As much as 75 percent of plant matter that falls to the soil is likely to be made up of water. The rest will be composed mainly of carbon, with oxygen, hydrogen, and inorganic materials also present, together with nitrogen, phosphorus, potassium, sulfur, calcium, magnesium, and trace elements or “micronutrients,” all of which will be released during decomposition. Once the organic remains hit the warm soil, a veritable army of soil organisms attack them. As gardeners, we usually wait until our compost has finished, or nearly finished, decaying and has turned into dark, crumbly humus. Adding well-rotted organic matter to soil literally brings it to life.

Organic material

There are plenty of organic materials available to add to your soil and the choice of what to use will have more to do with where you live and what is available, rather than what might be best.

The right time to add organic materials is whenever you can get at the soil. On preparing a new or renovated border for planting, take advantage of the opportunity to dig in plenty of humus before filling the ground with plants again. In an ideal world, it is good to rest the soil after digging, to enable it to settle and off annual weeds brought to the surface. In practice, planting often has to start straight away. In this case, always tread fluffed up soil down first, to avoid sinkage later. As long as all organic material, especially manures, are well rotted, there should be no harm done to the plants. Where just a few new plants are being added, clear as large an area as possible, fork over to break up compaction, and then fork in well-rotted matter.

For vegetables, digging and conditioning usually takes place during the preceding autumn and winter. The advantage of making 4-foot wide deep beds is that an initial digging is often enough for several years. As long as you never tread on the soil, you can top-dress with organic matter every year instead.

Where plants are established, add 3 inches deep organic-matter as a mulch spread over the soil and around the plants. But brush the mulch away from the woody bases of trees, shrubs, and some herbaceous perennials, to avoid it piling up and rotting the stem.

Further Readings:

• How to Use a Hoe in Your Garden
• How to Choose the Materials for Your Garden’s Horizontal Surfaces

Depending on the geology of your area, you could end up with a garden on well-drained but poor sand, or rich but sticky clay. Some soils are acidic and others alkaline, and this will affect the way they behave and the plants that can be grown. If you don’t know much about your soil, take a good look at it before choosing plants. Life for a gardener is much easier if you garden in harmony with your soil and climate rather than fighting against it. Decide what your soil has to offer, choose the plants to suit it and you’ll avoid a lot of unnecessary struggle. Knowing more about your soil will also I help decide how best to make improvements.

Soil structure

Soil structure is a fascinating subject and the chemistry of the way soil particles behave, how they stick together and generally relate to one another, and to water and nutrients, is complex. Clay and humus are central to the dynamic nature of soil, because it is over their surface areas that chemical reactions and nutrient exchanges occur. Ions (electrically charged atoms or groups of atoms) are attracted to their surfaces and nutrients are held safely, to be released slowly for plants. Bridges are built between particles too, helping the soil maintain a granular structure.

A simple way to test your soil

- You can learn a lot just by looking hard at the consistency of your soil. A basic test is to take a handful of damp soil, squeeze it together and attempt to throw it up and down gently like a ball. Sandy soil won’t ball together much at all and falls apart at the first attempt, feeling gritty to the touch. A good, balanced loam (what we all want) will form a ball and will break apart after the second or third throw. A sticky, solid clay forms a solid ball you could throw up and down forever.

Handpicking of perennial weeds is useful, but more certain results can be obtained by using a weedkiller containing glyphosate. This is a translocated weedkiller which is absorbed by the foliage of the weed and then transmitted throughout the sap stream, kill­ing the plant entirely but not polluting the soil. Early spring is the ideal time to make an application, just as the plants are begin­ning to shoot, for the chemical is more readily absorbed and translocated at this time. Spraying in spring usually catches any pieces of root missed during handpicking as these will also be producing small shoots.

There is not a lot of difference between planting a new border and refurbishing an existing one. An existing border will doubt­less contain a number of plants that resent disturbance, or in the mixed border there will doubtless be shrubs that must be worked around. Some herbaceous subjects resent disturbance so much that they sulk and refuse to flower for several years after being moved plants like paeony and Christmas rose as well as any members of the pea family, such as Russell lupins. These must all remain where they are, unless they are exhausted, when plants like lupins can be increased by cuttings of young shoots taken as they emerge from the crown in early spring.

Once soil preparation is completed, the areas which various groups of plants are going to occupy can be marked out with sand. It is useful to have an idea of where you are going to put each plant variety and I find a rough sketch on paper a useful guide. Do not be hide-bound by your original ideas as these were in all probability made at the kitchen table and imagination and reality do not always tie up. Use the sketch as a basis upon which to work. Do not be so dogmatic that you have no flexibility. As long as certain basic principles are adhered to there is little that can go wrong in the planning of a mixed or herbaceous border. The arrange­ment of colour and Contrast is purely per­sonal, so are shapes and heights, and their combinations. What is not flexible is the quantity of plants necessary to create a satis­factory effect. Single plants do not create an attractive picture, nor in a cottage garden context do square, circular or oblong blocks of plants. Do what you wish about colours and contrasts, but stick to groups of five, seven or nine plants and arrange them in an irregular fashion.

To improve light soils, moisture-holding materials such as cow or pig manure, or old leaves and compost, should be incorporated. Artificial fertilizer should only be used dur­ing the active growing season, for if applied during winter the rain will almost certainly wash it out of the soil before it has an opportunity to work. Regular hoeing during the summer assists with retaining moisture, while surface mulches of old leaves or rotted lawn mowings around individual plants are most beneficial.

Heavy soils, conversely, require lighten­ing and opening up. This can be done by digging in quantities of straw, strawy manure, sand, grit, clinker or indeed any other material of a coarse texture. On clay soils with a relatively low alkalinity, hyd-rated lime can be used. When spread evenly over the soil surface and then lightly raked in it causes flocculation of the clay particles – the collecting and separating of colonies of tiny particles which under the physical influence of the lime form larger particles, which in turn makes the soil lighter.

Soils of many varying textures and consti­tuents exist, such as peaty, alluvial, marl, and others too numerous to consider, but all can be classified with some degree of accur­acy under the heading of light or heavy. However, apart from visible physical char­acteristics there are those unseen, particu­larly acidity and alkalinity, which are of equal importance but more difficult to ascertain. A pH test – obtainable in kit form from the local garden shop – has to be employed to determine the acidity or alkali­nity of the soil. The theory and reasoning behind this is complex and irrelevant at this stage, but it is sufficient to say that a pH of 7.0 indicates a neutral soil, one higher, say of 8.0 alkaline, and those of lower numerals acid. Careful observation of local wild flowers will also yield much information.

Where heather, foxgloves and sorrel flour­ish the soil is invariably acid, but where vetches, cranesbills and old man’s beard thrive then it will almost certainly be alka­line. These conditions can have a marked effect upon plant growth; where such con­ditions may pertain.

Further Readings:

• How to Improve Soil Drainage in Herbs Garden
• How to Transplant Flowers