Fundamental information on soil quality
Just take a glance at the plants in your garden and you can see whether they are taking root in fertile loose soil or are finding it difficult to find enough water and nutrients. In order for them to flower and germinate, they must receive appropriate amounts of minerals, air, water and organic substances. Sandy soil, for example, is light and porous to water and is easy to work, but it stores no nutrients. Clayey soil, on the other hand, is heavy, lumpy, compacted, quickly flooded, and goes as hard as concrete in dry weather. So what is right for healthy growth, then? Ideal soil combines the advantages of sandy and loam soils, because it holds water and nutrients with its high proportion of humus, is porous to oxygen, and is easy to break up. You can determine the quality of the soil in your garden quickly and easily using the finger test: Simply moisten the soil and rub the sample between your fingers. If the soil runs through your fingers it is sandy soil. If you can knead the soil into a crumbly sausage shape, it is a loamy-sandy soil. Loamy soil makes a firm sausage shape. The best way to find out whether the soil in your garden is acidic or alkaline is to do a soil pH test.
Good soil has worms in it
The magic remedy for improving the quality of all garden soils is humus. If you work bark humus or sand into heavy, loamy garden soil, for example, this will improve aeration. The most avid and reliable producers of humus, however, are the countless micro-organisms which abound in the soil and put in a lot of hard work. One gram of humus-rich soil is home to over one billion tiny soil organisms. They loosen the soil by rifling through it and convert organic matter into valuable humus. The most prominent of these micro-organisms is the earthworm. So if there are worms in your soil - all the better. A large number of earthworms is a reliable indicator of good soil quality.