Just put the turtle in the same spot the blue wool is in the picture. It is hard to get used to but once you do, it becomes habit.
Pictures:
Spoiler
Pastebin Code:
pastebin get jexkZWTC Farm
Spoiler
A few notes about the code:
-The turtle doesn't know when the wheat is fully grown or not so when it is time to harvest nothing is safe.
-The turtle is on a timer of 80 minuets between harvests.
-Fuel the turtle before using the program, I haven't added an auto refill.
-You may want to run the code a few times so you can find the best spots to put the water, as you can see just eyeballing it in the picture did not work out.