Just how low is your water table, anyway? (Height of an actual table, maybe? Isn't some of that area below sea level?)
The floor of my house is higher than sea level. The ground below my house is ever so slightly above sea level (we're on a ridge!).
How is your RH throughout the day and night there?
Temp/RH data for 1 week.
Here's the probe data from the veg tent...
The other probe is the interior of the shed. This basically represents the local temps in the sun.
Hmmm.... perhaps I shouldn't fill this thread with all this.