How often should you water Green Onions? [ in June, July, August]?

Question:O.k. My mom has a box garden on our back porch. Her Green onions that she had planed, grew just fine, but when she pulled them, the Onions were soft. Is this cause from to much water?! And if so[or not] how often should you water Green Onions?!

Answers:
Go to the nursey department of any hardware store and get a water meter. They cost about five bucks. You stick the probe in the soil and it instantly tells you if it is wet or dry. Works great and save water and guessing.