Excessive levels of these essential nutrients can damage or destroy a plant. In fact, the most common cause of soluble salt damage is overfertilization. The risk of such problems in nursery crops is particularly acute because potting media can be low in essential nutrients and thus require significant fertilizer amendments.
Critical levels vary depending on the salt, the plant species, the growth stage and the climate.
Warning symptoms include reduced germination, stunted growth, leaf burn or chlorosis of new growth. Table 1 presents a partial list of plants sensitive to high soluble salt levels. Azalea, rhododendron, and photinia are among the most salt-sensitive plants. They will often show symptoms before other nursery plants. Measuring, interpreting and controlling soluble salts in the soil solution are among the keys to a successful nursery.