Different Types Of The Garden Soil

The most important factors in any garden are the aspect and the soil itself. There are several different types of soil, although they do approximate to four main types. 

Loamy Soil 

Loamy soil is the best of all soils for any type of garden, consisting of small grains of sand (silica) together with a large quantity of decaying humus (vegetable or animal matter). Ideal loam would come from a meadow which has been in cultivation for many years, and in a garden its depth should preferably be in excess of 18in (45cm). Such soil is often only associated with older properties, but if a building development has taken place on farmland it is possible to encounter this type of soil even on a new housing estate. Loam is the type of soil that you will need to obtain if you are going to buy topsoil, or if you are compounding a mixture for filling containers or as a base for a rockery.

Small quantities of loam can be made continually in the garden for compounding sowing and seed composts. Cut curves to a depth of 2in (5cm) and then stack them one on top of another, with the grass side face downwards so that it is touching the soil of the turf beneath. Allow the soil to remain until it is a homogeneous, friable mass. 

Light Sandy Soils 

Lighter, sandy soils lack the body provided by the moisture- and nutrient-retaining humus, and consequently they tend to dry out very quickly and become impoverished. The result of this is that many plants will not prosper on them and those plants that do grow are frequently stunted. In addition, they tend to be very cold soils - their light color reflects the sun's heat, whereas the dark, humus-laden soils absorb and retain much of the sun's energy. Sandy soils are often acidic and are ideal for heathers, rhododendrons and camellias, but even where these are grown it is best to include as much humus as is practical to aid the moisture, nutrient and heat retention.  

This can be done either by including peat, which in the quantities required could prove extremely expensive, or the composted leaves of deciduous trees. Large quantities of these can be gathered in the autumn free of charge and composted by storing for a year in a compost maker, or even on a simple heap, which can be turned every three months. After a year you will have good quality humus. (Note: You should never attempt to compost the leaves of conifers such as pine needles as these contain toxins which can adversely affect soil fertility.) 

It is unlikely that you will be able to provide sufficient humus material in one treatment; the provision of this material should be considered as an ongoing operation. One method of providing humus material is to mulch each year, with deciduous leaves or even lawn mowing. This not only facilitates the retention of moisture during the current season, but the humus will also gradually be worked into the soil, aided by the action of the worm population which it will help to build up. It is far better to compost the dead plant material before adding to the soil if this is practical. One of the problems with light soils is that they are deficient in nutrients. Simply adding artificial fertilizers will not solve the problem. Water-soluble chemicals will dissolve in the rainfall and, there being very little humus material, the nutrient-rich water will pass into the water table, and the minerals will be leached from the soil. 

Heavy Clay Soils 

Heavy clay soils are made up of minute particles of mineral material cemented together, and is often rich in plant nutrients. However, they have the disadvantage that the nutrients tend to be locked in and they need to be released with lime. This presents no problems at all for the vegetable grower, but the landscape gardener will probably wish to work with some subjects that are not lime-tolerant. The most practical way to deal with clay soils is to add extra humus materials.  

This has the advantage of opening up the soil. Clay soils are also very heavy to work, and it may be quite late in the spring before it is possible to get on to them to do any digging. It is advisable with all soils to complete the heavy digging in October before the worst of the weather sets in, and this is even more important with clay soils - not only are they far easier to work before they have become waterlogged, but the crystals of ice formed by the frost will tend to break up the soil into a fine tilth. 

Chalk Soils 

These are down land soils, with only a covering of loam, which yield good cereal and vegetable crops. Flowers and shrubs can also be grown successfully on them, but you will need to be aware of flowers which are not tolerant of chalk. Chalk soils tend to be well drained, but initial digging is extremely hard work.