Sweet potatoes like it HOT and dry, FULL sun all day. The don't seem to care how bad the soil is but they do better with good soil, fertilizer and water. If you plant more than 1 plant make sure you plant them 3 feet apart. You can make the vines grow in straight rows both directions from center OR make the vines grow in a circle around the mother plants. I usually plant 1 plant in the center of a 50 foot row but this year I have 2 plants, I am making the vines grow around and around the mother plant the circle gets larger each time the vines circle the plant. Soon the circles will be 20 feet diameter each. I cover the vines with dirt as they grow this makes the vines sprout root and grow more potatoes at each satellite location. 1 plant can make 50 lbs of potatoes. I have not watered my plants this year because we have been getting too much rain. I fertilized the potatoes several times with wood ash and1 time with a very small amount of 15/15/15 fertilizer. I expect to have very close to 100 lbs of sweet potatoes from these 2 plants but just have to wait and see my plants are getting full shade from 12 noon to dark so that may reduce my potato crop this year. TX soil is a lot like AZ soil you may need to add lime or wood ash.