Your guide to caring for garden soil

A loose soil rich in humus and nutrients, with a slightly acidic to neutral pH value, is optimal for most garden plants. You'll rarely encounter such ideal conditions, but you can call upon centuries of garden wisdom to help improve it.

Soils can be divided into light sandy soil, heavy clay soil, and medium loamy soil on the basis of their sand, clay, and loam content, plus lime and humus.

• Sandy soil is easy to work and plant roots can spread out easily, but water and nutrients are poorly absorbed. Use compost to increase the amount of humus and mulching to prevent rapid drying.
• Clay soil makes it difficult for roots to spread. The soil is so tightly-compacted that the roots of many plants can't penetrate it to reach water and nutrients; they quickly wilt. Loosen clay soil by adding sand and compost.
• Loam soil offers the best gardening conditions. This soil stores water and nutrients effectively, and the soil structure is loose enough for plants to root easily and reach the nutrients. By adding a little compost or organic fertilizer, you can ensure that the soil doesn't become depleted over time.

So-called indicator plants prefer certain soils. Their appearance in your garden makes it possible to draw conclusions about the soil conditions.

• Compacted, heavy clay soil attracts creeping thistle, horsetail, lamb's foot, coltsfoot, fleece flower, mullein and dandelion.
• On the other hand, dry soil is preferred by yellow chamomile, sickleweed, storksbill, plantain and white campion.
• Soil with plenty of humus attracts nettle, dandelion and chickweed.
• High-nutrient soil lures nettle, thistle, goosefoot, wild radish, shepherd's purse, coltsfoot, saltbush, nightshade, round-leaved dock (bitter dock) and chickweed.
• Clear indicators of soil low in nutrients include daisy, heather, common sorrel, dog daisy, common wood sorrel, pansy and white clover.

Determine soil types before you get started on your gardening to ensure you choose the right one.

• Take a shovel sample at several places in the garden. Dig to a depth of about 50 centimetres (20 inches) to get your samples; you should quickly be able to tell whether the soil is sandy or loamy, dry, rocky or compacted.
• Alternatively, determine soil conditions by studying the roots of plants currently growing in the garden. A small root ball and crooked, intertwined root strands point to impenetrable soil.
• Look for creepy-crawlies. They may not look pretty, but the presence of many helpers such as woodlice, earthworms and millipedes in the soil are signs of good soil quality.