What size auger bit should I use when installing root tubes for use with the CI-600/602?

For the CI-600 In-Situ Root Imager, we recommend a 3” (inch) diameter auger bit with two extension pieces for drilling holes to accommodate the 2.75” outer diameter of the CI-600 tubes.

For the CI-602 Narrow Gauge Root Imager, a 2.5" auger bit with two extension pieces is recommended for the 2.25" outer diameter of the 105 cm length CI-602 tubes.

When using the earthquake auger, brace the auger to steady the bit and to ensure that the angle of the holes for each tube placement is consistent.The hole created by the auger should be just larger than the tube to minimize the airspace around the tube exterior. With excess space, created by an unsteady auger bit, air pockets can occur between the tube and the soil, which will be visible in the root image and may lead to excess condensation on the exterior of the root tube. It is best to limit the space between tube exterior and soil wall to 8mm, or 0.3".