Soil that best for Sweet Potatoes

Sweet potatoes grow best in light, sandy soils but grow well on heavier soils, high in clay and amended with organic matter. Full sun requires direct light at least 6 hours/day; prefers 8 - 10 hours/day. Days to maturity: 85 - 120. Spacing: 12" in-rows x 40" between row.

What is the best fertilizer for sweet potatoes?

Sweet potato vines thrive best when a balanced slow-release 10-10-10 or 12-12-12 fertilizer is applied.

I highly suggest you would mix top soils with any dried leaf, mulches and cow/chicken manures (bought at Home Depot or Lowes , around $2-$3/bag). Sweet potatoes will produce high yields with this kind of mix soils.