DAVIS Leaf & Soil Moisture/Temperature Station for Vantage Pro - Manual (Page 17)

Installing Soil Moisture & Temperature Sensors Page 17
CAUTION: In gravelly soils and with deeper sensors, carefully install the sensor to pre-
vent damaging the membrane.
• Lack of a snug fit is the biggest problem in
obtaining good soil moisture sensor read-
ings.
• The ideal way of making the access hole is to
use a stepped installation tool. The stepped
tool makes an oversize hole for the upper
portion and an exact sized hole at the bottom
where the sensor is located.
• The illustration to the right shows the
dimensions required to make a stepped
installation tool.
4. After installing the soil moisture sensor the hole
needs to be carefully backfilled and tamped
down. This prevents the creation of air pockets
which could allow water to channel down to the
sensor.
• Fill the hole with water and push the sensor
down into the hole so it bottoms out.
A length of 1/2” Class 315 PVC tubing fits
snugly over the sensor collar and can be
used to push the sensor. A good snug fit in the soil is important.
• Carefully backfill the access hole with soil to eliminate any air pockets.
5. You can solvent weld the 1/2” Class 315
PVC tubing to the sensor collar for easier
installation and removal.
• Use a PVC/ABS cement (IPS Weld-on
#794 or equivalent).
6. After you have installed the soil moisture
sensors, the sensors will need one or two
irrigation cycles to “break-in” and accli-
mate to the soil conditions and provide bet-
ter accuracy.
Installation Procedure for Turf/Lawns
1. Cut a slight “V” shaped trench about 5”
wide at the top and about 6” deep into the
turf--about 6” long.
2. Lift out the turf plug piece you just cut.
Home-Made Stepped Sensor
Installation Tool
2-1/2" (64 mm)
7/8" (22.5 mm)
Cold rolled steel,
round rod
1-1/4" (32 mm)
approximate
diameter
Overall length
variable
Sensor
Wires
Tape
1/2" PVC Pipe
Pipe welded to
sensor collar with
PVC/ABS cement
Soil Moisture
Sensor
PVC Pipe Welded to Soil Moisture
Sensor Collar