Water use depends on your climate, day to day temperatures, wind, etc. Water when the soil is dry. You can't really prescribe a definite amount of water that's going to work for every location in every weather situation.

No, that is nowhere near enough water down here in the south. In the summary of Mel's book he states:
"The general directions for watering in the SFG are to make sure the soil stays moist...It all depends on the size, season, weather and the growth pattern of that particular plant".

Great advise yolos. When folks hear that SFG saves 90% of water compared to a traditional single row garden they get the idea that they don't have to water as much. They do. The savings is that you don't have to water all the rest of the garden that you'd normally have because your SFG only takes up 20% of the space with 100% of the yield. We have people in our state-a desert-who only try to water twice or 3 times a week. In our city during the summer it's dry enough that my garden is watered twice a day, every day in the summer. Just keep them moist like yolos says and it will be a lot better for you. Good luck and I hope you have better success this year