After fighting with the SD card code for two weeks (when they say it only works with <2GB they mean the card type on the partition size. Only had a 4GB card so formatted it to a 1Gb partition and still did not work. Turns out the way the guts of the SD card work changes over 2GB) I finally have a setup that takes readings every 15 minutes and logs them to a SD card. Also added a small chunk of code to cycle the RGB led to the next of 7 colors on every reading as a status indicator. Right now the hardest part is not watering my sensor. If the reading make sense and look good after a week or two I am going to pot the sensor in epoxy.
Unfortunately not able to finish the project in time for the competition but over the hill now. Just need to add the input multiplexer and the pump control. Will continue to work on it as time allows.