Soil management

The ideal soil has a good crumbly structure, is rich in organic matter, drains well enough to prevent the topsoil becoming waterlogged in heavy rain, and is capable of providing the nutrients needed for healthy plant growth. The various soil types described on the left all have their own advantages and disadvantages. Each type is in fact a mixture of different particles in varying proportions, and a short period of observation and a test will soon establish which mineral predominates. You can then use one of the following management techniques to get the best from your particular soil.

Clay

While clay is beset with problems initially, a little work and sound management can produce excellent results. It is certainly true that, in the early stages of cultivation, clay is not nearly as convenient to work as a light soil such as sand. When it is wet, it rapidly becomes a soggy mess of mud and, when it dries out, it sets like concrete. Clay is a badly drained, cold, and heavy soil because the spaces between each particle are too small to allow free passage of water and air, so the soil is always in danger of settling down to form a solid, airless mass. Improving the soil structure can take a few years, but a good clay soil is capable of growing far better crops than a sandy soil ever could.

DIGGING

It is best, if you can, to dig a clay soil during the fall, either at a time when there has been a little rain to soften the hardbaked soil, or when it is drying out after being soaked, but before it is hard again. In temperate climates, these times are fairly frequent, but in drier climates it calls for good organization and rapid action when the weather changes. When heavy soil gets wet and dries out again, it expands and contracts, causing the mass of soil to crack into innumerable small clods. If water then gets into these cracks and freezes, it will force them further apart, breaking the soil down to a sowable tillage. So dig clay soils in the fall, leaving the surface rough and uneven through the winter to expose the maximum amount of soil surface to the elements. At the same time, you can work the organic material into the upper levels.

DRAINAGE

Because clay was broken down chemically, it’s also possible to combine the particles chemically by a process known as “flocculation.” If sufficient lime is added to the soil, the tiny particles of clay will bind together to form much larger crumbs, through which air, water, and plant roots can freely pass. Check the requirements of the plants you want to grow and use as much lime as you can without making conditions intolerable for them. In addition, if your soil is very heavy, dig coarse sand into the soil—approximately one to two bucketfuls every square yard/meter. Raising a section of soil above its immediate surroundings will improve drainage considerably, helping the soil dry out and warm up; raise your ornamental beds slightly and grow your vegetables on the deep bed system. The important thing with clay is that you should never walk on it when it is wet or you’ll destroy years of work. If you have to walk on it, lay boards down first.

ORGANIC MATTER

Adding plenty of bulky organic matter to a clay soil will hold the particles apart so that roots and water can pass through. After a few years, when the level of organic matter is satisfactory and the soil is filled with the roots of previous crops, clay becomes much easier to work. In fact, every plant you grow plays its part in improving the soil for the next plant generation.

Silt

The main problem with a silt soil, as with clay, is one of drainage. Of all the soils formed by grinding, silt has the smallest particles. Only the particles of clay are smaller, but they were formed by chemical action. The size of the particles means that they tend to pack together very closely when wet, preventing the free passage of water and air through the soil. So drainage is poor and there is a danger of the soil settling down to form an airless mass. However, if you never walk on the soil when it is wet (use boards) and condition it as recommended here, silt is perfectly manageable and will produce satisfactory results.

DIGGING

Silt soil should be cultivated only when it is dry enough not to stick to your boots. Conditions underfoot permitting, aim to dig silt during the fall to take advantage of weather which will help break the soil down to a sowable tillage. Like clay, when silt gets wet and dries out again, it expands and contracts, causing the mass of soil to crack into small clods. If water then gets into these cracks and freezes, it will force them further apart, breaking the soil down even more. So by digging silt over in the fall, you expose the maximum amount of the soil surface to the elements and work the organic material into the topsoil at the same time.

DRAINAGE

In order to improve drainage, the soil particles have to be forced apart physically to allow free passage of air, water, and plant roots. Do this by digging one or two bucketfuls of coarse sand into the soil every square yard/meter (see p. 75 ) when you dig in the organic matter. Raising your ornamental beds slightly and growing vegetables on the deep bed system will improve drainage, helping the soil dry out and warm up.

ORGANIC MATTER

The structure of silt soils benefits greatly from the addition of liberal quantities of well-rotted compost or manure. Adding plenty of bulky organic matter to the soil will hold the particles apart so that roots and water can pass through more easily. If possible, keep the soil covered with a green-manure crop in order to add organic matter and remove surface water (see p. 32).

Sand

A very light soil, sand tends to drain easily and can therefore be cultivated when other soils are lying sodden and unworkable. As it also warms up quickly, it is an ideal soil for raising early crops. However, sand is also hungry and very demanding. So the price of having an easy soil to work is the need to apply extra organic matter and plant food, in the form of fertilizers (see pp. 35–42), because nutrients, as well as water, will drain away.

 DIGGING

When you cultivate sand is relatively unimportant. It is not necessary to leave a sandy soil rough during the winter months for the frost and rain to break down. The large particles make it very easy to cultivate to a fine tillage anyway, so it is best to dig it in the spring a short while before you intend to sow or plant. If you never venture on the soil when it is so wet that it sticks to your boots, you will not go far wrong.

DRAINAGE

During the year, sandy soil will tend to lose water, both through surface evaporation and free-draining, and this could be detrimental to the plants. To reduce the problem, spread organic matter, or mulch, over the beds between plants as often as you can. This lowers the evaporation rate and improves the soil structure.

ORGANIC MATTER

It is very important to improve sandy soils by adding substantial amounts of bulky organic material each year. Because of the quick-draining nature of the soil, the organic matter will work down into the subsoil very quickly so, to save work and to put it in the root zone, dig the organic matter into the top few inches or spread it over the surface. Try to maintain a cover of vegetation over the surface more or less all the time, and certainly in the winter, when the “leaching” of nutrients is at its most rapid. In the vegetable garden, it is a good idea to grow a green-manure crop during the winter when the beds are empty and to dig it in during the spring. This will not only hold many of the nutrients in the soil during the winter, but will also add large quantities of organic matter.

Chalk

There are two big disadvantages with chalk soils. Firstly, they are thin, dry, and “hungry.” This is because the particles are very large, like those in sandy soil, so water drains through rapidly, taking plant nutrients with it. Plant nutrients, in the form of organic fertilizers, will therefore need to be added to the soil. Secondly, perhaps even worse, chalk is a very alkaline soil, and so unsuitable for many plants.

DIGGING

Generally there is no need to worry too much about the timing of cultivations. Like sand, chalk soils are normally dry enough to work, even in the depths of winter. It is not necessary to leave a chalky soil rough during the winter months for the frost and rain to break down. Instead dig it in the spring a few weeks before sowing. Because the topsoil is usually not very deep, digging should be kept shallow and, if the area is fairly small, it could be worthwhile adding a layer of topsoil to the surface.

DRAINAGE

Generally, drainage on chalk soil is too good and the need is to retain water and nutrients. This can be done by adding bulky organic matter that will also help to acidify the soil.

ORGANIC MATTER

On chalk, more than any other type of soil, it is important to try and keep the soil surface covered. Grow a crop of green manure during the winter and dig it in during the spring. During the growing season, it is even worth sowing a fastgrowing green-manure crop between vegetables, just to keep the soil covered. Mulching, or spreading organic material on top of the soil between plants, is also important during the growing season. You should use acid materials, such as peat, grass cuttings, compost, or manure, in order to counteract the alkalinity of the soil.

Peat

If you are lucky enough to be growing on peaty soil, grow as intensively as you can, as it is always potentially very fertile and usually easy to work. You’ll find it easy to produce bumper crops and beautiful flowers year after year. Properly managed, a peat soil is superb but, like other soils, it does have its problems. Most importantly, peat soils are liable to be acidic and will therefore need generous applications of lime to restore the pH balance in the fruit and vegetable plots. In the ornamental garden, provided you choose the correct plants, this should not be necessary. Furthermore, when they are drained, peat soils tend to dry out quite rapidly in hot weather. If they are  allowed to dry out completely, they will shrink and may be difficult to get wet again. To prevent this, some hand watering may be necessary in dry weather.

DIGGING

The timing of cultivation is not critical. It is not necessary to leave peat rough during the winter.

DRAINAGE

Moorland and fenland peats are often badly drained so you may need to install a drainage system.

ORGANIC MATTER

A major advantage of peat is that it is not normally necessary to add any humus-making materials. Peat, unlike the other soils, is largely made up of decomposed matter. It therefore has a low mineral content but contains an excess of  organic matter. However, the soil is likely to below in nutrients to start with so you may need  to add fertilizers.