The Six Types of Soil
There are six main soil groups: clay, sandy, silty, peaty, chalky and loamy. They each have different properties and it is important to know these to make the best choices and get the most from your garden.
1. Clay Soil
Clay soil feels lumpy and is sticky when wet and rock hard when dry. Clay soil is poor at draining and has few air spaces. The soil will warm up slowly in spring and it is heavy to cultivate. If the drainage for the soil is enhanced, then plants will develop and grow well as clay soil can be rich in nutrients.
Great for: Perennials and shrubs such as Helen’s Flower, Aster, Bergamot, Flowering quince. Early vegetable crops and soft berry crops can be difficult to grow in clay soil because of its cool, compact nature. Summer crop vegetables, however, can be high yielding vigorous plants. Fruit trees, ornamental trees and shrubs thrive on clay soils.
2. Sandy Soil
Sandy soil feels gritty. It drains easily, dries out fast and is easy to cultivate. Sandy soil warms up fast in spring and tends to hold fewer nutrients as these are often washed away during wetter spells. Sandy soil requires organic amendments such as glacial rock dust, greensand, kelp meal, or other organic fertilizer blends. It also benefits from mulching to help retain moisture.
Great for: Shrubs and bulbs such as Tulips, Tree mallow, Sun roses, Hibiscus. Vegetable root crops like carrots, parsnips and potatoes favour sandy soils. Lettuce, strawberries, peppers, corn, squash, zucchini, collard greens and tomatoes are grown commercially in sandy soils.
3. Silty Soil
Silty soil feels soft and soapy, it holds moisture, is usually very rich in nutrients. The soil is easily cultivated and can be compacted with little effort. This is a great soil for your garden if drainage is provided and managed. Mixing in composted organic matter is usually needed to improve drainage and structure while adding nutrients.
Great for: Shrubs, climbers, grasses and perennials such as Mahonia, New Zealand flax. Moisture-loving trees such as Willow, Birch, Dogwood and Cypress do well in silty soils. Most vegetable and fruit crops thrive in silty soils which have adequate adequate drainage.
4. Peaty Soil
Peaty soil is a darker soil and feels damp and spongy due to its higher levels of peat. It is an acidic soil which slows down decomposition and leads to the soil having fewer nutrients. The soil heats up quickly during spring and can retain a lot of water which usually requires drainage. Drainage channels may need to be dug for soils with high peat content. Peat soil is great for growth when blended with rich organic matter, compost and lime to reduce the acidity. You can also use soil amendments such as glacial rock dust to raise pH in acidic soils.
Great for: Shrubs such as Heather, Lantern Trees, Witch Hazel, Camellia, Rhododendron. Vegetable crops such as Brassicas, legumes, root crops and salad crops do well in well-drained peaty soils.
5. Chalky Soil
Chalky soil is larger grained and generally stonier compared to other soils. It is free draining and usually overlays chalk or limestone bedrock. The soil is alkaline in nature which sometimes leads to stunted growth and yellowish leaves – this can be resolved by using appropriate fertilizers and balancing the pH. Adding humus is recommended to improve water retention and workability.
Great for: Trees, bulbs and shrubs such as Lilac, Weigela, Madonna lilies, Pinks, Mock Oranges. Vegetables such as spinach, beets, sweet corn, and cabbage do well in chalky soils.
6. Loamy Soil
Loamy soil, a relatively even mix of sand, silt and clay, feels fine-textured and slightly damp. It has ideal characteristics for gardening, lawns and shrubs. Loamy soil has great structure, adequate drainage, is moisture retaining, full of nutrients, easily cultivated and it warms up quickly in spring, but doesn’t dry out quickly in summer. Loamy soils require replenishing with organic matter regularly, and tend to be acidic.
Great for: Climbers. bamboos, perennials, shrubs and tubers such as Wisteria, Dog’s-tooth violets, Black Bamboo, Rubus, Delphinium. Most vegetable crops and berry crops will do well since loamy soil can be the most productive of soil types. However, loamy soil requires careful management to prevent depletion and drying out. Rotating crops, planting green manure crops, using mulches and adding compost and organic nutrients is essential to retain soil vitality.