Digging soil – how and why?
Get the soil right and you get gorgeous garden!
Soils come in a variety of forms and they can vary even within your own garden too. Soils are described as either acid, neutral or alkali and different plants fare better in certain situations.
Understanding what your soil is like helps determine what will grow well. Knowing the type of soil and planting to suit lead to a better garden and much less work for you.
You can go out and buy a soil test kit, but use your neighbour’s gardens as a good indicator. Have a look what seems to be growing well in neighbouring gardens; if the plants are thriving there, then the chances are they will thrive in your garden too.
Acid soils tend to favour Rhododendrons, Azaleas Camellias, also look for Heathers growing around and about. Hydrangea flowers go blue in acid soils, If your natural soil is quite peaty, then this usually indicates the soil is quite acidic too.
Acid loving plants will not thrive in alkaline soils. Chalky soils are usually more alkaline, but most plants will grow quite happily in alkaline or neutral soils.
Acid or alkaline is only part of the story however, your soils will also have a certain characteristic that dramatically affects whether plants will thrive or limp along, and these soil types need to be looked at.
Generally they are classed as; poor, sandy, clay, stony, waterlogged and loam. so how do you know what yours is and more importantly, what needs digging into soil to improve it before planting.
These are characterised by a number of factors, they are generally pale in colour. When you dig into the soil it is compact, hard and you generally find very few bugs. In winter it may puddle up and in summer it bakes as hard as concrete.
If you can’t easily push a metal fork into the ground, then most plant roots will struggle to fight their way through too. Add food and fibre to improve things. Fertilise to bring much needed nutrition and fibre to help break up the soil and keep it light and loose. This can be achieved by adding well rotted manure (food and fibre) or a bought fertiliser to scatter on the surface. To this you add ground conditioner or soil improving compost which is a fibrous mix which you work into the soil. Don’t scrimp on volume add a good 10cm layer of manure / compost on the surface and dig this into the ground.
Sand is a very efficient medium for water to drain through very fast, so sandy soils dry out very easily. Even with a heavy shower, the water drains through the soil too quickly for the plant’s roots to get a good drink. Grab a handful of the soil and squeeze it, if it won’t stick together the soil is pretty sandy. It is easy for plants to push their roots through, but then they struggle for water. In this case, add fibre which will absorb moisture and thus allow the roots time to extract the water before it seeps away. Well rotted manure or compost is ideal for this, so again add a good 10cm thick layer where you want to plant. Lightly fork it in, the worms will generally do the rest for you.
Like sandy soils, water tends to drain away pretty quickly, it is also a real pain to try and dig. If you intend to grow root vegetables, remove as many of the larger stones as you can, otherwise you will get very wonky carrots. The problem with really stony soils is that stones don’t contain much nutrition for plants, and so will struggle to get going. Remove as many of the stones as possible, add lots of well rotted compost which will hold onto moisture and provide nutrition to the plants. If you really aren’t able to remove the stones, choose plants that thrive in these types of soils. plants like grasses, lavenders, thymes, and other shallow rooted plants.
This is made up of very tiny particles, which over time settle down to form a compact soil. Clay soils dry out and bake hard in the summer and is a soggy clumpy mess in winter. The problem is the clay particles are so close together air and water can’t easily pass through. However, clay soils can be quite fertile. You need to do is add a medium to it that will prevent the clay from clumping together. This can be ground conditioner, or well rotted compost. It’s best to add this to the soil in the Autumn or Spring, it is generally easier to dig. Try to avoid digging clay on a wet soggy day – it’s back breaking and end up in a bit of a quagmire. Keep on adding compost to it each year and you should end up with a beautifully fertile loam.
An area that stays damp all Summer but ends up a permanent puddle in winter. There are a few reasons for this, firstly it is in a natural hollow and so collects all the moisture. The water table is high and sits just below the surface or that the soil is so compacted water just cannot drain away easily. Plants can thrive in these conditions, but many won’t as their roots just drown and rot in the water. To improve the soil though you need to concentrate on drainage. Adding horticultural grit in the bottom of planting holes will help the plant sit above the water, failing that, build a raised bed and plant into that.
This is what you are trying to achieve, a dark earthy smelling soil with lots of insects and earthworms in it. After you have finished digging, you should be able to push your fork or spade into the soil easily. Try and ensure large clumps of earth are broken up and if possible remove larger stones and any old roots or weeds. Then all is ready to plant.
NB: There are also peat based soils, but in the UK these tend to be confined to the more remote parts of the countryside, most gardens are unlikely to be purely peat based, although some soils would tend to be more acidic in areas of the country where peat soils are more common.