Sugar baby watermelons

My family loves watermelon! But you might be surprised to know that watermelon is more than just a sweet watery summer treat. Watermelon contains the largest known source of lycopene, even more than tomatoes, as well as a healthy dose of Vitamins A, C, and B6.  These nutrients may provide protection from prostate cancer as well as boost your immunity, dental, vision, and brain healthy. This is my second year to attempt growing my own in the form of the icebox variety sugar baby. Last year I purchased one plant on a whim, it never did we'll and I thought it was due to late planting. This year I selected three very healthy plants, but while remaining healthy they are not growing at all. Upon doing some research I discovered that this variety loves hot weather, here in Texas we have plenty of that, so my next guess after reading they are heavy feeders, is that my soil must not be sufficient. I found an online tip about using almost ready compost to provide both heat and nutrients. Since my plants are already in ground I had to modify a bit. I dug the soil from around each plant, put in the compost and covered with the displaced soil. I am trying to use as little commercial product as possible, but if no results from this experiment in 1-2 weeks then I will use some fertilizer.