- 1). Find a spot below the level of the garden where the water can drain away safely. A storm drain, dry well or drainage ditch is an ideal choice.
- 2). Measure the distance from the lowest point in the problem site to the drainage area. Then buy enough perforated 4-inch (10-cm)- diameter pipe to cover that distance. (Either black ADS or white PVC pipe will work fine.)
- 3). Dig a trench 18 inches (45 cm) deep and 12 inches (30 cm) wide, sloping downhill between the two points. Try for a drop of about 1 inch (2.5 cm) for every 10 feet (3 m) of ground.
- 4
Test the slope by driving a stake into the soil at each end of the trench. Run a string between the two stakes, and use a spirit level to measure the drop between them (see A). - 5). When the slope is at the correct angle, line the trench with about 3 inches (7.5 cm) of gravel or crushed stone.
- 6
Lay the pipe on the stone (see B), and make sure any joints are fastened tightly. - 7). Cover the pipe with agricultural fabric to prevent soil from clogging the perforations (tuck the cloth under the pipe at its uphill opening).
- 8). Add 6 more inches (15 cm) of stone over the pipe.
- 9). Replace the soil in the trench.
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