Salts occur naturally in our local water supplies. Fertilizers also contain salts that accumulate in the soil around landscape plants. High salt levels can damage many kinds of plants. An extra-long irrigation will help reduce salt buildup around plants. (This practice is called leaching.) Leach salts from the soil every six to twelve months by irrigating twice as long as usual. If you live in an area with a high concentration of salts in the water, more frequent leaching may be necessary (perhaps two or three times during the summer and once during the cooler months). A good, long rain that comes at the right time may flush extra salts from the soil and eliminate the need for this activity.