Moisture Sensor Tested in Soil: Success!

Before today, we had only tested the leads in air (touching and not touching). Today we tested the moisture sensor in soil with varying degrees of water added. The test confirmed that the system is functional. The values that we obtain from the arduino (via serial) are as follows:

In air, not touching: ~0
In air, touching: ~1023
In soil,
--very wet: ~900
--optimal: 700-800
--needs water: ~650
--definitely needs water: <625

Leads (moisture sensor) in soil.

Python code to do something with the values read from serial is given below:
#import libraries
import serial
import math

#open serial communication
arduino = serial.Serial('/dev/ttyACM0', 9600)

if serial.Serial.inWaiting >= 5:
#control corresponds to 100% light transmittance (in absence of any #petri dish); each respective sample reading corresponds to the light #transmittance through that petri dish.
    val1       = float(arduino.readline())
    val2       = float(arduino.readline())
    val3       = float(arduino.readline())
    val4       = float(arduino.readline())
    val5       = float(arduino.readline())

#calculate soil moisture reading
moistureValue = float((val1 + val2 + val3 + val4 + val5)/5)

if moistureValue < 625:
    print("omg so thirsty so thirsty need water")
elif moistureValue > 625 and moistureValue < 700:
    print("I'm starting to get thirsty")
elif moistureValue > 700 and moistureValue < 800:
    print("I feel so hydrated!")
elif moistureValue > 800:
    print("Gross, I feel bloated")

#print out absorbance values in neat table     
print "moisture value: " + str(moistureValue)