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Eggplants, peppers, and tomatoes require regular, uniform watering during the growing season. Inconsistent water availability can cause several problems including poor early vigor, inadequate leaf cover, flower drop, sunburn, blossom end rot and fruit cracking. For this reason, drip irrigation is well-suited for production of these plants. Water deeply and infrequently to encourage deeper root growth. As temperatures increase and plants grow, irrigation rates should be increased to meet plant needs. A small decrease in water after fruits reach mature size is beneficial in that it can trigger fruit ripening. Soil water status should be monitored regularly to maintain consistent soil water. This is easily done with a resistance block such as the Irrometer Watermark sensor. Place sensors at various locations in the field and depths in the soil profile to get a more accurate measurement of soil water content. Sensors typically express soil water content as a tension reading (centibars) that defines the resistance in the plant to access available water. Soil texture (clay, loam, sand) influences the soil’s ability to hold water. Field capacity describes a soil at 100 percent available water holding capacity after excess water has drained away. Start drip irrigation at 20-25% depletion of available water holding capacity depending on your soil type (Table 9.4). Other low cost tools and methods to monitor soil water can be found at

Table 9.4. Soil tension values for different soil textures for use in scheduling drip irrigation.

Soil Texture 0% Depletion of Available Water Holding Capacity (Field Capacity)
Soil Tension Values (in centibars)
20-25% Depletion of Available Water Holding Capacity
Soil Tension Values (in centibars)
Sand, loamy sand 5-10 17-22
Sandy loam 10-20 22-27
Loam, silt loam 15-25 25-30
Clay loam, clay 20-40 35-45