Monty unravels the secrets of soil
Healthy soil is the key to successful gardening, says Monty, in this exclusive extract on the underrated stuff beneath our feet, from his newly revised practical gardening book
For most of my life I have believed that ‘improving’ the soil was the holy grail of gardening. Lick your soil into shape and your garden will inevitably become better, too. I also believed that soil had moral as well as practical qualities, and was a kind of qualitative measure of the gardener. Good, rich soil exemplified the work of a good, hard-working gardener. But over the past few years I have changed my view on this. It is not completely wrong, of course, but it is only part of the truth and research over the past 25 years has made us realise two things.
The first is that soil is a very much more complex material than we had imagined. Its relationship to plants is dependent upon a chain of interactions so interwoven and far-reaching that it makes the average neural pathway look like an on/off switch. The second is that we know practically nothing about any of this. It has been said that we know more about the outer reaches of the universe than we do about the soil 15cm (6in) beneath our feet. One-third of all organisms on this planet live in the soil and yet we have so far only even identified about one per cent of them. The phrase ‘barely scratching the surface’ does not do justice to our ignorance. But every gardener stands to benefit from a little understanding of what has so far been discovered from looking at the ground that our gardens grow from.
The old received wisdom was that there were four basic types of soil – clay, chalk, sand and peat. The average garden was likely to be a composite of two of these but dominated by one characteristic that would determine the broad swathe of plants you could comfortably grow. This is still broadly true, but only as an expression of pH rather than of the soil itself. It was a given that all four types of soil would be immeasurably improved by digging
– preferably doubly so – and by adding large quantities of manure – preferably in a trench as you dug. In fact, it is now reckoned – and I stress that this science is nascent and new discoveries are being made almost daily – that there are over 50,000 different soil types around the world. Each one is a separate ecosystem with individual characteristics. Each one hosts countless organisms and biota that are all interacting as part of the life of the soil and the plants that grow in it.
Confused? Well, you might well be. In fact, if you are not floundering then you have not begun to grasp the complexity of this. Suddenly a bit of virtuous digging and a fresh load of manure do not quite cover all bases.
The nitty-gritty
Soil structure is almost as important as soil content. Get the ‘pores’ of the soil right and it permits best root development, drainage, water retention, and bacterial and rhizomatous growth and interaction. You, the gardener, cannot make this happen any more than you can make your brain process a taste. But you can help provide the environment. So adding organic material and perhaps extra grit, avoiding compaction from walking and cultivation, and using plants – even weeds – to open out the soil with their roots and add their biomass, will all help soil structure. If the structure is good, so too will be the fertility because your plants will be best able to take up available nutrients and moisture.
It is important to realise that there is no one perfect soil, and the recipe for such perfection will change with circumstance. In fact, to adapt the old adage about clothes and weather, there is no such thing as bad soil – just the wrong plants. If a plant is healthy and happy, it will not, I am afraid, be down to your tender loving care or extreme skill, but simply because it has found the right soil in which to put down its roots. Look after the soil and you invariably look after the plant too.
Thus, after half a century of believing that digging was at the heart of all good garden cultivation, I have amended my views. In order to get the best from our soil – whatever type it seems to be – we should nurture a healthy worm population. Make compost and add it thinly as a booster for the life that is already busy at work in the ground. Cut right back on the digging. Forget all notions of a ‘perfect’ soil but work at making yours as good as it might be.
Choose your plants wisely so they interact well with your soil as it is and not as you wish it might be. A healthy plant will make the most of what the soil provides, and will limit both its rate and ultimate size of growth to achieve that end. Plants will always work with the soil that they grow in. It makes sense for gardeners to do so, too.
GET THE BOOK
This feature is an extract from The Complete
Gardener by Monty Don (DK, £27), out 4 March. Fully revised for 2021, his practical gardening ‘bible’ includes organic and sustainable growing methods, in-depth guides to ornamental and edible plants, and the evolution of Longmeadow.
Receive a copy when you take out a subscription to Gardeners’ World Magazine, for yourself or for a friend, while stocks last. See p167 for details.
If a plant is healthy and happy, it will not be down to your tender loving care, but simply because it has found the right soil