Selecting and arranging plants in the garden is probably one of the most rewarding tasks for any gardener, and one that many of us devote lots of time and thought too, but how many of us can say the same for the soil in which those same plants will have to grow?
Good old garden soil isn’t as pretty, glamorous or tasty(?!) as the flowers, trees and veg that it supports, but getting to knowing your soil, it’s limitations and benefits, must be one of the most useful things you can do in any plot. It will allow you to determine the range of plants best suited for success in your particular garden, and so minimise disappointments, and will also let you figure out the best methods to improve the soil you already have.
There are five different types of soil found in British gardens. Any given site can, of course, have a combination of several of these types, and there are also gradations between types, as well as extremes of each, where the gardening is at it’s most challenging. Being able to recognise your particular soil types is probably the best place to start in any garden.
Clay.
A pure clay lump - typical of subsoil that has been brought to the surface.
All soil types are, to a large extent, determined by particle size and clay soils have the smallest particles of all. Pure clay – which makes up much of the British subsoil – is just like modelling clay, the sort of thing you’d expect to find spinning round on a potters wheel. Put a glob between your fingers at it will feel smooth and putty-like.
Most clay garden soils aren’t quite as extreme as that – although individual, fist-sized balls of pure clay are not uncommon even in topsoil, and are typical of new gardens where the subsoil has been disturbed and brought up to the surface by building work.
The great benefit of a clay based soil is that it is extremely nutrient rich and capable of supporting a very wide range of plants. The downsides are all to do with that tiny particle size. When wet the soil is extremely heavy and frustratingly difficult to dig and work with. It can also be easily compacted, driving all of the air out and forming a dense, thick layer that roots can find all but impenetrable. Although clay soils are naturally very moisture retentive – which can be handy in a dry summer – when they do dry out they bake into an extremely hard, cracked surface pan which is, once again, completely unworkable.
Sand.
Sandy soil - open and free running.
A sandy soil is one with a very small percentage of clay particles, where the large bulk is instead made up of much more coarse quartz and silica originating from weathered rock. Take a chunk of this between your fingers and it will always feel gritty and loose. Unlike a clay soil, sand-based soils will never “clump” and will always be more-or-less free running when you dig through them.
Sandy soils can make for fantastic cultivation options; they warm up very easily in the spring and so promote a long growing season, they will never be water-logged and are easily worked at any time of the year. The major downsides are to do with fertility and water-retention, which are both pretty poor, or in extreme cases, non-existent. A wide array of drought tolerant, generally surface rooting plants have evolved to specialise in sandy soils, but unless you are happy to stick with these, a sandy soil will require ongoing maintenance to allow for a wide community of plants to flourish.
Loam.
Lovely loam - nutrient rich and easily worked.
Loam is a kind of generic term given to the ideal garden soil that consists of a roughly equal mixture of clay and sand, and which brings the benefits of both soil types with few if any of the disadvantages.
Loam soils are open, and easily worked but full of nutrients. They are moisture retentive in summer but free draining in winter.
There is no doubt that a loam based soil will support the widest range of garden plants with the least amount of alteration and soil maintenance. Very few “wild” soils are naturally loamy – river basins and flood plains with millennia of silt deposits are perhaps the main exception – although having a loam garden soil is, understandably, an ongoing holy grail for most gardeners. Continued cultivation and improvement will gradually move any soil towards a loamy condition.
Chalk.
Chalk soil - typically very shallow and stony.
Certain localised regions of Britain have naturally calcareous or chalk-based soils, all of which are derived from weather limestone, which is itself the result of deposition in ancient, long-since-disappeared oceans.
Chalk soils are identifiable by their light colour. They are generally very stony too, with pieces of pure calcium chalk in the mix. They can be wet and difficult to work in winter but bone dry and rock-like in summer, and their overall nutrient level is low.
Again, a specialised wild flora has evolved to thrive on chalk soils, but many cultivated plants will find conditions much tougher. Most garden plants require acidic to neutral soils in order to be able to access the full range of nutrients that they need. Chalk soils, though, are inherently alkaline in nature and, unless you plan on replacing the entire top soil, that’s not something that can be fundamentally changed.
Peat.
A very pure, black-peat soil.
The other localised soil type, and at the other extreme from the chalk soils, are the peat-based soils. All of these soils occur in regions that were once marshland, and the peat is the result of many millennia of rotting plants all deposited and compacted.
Peat-based soils are, of course, naturally acidic, and very dark in colour ranging from dark brown to pure black bog peats. This dark colour ensures that the soils warm rapidly in spring and like loam soils, provide for a long growing season. They are also recognisable for being very light and crumbly in texture but having a poor range of nutrients naturally available.
Depending on where they are located peat soils may either be very wet and still marsh-like year round or, where the geology has displaced and raised the ground level, seasonally dry and easily cultivated. Again, a range of plants have evolved to specialise in peat-soils, and so long as the area isn’t water-logged, the gardening possibilities are rich and extensive.
Tags: Flowers, Garden, Gardening, Native Plants, Nutrients, Plants, water, Watering, Wild Flowers
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