Down to Earth
If you want success in the garden the first challenge is to know your soil
If you are starting a garden in a new area or even remodelling an existing one, the first step is to familiarise yourself with the soil. An easy and revealing way is to check on your neighbours. See what type of plants flourish and which are absent – if you find a common theme it’s bound to reflect on the type of natural soil.
To test your soil simply squeeze it in your hand. If the sand content is high, the particles will look and feel gritty and the soil will crumble when you open your hand. If the soil feels a little sticky, holds its shape, but crumbles when you poke, it is medium loam, the ideal soil, a gardener’s paradise. If the soil feels greasy, looks shiny, and keeps its shape then it is clay loam, which will grow most things, but is difficult to dig. If you can mould the soil, and it becomes shiny when you polish it, then it is clay, which is very hard work, but most clays are still fertile.
Soils vary, and few are ideal. Some, like the fenland silts of East Anglia, or the fertile ‘brick earth’ in the West Midlands, are so rich and easy to work that they’ll grow almost anything, with minimal effort. Others, such as the heavy, sticky clay of Northamptonshire, or boulder-strewn limestone of the Cotswolds are much more challenging and demand more careful management. But no soil is so bad as to rule out gardening.
Getting to know your soil is the first step for a successful garden. Check whether it is acid or alkaline. Find out how quickly it drains and check whether it has been well-managed in the past. Know what you are up against, and the rest becomes much easier. Not only can you take a whole variety of actions, to reduce the disadvantages, and play on the advantages, but you will also have a clear idea of which plants will thrive, which will need extra help and which are not even worth trying. One way of improving your soil is by adding well-rotted compost to it.
Clay soils are among the most difficult to deal with, but are often the most fertile. They hold nutrients that could otherwise wash through in the rain, and they are pretty good at retaining precious moisture. Take great care never to walk on clay soils unless they are dry. Even then, keep off them as much as you can. It’s best to dig them in the autumn when the ground is moist.
When you dig, consider laying a plank down, and walking on that, rather than on the bare soil, since it reduces pressure and, therefore, prevents compaction. Compacted soil contains no air, is easily waterlogged and is impossible for roots to penetrate.
Adding coarse or woody material, especially if it has been through a shredder, will help to open up the structure and will improve drainage.
If cracks appear, in summer, take advantage of this by pouring sand or coarse grit down them. Then, when the clay becomes damp again, and expands, the sandy seams will assist drainage.
The choice of plants, for clay, is vast. Roses love it and, once established, will grow well and flower for long periods. Most evergreens, particularly hollies, euonymus, laurels and box also cope well with clay. Many spring shrubs also cope well. Herbaceous plants, which enjoy moist conditions, will usually settle well in clay.
Chalky or limy soil often combines a double problem – dryness and extreme alkalinity. The former stunts growth, but the latter causes serious mineral imbalances among lime-hating plants, particularly members of the heather and rhododendron family. Dryness can be reduced by laying thick mulches, and by working as much soft organic material into the ground as possible, and repeating this treatment year after year. Rotted grass or compost made from weeds and leaves, well-rotted down, will help moisture-retaining properties, as will
developing a good, thick cover of living vegetation.
Plant densely on chalk or lime, but be very selective with your plants. Forget such lime haters as camellias or azaleas and concentrate, instead, on species which look lush but which do well in the dry. All lavenders thrive in lime or chalk.
Visit the Cotswolds, in June, and it becomes obvious which perennials love the limy conditions. Cranesbills, particularly the larger ones, will flower superbly and will usually seed around freely. Members of the scabious family, such as Knautia, Scabiosa and the teasels will also create spectacular shows for you, especially if you can set them off with tall mulleins (Verbascum) or perhaps some of the more drought-tolerant foxgloves.
Heathland, where bracken and heather do well in the surrounding countryside, means the chances are, your soil is fast-draining sand. In winter, this is easy to dig in, but in summer, it loses all its structure and, sometimes, even blows away on the wind.
Surprisingly, the same treatment that will open up a heavy clay soil will also help to improve moisture-retaining ability of sandy soils. Build on that organic matter, digging in compost year after year. The results will astound you. Throw nothing away, but rather, compost kitchen waste – as long as it is of vegetable origin – as well as newspapers, weeds, cut grass and fallen leaves.
Sandy soil provides excellent growing conditions for annuals. Many, such as poppies, will self-seed prolifically, building up self-sustaining colonies. Californian species such as Eschscholzia are as successful, on sandy soil, as are the lovely European cornfield kinds, and improved garden forms like Shirley Poppies. Good shrubs are harder to find, for sand, but there are still some dependable ones. In coastal regions, especially where rainfall is high, hardy fuchsia, tamarisk and the larger hebes all do well.
Even if you are unlucky enough to have inherited such a garden or sheer rock, do not despair! There is a small and much treasured cadre of plants that will do, even for you!
You will probably decide to grow the bulk of your garden in containers – that way, you can select any soil you like – but there will still be planting opportunities in odd corners and crevices. Among shrubs, the Aucubas can be surprisingly cooperative as long as they can gain a toehold, as is ivy, which will grow practically in the dark. Daphne laureola – fragrant green flowers in late winter, evergreen – seems able to grow in rock crevices, provided it is shaded, and for further winter fragrance. Hardy (bergonias?) bergenias seem happy almost anywhere. Their bright pink blooms, in early spring, are very cheering and the leaves often brighten in winter.
To get the best results in the garden you need to understand your soil, keep it in good condition and always consider what is happening around the plant’s roots. It’s important to make sure the feeding; physical condition and drainage of the soil are adequate and well- balanced.