Soil feel test . A shovel, soil auger, or push tube can be used to obtain soil samples. Samples should be taken from a depth of 8 to 9 inches to the bottom of the effective rootzone. Squeeze the soil between the thumb and index finger to form a ribbon. Soil type and the grower's experience will indicate the relative amount of moisture in the soil.
Tensiometers give a direct reading of the soil moisture tension existing in the rootzone.
These instruments should be placed in strategic locations within the plant root- and wetted zone. Depending on the plant's maximum rooting depth and soil type, more than one tensiometer may be required per site. For example, one might be placed at a depth of 12 inches and another at a depth of 30 inches. These should be located just at the inner edge of the normal wetted area. Tensiometers require frequent supervision and must be correctly installed and serviced in order to obtain reliable results.