05 October 2015 By Matthew Haddon
Although I may curse when clay-laden earth is clagging up my boots and tools, soil is truly an amazing thing. Too often we look to the plants first and forget that it is the soil that provides them with almost everything that they need.
It is its very diversity which makes it fascinating; clay or loam, sandy or chalky, compacted or aerated, water-logged or dry - understanding our soil is fundamental to our success as gardeners. Luckily for us there are plants adapted to every soil condition (which will be why plants make up around 99.7% of the mass of living organisms on the planet).
Healthy soil is just as important as planting the right plant in the right soil. This is why we don’t walk on it when wet (compacting the soil, sealing the gaps within which roots can find oxygen and water) and why a good mulching of organic matter (feeding the animal life within the soil, whose waste products then feed the plants) is so important.
Indeed life teems in the soil (providing you are not using harmful chemicals) and mostly to the benefit of our plants - it is an oft quoted fact that there can be up to a billion bacteria in a teaspoon of soil, although such numbers are hard to comprehend. Add to this plethora of life the worms, invertebrates, nematodes and fungal filaments and soil is truly a microcosm of life, even before we begin to add in the plants that we humans appreciate so much.
In the greenhouse though areas of open soil have a greater chance of soil borne pathogens accumulating, to the detriment of your plants (especially if you re-plant similar crops each year). As the season comes to a close therefore it may also be a good time to dig out the old soil and add back some fresh loam (as long as you take extra care if the glazing reaches soil level, as one tap from a spade might spoil your weekend!)
Matt Haddon is a Landscape and Garden Designer based in Yorkshire.