Ive been looking at using epoxy putty to make a sealed waterproof area around a soil moisture sensor so that the water doesn't seep through the gaps between the sensor and the hole its sticking out of would this effect the sensor??
We don't know if it would affect the sensor, because we don't know what the sensor is.
(How is this an installation and troubleshooting issue?)
if you are talking about a capactive sensor and putting an enclosure over the electronical bits, then, YES, it will effect the sensor.
DO also use nailpolish to seal the edges of the raw PCB.
as for if it will effect OPERATIONAL USE ?, NO.
the initial setup allows for a condition (sealant) to be part of the board and will remain unchanged for the life of the sensor.
only things that will vary to effect(alter) readings will have influence on operation.
so, once installed, only water would influence the variable readings.
as a note, if you used thinner PCB or different width traces, or any other change, it would effect the sensor, and in the same way, the initial setup allows for constants.
I used hot glue on low heat to make my cap moisture sensor water resistant. They have been running for 1.5 years so far without issue.