I’m new to container gardening, and I’m having watering issues. I’m using 55 gallon food grade barrels for vegetable gardening; self-watering containers. They have an overflow tube about 6” from the bottom of the containers, and the fill tube is on top. I have to almost completely refill the containers every two days, and my soil is staying so dry that it’s pulling from the sides of container. I’ve tried wheat straw for mulch or white plastic; neither seem to work as needed. My plants are staying stressed out and not producing a lot…one day a plant looks excellent, next day dead. Georgia’s high temps are just zapping all moisture from the barrels and I’m desperate for info to help me figure it out. Ideally, I should only have to top off the barrels once a week, especially in the summer, but I must be do something incorrectly; just baffles me.