients, if necessary. The right attitude towards soil preparation will not only enrich the first years’ produce, but will also have a positive impact on the produce of the following years

# 1. Understand the soil

a) Soil Layers

The soil is made up of three distinct layers, viz. the topsoil, subsoil and bedrock.

Top soil is the living part of the soil, very fertile and rich in organic matter, minerals, air and water. The bacteria in this layer convert minerals and organic matter into plant food. In chalky soil, this layer is approximately 5 cm deep, while in rich loamy soil it reaches to a depth of even 1 meter. The shallower the top soil, the less fertile it is. In the process of soil preparation, the top soil should never be buried under the subsoil.

The subsoil is the layer below the topsoil. It is lighter in color and lacks humus, water and air. During soil preparation, the subsoil should never be raised above the topsoil.

Bedrock is the parent material of the soil present in a particular patch of land, is below the subsoil, and is made up of larger soil material like stones and rocks. It is mainly a mineral base.

b) Soil components:

There are four basic soil components, viz., Organic matter, minerals, air and water.

* Organic Matter:

Organic matter are living organisms, dead organic matter and humus. The living organisms may be microscopic like eelworms, bacteria and fungi, while the macro-organisms may be insects, earthworms, etc. The most common macro-organism to be found living in garden soil is the mole.

Dead organic matter are materials or remains from once-upon-a-time living things in the soil. Examples are dead roots, leaves, insects, twigs, etc. It serves as a base for humus formation and bacterial activity. Totally decomposed dead organic matter results in humus.

Plant and animal remains decomposed in the soil with a horde of living and dead bacteria form the humus. Bacteria and other micro-organisms are responsible for this decay. Humus may be described as a dark, jelly-like substance that binds mineral particles together into what is known as crumbs. Crumb soil in a loamy texture is considered to be the most fertile soil for plants.

* Minerals:

Minerals form the non-living skeleton of the soil which is derived from the weathering of rocks. The parent rock (present in the Bedrock) determines the fertility and size of the mineral particles. Based on particle size, particle names may be sand, silt, clay, stones and gravel.

Sand: Coarse / Medium / Fine

Coarse sand is 0.6 to 2.0 mm in diameter and is distinctively gritty.

Medium sand is 0.2 to 0.6 mm in diameter and is less gritty than coarse sand, with a table salt-like size comparison.

Fine sand is 0.02 to 0.2 mm in diameter and has hardly any gritty feeling.

Silt: Minerals with a silky or soapy feel and with a size of 0.02 to 0.002 mm diameter.

Clay: less than 0.002 mm diameter and is peculiarly sticky.

Stones and gravel have a size larger than 2 mm diameter with stones being sizable pieces of rock and gravel the smaller weathered bits and fragments.

* Air:

Air is part of the main life support and is required for the breakdown of organic matter. The process results in the release of nutrients into the soil. Air movement within the soil is a means of ventilation and release of toxic gas buildup in the soil. Movement of air is through the air pores.

* Water / Soil water:

Soil water is basically a water based solution which is rich in dissolved organic and inorganic materials. Nitrates, potash and phosphates are apt examples of plant nutrients found in soil water.

# 2. Test the soil

It is very important to know your soil and its nutrient or fertility levels in order to raise vegetables or any plant for that matter. Two essential tests like the walk over test and the hand test are ample enough for any gardener as it gives a fairly picturesque description of the soil fertility and approximate pH values. To add to the benefits, these two tests are practical, take only a few minutes to conduct and totally free of cost.

The walk over test is done by the gardener simply walking along the patch of land and observing the garden fauna and soil texture. If there are 30 or more stones per sq. meter, the soil is Stony. If the soil is not stony, but is rich in crumb, and is dark brown or grey in color, then the soil is peaty. If the surface is covered with moss or green slime then the soil has poor drainage.

Identification of plants helps to determine the pH distinctions; whether the soil is acidic or basic. The presence of Rhododendron, Azalea, Heather, Camellia and weeds like thistle, daisy or creeping buttercup are clear indications of acidic soil. If plants like okra, yam, and peppers are able to grow in the soil, then the soil is alkaline. When acidic soil plants like Rhododendron and Azalea show the presence of yellow leaves, it is a clear indication that the soil has turned alkaline or is predominantly alkaline.

The ability of vegetables to grow in certain soil types is also an approximate indication of the pH value of the soil Yam and okra grow in a soil that has a pH value ranging from 6.0 to 8.0, while cabbage grows in acidic soil with a pH range of 5.6 to 6.6. More about this identification may be seen in "How to test soil pH"

The hand test is done by simply taking a handful of soil and feeling the texture and particle size. Soil that is full of crumbs and rich in organic matter is loamy soil. Loamy soil may be sandy loam, clay loam, silt loam, etc based on the mineral particle size. If it is not loamy soil it may be identified as sand when it is gritty and it is not possible to roll the soil into a ball or clay when it is excessively sticky (when wet) and not gritty in feel and devoid of crumbs.

Pit Tests and Soil Tests using Soil Test Kits are the expensive versions of the tests and are done for more accurate readings.

# 3. Improve the soil structure

After the identification and evaluation of soil types and pH, conversion from one type of soil to another may be done, if necessary. However, the topsoil should never be mixed with the subsoil, and corrections may be made with the addition of humus or compost.

Procedures in improving the structure: This may be done by the process of tilling or digging bearing in mind that tilling should be done only once annually and done well. Tilling the wrong time may harm the soil, tilling too often will cause a disturbance in the ecological trophic levels, and tilling the wrong way may harm a person. Therefore is important to know the basics of garden soil tilling. Add humus or compost during the tilling process and leave it to set so that the microorganisms work on the decaying organic matter releasing essential nutrients. Disturb this balance, and essential macro-organisms like earthworms lose their place in the soil ecology rendering an imbalance to the soil community.

The best way to improve soil structure is by tilling once annually and then mulch, mulch and mulch even more to make the soil rich. The idea of tilling is to disturb the plant borne pathogens and unwanted soil contents like old roots and tubers from the previous crop that may hinder the growth of the next.

# 4. Add nutrients and fertilizers, if necessary

Once the soil quality is determined and drawbacks identified, the soil fertility may be corrected by the addition of fertilizers, preferably organic fertilizers, to the soil. Fertilizers are of three types, viz., organic, mineral and chemical. The choice of fertilizer should be determined by one who has a clear understanding about the quantity, plant type and application procedures of the fertilizer.

One very important point to note with preparing a garden for raising vegetables, soil should be properly ventilated and should have proper drainage for water. The best way to combat this issue is by building raised beds in row formation for planting the vegetables.

For most plants, the best time to prepare, till the garden and get it ready for a good crop harvest is the late autumn months, where the soil may set well during winter, rendering the soil fertile and ready for the final step; planting.

Article originally posted at

Guide to vegetable garden soil preparation

Learn more about this author, Amanda Dcosta.