The perfect soil does not exist and most gardeners have to make do with whatever nature or the house builder has left them. The soil itself ultimately governs which plants will grow well and anyone who doubts this should try to grow rhododendrons on chalk or lime. This plant and an alkaline soil are quite incompatible. Soils in Britain vary enormously between heavy clays and light sands. A child can tell the different between muddy clods of clay and dry sandy grains and these physical differences matter to the garden.



Clay is made up of tiny particles so small that they cling together and will not easily allow even water to pass between them. They have the same effect on a spade or the root of a plant. Sand, on the other hand, is made of comparatively enormous grains. They are so large that water washes easily through them and incidentally drains away a lot of nutritional material. They are so loose that sand will pour off a spade and give little support to a root system.

There is a definition of the two extremes and the particle size ranges between them but the gardener can usually tell at a glance or a prod. Science can tell the gardener the chemical constituents of a soil in minute detail but all that most people know whether soil is acid or alkaline. Some plants show a marked preference for one or the other so a simple testing kid from the garden store or centre can save the gardener a lot of frustrated efforts.

Testing is simply a matter of mixing a sample of soil with a chemical to obtain a colour code reading. Acidity or alkalinity is usually expressed as the Ph number. Seven is neutral. Any number down from seven is increasingly acidic and any number above seven is progressively alkaline. Most plants like the soil to be Ph6.5 that is just on the acid side of neutral.

Your Garden Soil Needs Food

The gardener calls it compost. It can be almost any organic matter and, except in Fenland-type soil where the earth is made of half-rotted vegetation, it will always benefit the garden. Thrown out kitchen vegetables (not root vegetables), horse or farmyard manure, straw, hope, or even woollen waste, together with the obvious greenery from the garden, will rot down to form compost.

It is the cheapest way of keeping a healthy fertile soil. Compost heaps will differ in construction and contents but they all need air and water, If they are too dry, waterlogged or airless, they do not rot or heat up enough to destroy the seeds of weeds or crops and may encourage disease.

Two or three square bins about forty inches wide are useful size for the average garden. One full for spreading, another rotting and the third being filled is an ideal routine. If the bins are made of wood, half inch gaps between each spank will ensure an air supply and a solid or polythene cover will stop the compost getting too wet. As each layer of refuse is dropped on to the heap a sprinkling of nitro-chalk or commercially produced rotting agent will help bacteria to break down the vegetation.

A light dusting of lime should be applied every few layers to prevent acid build-up which can prevent the complete breakdown of vegetation. Quick decay is helped by moisture and warmth, April to October are the best months.

Garden Mulching & Liming

The garden can be improved and capping prevented by mulching or throwing a layer of loose organic material on the soil. Bulky organic matter like straw, peat, lawn mowings or even soft green hedge clipping, just scattered on the soil will prevent the surface becoming compacted, slow down evaporation by holding moisture, smother weeds before they grow and slowly rot into the soil.

It sounds almost too good to be true, but there are possible snags. As always in the garden a balance has to be kept and while increasing bacterial activity in a mulch on the surface, a gardener can be robbing soil below of nitrogen. So a quick acting nitrogen fertiliser added ten days to a fortnight after mulching will correct the condition.

Mulching may look untidy, particularly with straw, but the benefits are considerable and many gardeners feel that a mulch spread between rows of vegetables like peas and sprouts helps prevent their own feet trampling the top soil solid.

The last main problem of mulching is that when vegetable material breaks down it creates acids. These are not necessarily harmful but they do slow down plant growth by interacting with materials like calcium. Excessive acidity is corrected by adding lime to the soul in one of the following forms:

1 Quicklime as the name implies acts fast. It can often generate enough heat on reacting with damp soil to serve as an insecticide.

2 Hydrated lime works at almost the same speed as quicklime but it can be handled more pleasantly.

3 White chalk or finely ground limestone has to be used in greater quantities than quicklime to achieve the same results.