Do you have them in full sun Christi?
Al's Mix Recipe should do well for you with some Miracle Grow mixed in. Also in your harsh summer sun they should maybe get morning sun only, or filtered sun.
Try getting another plant from your local Home Depot or Lowes, they have had some really nice ones this year at very reasonable prices.
Mix up Al's recipe with maybe 1/3 MG added to the mix. Give the plant some protection from harsh sun and heat. Only water if the top inch or so of mix is dry.
Just do the one plant until you figure out what will work in your area of the country.
Let me know how it goes. Once you figure out soil, light and water you will never have problems growing them again.