If your garden is well established, has well-draining soil or has had drainage put in already, then additional work may not be necessary. But if you find soggy patches that just won’t go away, you may need to consider installing drains.
New housing estates often need drains putting in after contractors have left. The constant compacting of the earth by diggers and trucks, and the likelihood that they will have left bricks and rubble under the top soil, mean that these gardens don’t get the best start in life. The mixing of sub-soil and top soil from the digging of trenches and foundations adds to the problem.
Other problems come from clay soils and sometimes, when new houses are built on former arable land, a “plough pan” may exist below the ground. These are formed just below the level that the plough reached and become impervious due to the constant ‘polishing’ of that surface by the machinery.
Test the quality of your garden’s drainage by digging a hole of around 600mm x 300mm and fill it just half full with water. If after a day it has drained, then you don’t need extra drains, but if it retains some water or even fills up, then you do. The hole may actually gain water if you are in an area where the water table is low.
So what is the answer? Sometimes simply replacing or digging organic materials into the top soil can help, particularly if it is dense and clay-ridden, though this may mean a lot of work over a long time and is not really suitable for lawns.
For some gardens, digging ditches around shaped garden surfaces can relieve the problem.
A soakaway is a more powerful alternative. By digging quite a large hole in the lowest part of the garden that is about 1.8 m (6 feet) square, and filling the lower part with bricks and rubble and the top part with soil, it creates a place for water to drain away. You may or may not need pipes according to the gradient of your lawn, but if you do then clay or plastic pipes can be installed to assist drainage.
Gabriel Ash recommends that, if you are considering having a greenhouse erected, you have any drainage work done well in advance. You will need to establish a nice, firm level plot on which to build. Do ring and ask our experts, if you need advice.
Advice on how to install lawn drainage can be found at http://www.gardenadvice.co.uk/howto/lawns/drainage/index.html