Soils are often categorised as sandy, silty or clay, although there are other varieties too. To find put which type you have, simply rub a small amount between your fingers. If it’s smooth, it’s silt. If it can be rolled into a ball it’s clay and if it’s gritty, it’s sandy.
Types of Soil
Each type of soil has its benefits. Silty soil is the most fertile and lots of plants flourish in it. Sandy soil warms up quickly during the summer months which aids plant growth but during extremely hot periods, it dries out quickly so you need to be careful with plants that consume a lot of water. Clay soil retains moisture well and tends to be colder to the touch.
Roses tend to thrive in clay soil and lavender and marigolds do better in sandy soil. However, it’s not simply the type of soil that will cause a plant or flower to thrive or wither but also how acid or alkaline the soil is. This can be easily measured by a pH testing kit which you can obtain from your local garden centre. It basically involves taking a small sample of soil and adding water. The test kit is then exposed to the wet soil and if it turns yellowy-orange it’s acid soil, green is neutral and dark green indicates it’s alkaline soil you’re dealing with.
pH and How it Affects Soil and Plant Growth
Knowing the pH value of your soil before planting is crucial as it has a direct effect on the health of the plant. Each plant has its own recommended pH value range and these are usually marked on the seed packets or plant pot. The reason being is that the soil pH affects the availability of nutrients within the soil and plants have different nutrient needs.
A pH of 7 indicates neutral so a pH of less than that indicates acid soil and a pH of 8 or above is alkaline soil. Acid soil is great for things like camellias, rhododendrons, magnolias and azaleas but wallflowers and members of the cabbage family won’t approve. Clematis, lilacs and hypericum belong to the family of plants which prefer alkaline soil.
Changing the pH of the Soil
If you’re not happy with the types of flowers and plants which suit your soil type, then you can artificially alter the pH to turn acid soil into alkaline and vice versa.
To make it more alkaline, you need to add a form of limestone. The smaller the particles, the quicker the result which is why hydrated lime offers the quickest performance. Equally, to make your soil more acidic, sulphur or aluminium sulphate can be used. Sulphur is more reliable but can take longer whilst aluminium sulphate is the quickest acting but its effects can be short term and it’s possible to over apply it. Two to three months minimum is usually recommended when trying to convert your soil pH but a good garden centre will be able to advise you what to do.
Therefore, care with regards to the types of plants and flowers you choose should be taken against the type of soil you have and its pH value. If you follow these guidelines, your garden should flourish.