Boron can also be elevated in incoming water and should ideally be kept below 0.6 ppm. Plants exhibit a wide range of tolerance to salinity and specific ions. Growers take advantage of this by grouping plant material in the nursery according to relative salt tolerance. Sensitive plants including liners, azaleas, camellias, ferns and many deciduous plants are located in a portion of the nursery which does not utilize recycled water. Annual color or herbaceous crops along with many common ornamentals have a moderate level of salt tolerance once established and can be grown with water of moderate salinity.
Some crops are very salt tolerant and can be irrigated with non-blended runoff.
Where sodium and chloride toxicity is of concern, development of leaf burn can be minimized by utilizing drip-irrigation or by irrigating at night to reduce foliar deposition of salts. Salinity and nutrient levels should be routinely monitored in container soils. Large nurseries often have an in-house program of routine sampling and analysis for ECe and occasionally for pH and extractable nitrate and potassium. Samples should periodically be sent to a reputable laboratory to carry out more complete nutrient and soluble salt analysis and to check the accuracy of in-house determinations. Leaf analysis can also be used as a tool to monitor nutrient and specific ion status.