Chalky soil is far from being the ideal garden soil. However, plenty of varieties of flowering garden plants, trees and shrubs thrive in chalky soil. Maximise the beauty of your garden and save yourself the hard labour of significant soil amendment by choosing plants proven to grow well in chalky soil.
Characteristics of Chalky Soil
Chalky soils contain lime or calcium carbonate, which make them basic or alkaline with a pH level higher than 7.0. Just like sandy soils, chalky soils erode and dry out easily. They may contain pieces of chalk and have high flint content that can pose a challenge when digging and cultivating plants. Chalky soils are often rich in natural fertiliser, though their high alkaline content often blocks nutrients from passing through the roots of plants.
Testing for Chalky Soil
Finding small pieces of chalks in your soil can indicate that you have chalky soil. Another way to test is to mix your soil with vinegar. Chalk has high calcium carbonate content, which reacts when mixed with vinegar. This simple test will reveal chalk particles, if any, which are too small to see. Use soil test kits available at your local garden store to check on your soil's pH level content.
Pros and Cons of Chalky Soil
Chalky soil has some advantages when it comes to growing plants. It drains well and warms up fast in spring. During rainy season, it's easier to cultivate chalky soil than clay soils. Apply extra effort when digging chalky soil when mixed with clay soil in its wet state. Adding humus to the soil will improve its water retention and workability. With enough water, plants thrive in chalky soils due to their rich nutrient content. However, during summer or hot sunny days, chalky soils dry up easily, which can cause plants to wither and die. The soil's shallowness and high alkaline content can also yield poor plant vegetation.
Plants that Grow and Thrive in Chalky Soil
Several varieties of wildflowers and herbs can grow and thrive in chalky soils. Poppies, cornflowers, cowslips, chamomile, lavender, rosemary and bay are examples of wildflowers and herbs that grow well in chalky soils. Vegetables such as spinach, beets, sweetcorn, and cabbage also do well in chalky soils. Even shrubs like daphne, hibiscus, philadelphus, potentilla, spartium, spiraea, viburnum and weigela can thrive in chalky soils. Trees including arbutus, laburnum, pyrus and sorbus are also suitable choices for your chalky soil garden.
Tips for Growing Acid Loving Plants
Chalky soil can destroy acid-loving plants such as blueberries and magnolias; however, you can add organic matter such as compost or peat to make them suitable for acid-loving plants. Try sedge peat and flowers of sulphur in raised beds, but remember to add a light dressing of flower of sulphur every year to keep the root zone less alkaline.