Gardening with Different Soil Types

Gardening with different soil types

RSPB’s Morwenna Alldis celebrates soily fingers this month as she reveals how to work out your garden’s soil type and which plants will grow best in it.

For me one of life’s purest pleasures is to stick my bare hands into my garden soil. It instantly grounds me (no pun intended) and feels like where I’m meant to be. Last night I was naked gardening (gloveless that is!) and even after a good scrub, the cracks and crevices of my fingers still hold onto the dirt…and I like that, soily hands on my keyboard make me feel proud, like I’ve done something of real value.

Sowing seeds (credit: RSPB) 

But what exactly is soil and why is it so important?

Soil is comprised of tiny pieces of weathered rock, dead plants, and animals (organic matter), living organisms, air, and water. The Soil Association describes soil as: “one of our most important natural resources. It is the planet’s skin, a rich and complex ecosystem that provides the life systems we all need to survive - oxygen, clean water and food.” Soil is also home to billions of different organisms and provides most of the antibiotics we use in medicine.

Garden soil deserves our close attention and care, and we need to get to know it to effectively grow in our green spaces and help improve the biodiversity and nature-health of our local patch. Even if you only have a tiny strip of soil like me, it’s still an essential part of the UK’s largest nature reserve, a.k.a. our gardens minus the fences.

What’s your type? – of soil that is!

I didn’t even realise until researching this blog that in the UK we have six different soil types. Discovering which type you have in your garden will enable you to plan how to look after it, to get the most out of it, and which plants will grow best there. So be brave, let your gardening gloves come off and get stuck into some mud. You need to feel the texture of your soil to help determine what type it is and take note of its colour and how well it drains. The particle size of soil determines how much water and air can circulate through it, which in turn affects its drainage, nutrient levels, and how easy the soil is to work with.  

Here are the key characteristics of our six soil types to help you identify yours and the plants that favour them. A special thanks to flowerpotman for their great plant lists:

• Chalky: can be light or heavy, a stony soil as it sites over a bedrock of lime or chalk stone. It’s alkaline, so avoid planting acidic loving plants.

Best UK Wildflowers to grow: Agrimony, wild basil, lady's bedstraw, birds-foot-trefoil, burnet Salad, wild carrot, cowslip, oxeye daisy, rough hawkbit, common and greater knapweed, black medic, wild mignonette, hoary plantain, field and small scabious, selfheal, kidney vetch, yarrow, yellow-rattle/field scabious.

Veggies: spinach, beetroot, and cabbage

• Clay: feels heavy, lumpy, and sticky when wet, very hard when dry - cracks in the summer heat. Poor drainage, but nutrient rich so great for growing in.

Best UK wildflowers to grow: yarrow, oxeye daisy, musk mallow, cowslip, birdsfoot trefoil, red clover, ragged robin, white campion,

Veggies: summer crop vegetables and fruit trees

• Loamy – fine, damp texture, which can be moulded without stickiness. One of the best soils to garden with as it’s a mixture of clay, sand, and silt. Great drainage, lots of nutrients, doesn’t dry out in the summer and so can support a range of plants.

Best UK Wildflowers to grow: bladder campion, common sorrel, yellow rattle, meadow buttercup, selfheal, cowslip, hoary plantain, ribwort, musk mallow, birdsfoot trefoil, oxeye daisy, rough hawkbit, field scabious, meadow cranesbill, lady's bedstraw, common knapweed, yarrow 

Veggies: most vegetables and berries

• Sandy – gritty to touch, feel the grains of sand and not mouldable. Free draining, can dry out fast. Low in nutrients (washed away in the rain) so it needs organic matter added to sustain plants and hold moisture.

Best UK wildflowers to grow: lady's bedstraw, common birds-foot-trefoil, bladder campion, wild carrot, oxeye daisy, dandelion, field forget-me-not, rough hawkbit, common knapweed, musk mallow, black medick, wild mignonette, hoary plantain, St Johns-wort, selfheal, kidney vetch, vipers-bugloss, weld, yarrow, yellow-rattle, field scabious.

Veggies: root vegetables, lettuce, tomatoes, squash, and strawberries

• Silty­: soft and floury to touch when dry, holds moisture and creates a smooth wet mud that can be moulded. Great for nutrients and easily compacted. Can be washed away or eroded by wind – add organic matter to help bind its fine particles.

Best UK wildflowers to grow: Most vegetables and plants do well, as well as willow, birch, and dogwood trees

• Peaty: dark soil, feels damp and spongy if squeezed. High in organic matter, acidic, moisture retaining so can get water-logged, and low in nutrients. Not often found in gardens.

Best plants and veggies to grow: heather, witch hazel, lantern trees, brassicas, beans, root vegetables and salads

**Please remember that when purchasing compost or pre-potted plants ensure they are peat-free. By choosing peat free compost when gardening, you’ll be helping to keep peatlands, a precious ancient habitat, alive. Storing an estimated 3,200 million tonnes of carbon (CO2), UK peatlands are important for nature and climate, providing a vital home for a variety of plants and wildlife.

Peat free compost (credit: RSPB)

What’s your soil’s PH?

Yes, your soil will also have a PH rating, below 7.0 is acid, above is alkaline and bang on 7.0 is neutral. Which end of the scale your soil falls will also affect the sorts of plants you can grow. You can purchase an at home soil PH testing kit from many garden centres and once you know your rating you can alter that PH value by adding for example lime to soil to increase the PH or an acidifier, such as sulphur, to lower the P.H. Again, take advice from your local garden centre. The website Plant Wild also has a useful table of which wildflowers to grow in neutral, acidic or alkaline soils here.

Grass snake resting on a compost heap (credit: RSPB)

How to keep your soil healthy

No matter which type of soil you discover in your garden, they all benefit from the addition of organic matter, the decomposed remains of soil organisms and plant matter, which will provide an essential health-boost to your garden. Organic matter helps soil hold onto moisture, so that it can absorb more nutrients, it’s food for all the tiny micro critters that live in our soil, and it sticks together soil particles so that air and water can move more fluidly through it. 

When used as a mulch, organic matter such as compost, leaf-Mold, bark, woodchip or grass clippings will suppress annual weeds, whist improving water retention and soil structure as it decomposes. It will also prevent soil erosion on sandy soils and capping on clay soils. 

The correct choice of mulch is important: 

• Don’t use woody material if it is to be incorporated into the soil (e.g., in a vegetable bed) as this can lead to a temporary nitrogen deficiency. 
• Chipped bark can be acidic, mushroom compost is unsuitable for acid loving plants. 

An easy way to add organic matter into your soil is through compost, so don’t delay in starting your own compost bin today…if you haven’t already. Compost also provides a cosy home for woodlice, worms, toads, and grass snakes. And it helps to transform your kitchen and garden waste too into something beneficial you can put back into the earth – and so the circle of nature happily continues. Check out our step-by-step guide on how to make a compost bin in your garden, here.

Following these top tips you’ll get to know your soil inside out just in time to start preparing the ground for planting season. Happy gardening, here’s to grubby fingers.

 Grubby fingers (credit: RSPB)

The Soil Association describes soil as: “one of our most important natural resources. It is the planet’s skin, a rich and complex ecosystem that provides the life systems we all need to survive - oxygen, clean water and food. It is no exaggeration to say that civilisations rise and fall according to the health of the soils on which they are built”.