where did read Mels mix is not good for sweet potatoes.
sweet potatoes should be planted 18 inches apart.

I would comment more but since you have not cited your sources. I can not check the underlying support of the sources.

http://lrrd.org/lrrd19/3/olor19036.htm
here is the study regarding cutting leaves too often and the effects on root development.

As for MMs mix, my concern(from many posts and peoples past experiences)is that overly nutritious soil will grow long stringy roots and produce too much foliage(haven't found studies on this). Many people state that the closer to sandy loam and poor soil quality tends to grow larger sized sweet potato. by many people i would say a consensus on the internet. Another issue is that MM maintains moisture very well and too much moisture also affects sweet potato growth and may even cause rot.

I have plenty of homemade compost to add to the box if necessary. My other MM plants are doing amazing. My garden is only 1 and a half months old and I am picking radishes, peppers, cucumbers and tomatoes are ripening on the vines.

I am in Houston TX where it usually rains a ton. This year however it hasn't rained since february or so.

hope this info helps. thanks for your interest and help.

I'm in the Houston area also and planted Vardeman so I wouldn't have to trim back. Planted many of them 12" apart. Am just planting the slips in various areas of the garden, no box.

hi lucille,

I know i want to vardemans next year. keep this post alive with pictures if at all possible. I didn't realize that i should have done vardeman until I finally succeeded at growing my own slips. I'd love to see how your garden progresses.

did you grow your slips(if so how did you find the potato) or order them? what kind of soil, plain old houston dirt, amended, or compost amended? I'll post the pics once my slips are in this week of the store bought sweet potatoes.

I found a small family owned sweet tater business (they are still mailing out btw) The sips arrived very fresh and they sent extras. This is the first year I ordered Vardemans, what with grocery prices rising I'm trying to make the most of my space and I'm already growing vining melons and they are space grabbers.
I've had my current garden for nearly 30 years, I started out with bought soil but now that I'm older I just amend with leaves and stuff in the fall. It is raised a bit. The sweet taters are just planted here and there, and not near any of the roses,perennials, grapevines or trees, places I wouldn't want to dig.

Here is a link that might be useful: George's sweet taters