If sandy soil works I should be able to grow hot ones where I live , Sand Mountain known for it's sandy loam soil . According to this article hot weather is what you need , does it get hot in Texas ? https://balconygardenweb.com/how-to-make-pepper-plants-hotter-steps-to-spicy-chillies/Interesting. It doesn't come much blacker than the montmorillonite clay of N. Texas. I till in a lot of compost to make it fertile. Next year, I'll try a pot of sandy soil. Might work.