One of the greatest drawbacks to successful gardening is badly drained ground. Wherever water lies in the ground at a depth easily reached by the roots of most cultivated plants they do not thrive, except where the water is constantly on the move, such as the bank of a river, brook or lake; there many plants will flourish. There are some wild plants that succeed in soil that has reached a water logged state, but generally such land is useless for gardening, farming or forestry purposes unless steps are taken to free it from superfluous moisture.
Heavy clayey land or soil overlying a hard subsoil is very subject to water logging; so, too, is low-lying land which is little above the high water mark of a river or lake in the vicinity.
When undertaking drainage operations, it is necessary, first, to find whether there is a natural fall from the land in question to a brook, river, lake or pond in the vicinity, and the gradient of the fall. As a rule, it is wise to lay one or more main drains with which side branch drains, laid in herringbone fashion, are connected at such intervals as are likely to carry off the superfluous moisture. The main drains will need to be about 21/2 or 3 ft. beneath the surface, with a slight fall to the outlet; the branch drains may start 15-18 in. deep and fall gradually.
For the main drains, agricultural drain tiles 6 in. in diameter with open joints will usually suffice, the side drains being of similar tiles 4 in. in diameter. The pipes should be laid on an even, gently sloping bottom and around them and over them a layer of loose rubble, gravel or cinders should be placed. In woodlands a series of open drains or ditches answers better than drain-tiles, but the ditches should be cleaned annually.
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