Soil Types and How to Improve Them

There are basically four types of soil: light sandy, medium loam, heavy clay and chalky; but within these groups there are many mixtures, all of which can be improved and made more protective by regular and good cultivation practices. On light sandy soils, which are free-draining and dry out rapidly in warm weather, fertilizers are best applied at lower dose rates than normal, but more frequently. Applications of well-rotted farmyard manure or compost to improve the moisture and nutrient holding capacity should be regular and liberal, since these break down much more quickly in light sandy soils than in any other type of soil.

Practically all light soils, especially those with a little natural peat in their make-up or those unproved by the addition of compost, etc., are inclined to be on the acid side. So for most vegetables, with the exception of potatoes, it is wise to make an annual pre-sowing or planting level check. A reading below 6 would indicate the need for an application of garden lime. Light soils, apart from draining well, warm up earlier in the spring and are capable of producing earlier crops than the heavier. Medium loam types of soil (mixtures of sand and clay) are regarded as the best for vegetable growing and easy to work.

Heavy soils with differing amounts of clay in their make-up vary considerably, from those that are not too difficult to cultivate to the frustrating brick clay type, which, unless handled properly, is sticky in winter and rock hard in summer. Yet the soil nutrient levels are high, as are the cropping potentials. Late autumn or early winter is the time to turn the ground over to the full depth of the spade, leaving large rough clods exposed to the weather. Without the help of nature – the frost to separate the clay particles followed by March winds to dry them out – seed-bed preparation is virtually impossible; but pre- Christmas digging pays real dividends. For heavy soils, digging in some compost or farmyard manure, slightly straw rather than completely rotted, helps to keep the soil more open, improving root systems. Too much well-rotted compost or manure can increase the slug population, whereas the incorporation of well-weathered ashes tends to reduce it, and helps to make the clay easier to manage.

These same treatments improve chalky soils, but here too the real answer begins with winter digging and ends with breaking the flaking clods down in spring. Never re-dig before sowing or planting, as this will undo all your good work.