Soggy soil can often lead to poor drainage around your property development project. We explore soil types and possible solutions to help deal with the problem
There are several different soil types:
Clay soil is made up of find granules that clump together, making it difficult for water to enter. It expands when its wet and feels lumpy and sticky. It shrinks when its dry and feels rock hard. If drainage is improved, plants grow well as it holds more nutrients than many other soils.
Peat is formed by decomposed organic material, usually found near wetlands. Because it is extremely porous, it too can shrink and expand depending on weather conditions. Peat contains a much higher proportion of organic matter because the soil’s acidic nature inhibits decomposition. This does mean that there are fewer nutrients. It is highly water retentive and may require drainage if the water table is near the surface. Great for plant growth if fertiliser is added.
Sand offers more stability when mixed with gravel as it tends not to retain water. Gritty to the touch, and as it is free-draining, it can dry out rapidly. Easy to cultivate but nutrients tend to be easily washed through the soil in wet weather.
Silt is well-drained soil which is smooth to the touch. Although easy to cultivate and work, light sandy soils dry out quickly and are low in nutrients It retains moisture well and is richer in nutrients than sandy soil. Easier to cultivate than clay, but soil structure is weak and easily compacted.
Acid is usually stony, therefore free-draining. Often overlays chalk or limestone bedrock which means deficiency of some minerals, such as manganese and iron, causing poor growth and yellowing of leaves.
Loam is a perfect soil. A combination of sand, silt, and clay, it handles moisture in a balanced way. Drains well, retains moisture, full of nutrients and easy to cultivate. Warms up quickly in spring and doesn’t dry out in summer.
If the ground around your property is damp or swampy, it is usually because of poor drainage. There are a several ways in which the problem can be dealt with:
Digging trenches under the topsoil and filling them with aggregate will allow water to drain more easily. However, if you are planning a major trench installation, it may be advisable to consult an expert, as extensive digging could have an impact on your property’s structural stability.
If your site is reasonably flat, then sub-surface trenches are relatively easy to install. Water can be redirected to nearby dry areas, sump pits or storm-water drains. It will be necessary to obtain council approval for the latter. Any drains that you create should not empty directly into sewers or neighbouring properties and, of course, should not interfere with utilities such as gas, phone or power lines.
If your soil is heavy, try adding materials like gypsum or clay breaker, which opens up the structure of the soil and allows water to penetrate. It can then be further improved with the addition of well-rotted compost. Plants are more likely to thrive, which will continue to add organic matter, slow down water transfer and continually improve the soil structure.
Most plants don’t do well in soggy soil, and few will survive long spells of flooding or waterlogged conditions. Excessive moisture results in rot and other deadly diseases. However, there are some plants that are tolerant to wet conditions and so can be grown successfully, such as Hydrangea, Hosta, Marsh Marigold, Snowdrops, Sedge, Cotoneaster, Foxglove, Cattail, Day Lily, Lilies of the Valley.
Plants that can withstand long periods of soggy roots and thrive around garden ponds are Water Hyssop, Pickerelweed, Cattail, Iris, Swamp Sunflowers, Scarlet Swamp Hibiscus. Many ferns tolerate wet areas and also thrive at the edge of ponds, including Cinnamon, and many fern varieties such as Sensitive, Royal, Marsh and Holly.
Soil improvement, better drainage and careful selection of moisture-loving plants will all help to keep down the water levels in your soil. If, however, your property sits on water-starved ground, then you might want to read the next blog!