Excessive drainage in sandy soil can be an annoyance, you need to water regularly in dry weather and it is necessary to build up a water-holding structure by adding as much organic matter as you possibly can. Faulty drainage is a lot more than just a nuisance, it can be a plant killer. Stagnant water laying around the roots starves them of air.
Helpful bacterial activity is slowed down and harmful organisms flourish. Toxic gases build up and the overall result's are poor growth at first and then the eventual death of the plants if conditions don't improve.
Poor drainage is caused by heavy topsoil. Water moves very slowly through clay, so the solution is to improve the structure by cultural means. impeded drainage is a more major problem, because the downward movement of water is not just slowed down - it is blocked.
There are actually three prime causes:
Non-porous rock below the soil, a sub-surface pan below the topsoil or a high water table in the area (the level at which porous rock is saturated with water). Soils with blocked drainage are waterlogged for long periods during the winter months, so some remedial action is vital.
Either of the following methods mentioned below could potentially solve your dilemma. It all depends on what problem that you find yourself having to face along with the type of soil you have.
Poor drainage caused by a higher clay content in the topsoil can be improved by double digging in the autumn. On no account should the rough clods be broken Up at the time of digging - leave them to be crumbled by the action of wind and frost during the winter months.
Double digging can also break up a thin soil pan therefore permitting water to drain through. Occasionally the sub-surface pan is too thick to be penetrated with a normal garden fork, instead use a pickaxe or steel bar and sledgehammer. In rare the pan can't be broken. You will probably then need to use an artificial drainage system or else raise the level with brought-in-soil.
The crumbs created by digging provide temporary relief, but you need to build up a permanent crumb structure by adding heavy dressings of organic matter at regular intervals. Add calcium in the form of lime or chalk if the soil is acid - use gypsum if it is neutral or alkaline.
If the causes of poor drainage is either non-porous rock close to the surface or an abnormally high water table, a man-made aid will likely be recommended. Laying drains is an expensive, backbreaking and time consuming job, it is often better to tackle the problem by raising the soil level. Buy good quality topsoil and add it to the entire surface if the garden is small or use it to fill raised beds.
A tile drainage system consists of a herringbone pattern of plastic or earthen ware tile drains. A rubble drainage system is made in the same way, however the drain pipes are left out.