Sunlight: Full sun
Maturity: 70-140 days
Height: 1 to 3 feet
Spacing: 12 to 18 inches apart, 3 to 4 feet between rows
Native to Central and South America, the sweet potato is an important food crop in tropical and subtropical countries. Here in the United States, home gardeners growing sweet potatoes require a long frost-free season to mature large, useful roots.
Fun fact: More than 40% of the national supply of this edible root comes from North Carolina.
- Requires very warm temps and a long growing season
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- Plant into loose soil that drains easily; give them full sun and plenty of room to spread out
- Only plant after soil has warmed and all danger of frost has passed
- Ready to harvest in 70-140 days
- Eat only after curing, which develops a protective skin, then storing for several weeks
- Pests and diseases include alternaria leaf spot, fusarium root and stem rot, sweet potato stem borer, and mice.
If you’re looking for the fastest ticket to a lush garden, start at ground level. Planet Natural offers a large selection of amendments, potting soils, inoculants and testing kits to help you produce healthy, productive plants year after year.
Sweet potatoes are not truly potatoes, but a thick root of a tropical vine. They need full sun, well-drained soil (preferably sandy loam) and plenty of room to thrive. Sweet potatoes are not heavy feeders, but they do require a good balance of nitrogen, potassium and phosphorous. Work in a low nitrogen organic fertilizer before planting; too much nitrogen produces leafy growth at the expense of the roots.
How to Plant
Plant in late spring when soil temperatures have warmed to 70 degrees. In colder climates, get a jump on the season by heating up the soil with clear plastic, which allows sunlight to heat the soil below.
Set root-bearing stems, called slips, 1 foot apart in rows spaced 3 feet apart. In raised beds, space plants 1-1/2 feet apart. Soak slips in compost tea for five minutes prior to planting to help reduce disease problems. Use Harvest Guard® row covers to add extra heat and keep out pests.
Harvest before frost, after foliage starts to yellow, about 70-140 days after planting. Dig tubers as you would potatoes, using a garden fork to gently loosen soil and release the sweet potatoes. Use any damaged potatoes as soon as possible, but remember that full flavor only develops over time — fresh sweet potatoes are bland. Cure healthy potatoes for two weeks in a warm place.
Insects and Diseases
Sweet potatoes are subject to several types of fungus, which can damage leaves and tubers. Alternaria leaf spot appears on older leaves and has a target-like appearance. Fusarium root and stem rot damages the base of stem and the interior of the potatoes. If you see stunted plants, dropped leaves and large black spots on the tubers, you’re probably dealing with black rot.
Common insect problems include sweet potato stem borer, which can be identified by wilting leaves and holes on the stem, and white grub, which feed on the underground roots and stem.
To prevent diseases, plant varieties with multiple resistance, use certified plants and rotate sweet potatoes’ location in the garden. Rodents and mice may become a problem, as they burrow into the mounds and eat the nutritious roots.
Seed Saving Instructions
Sweet potatoes are perennial vines that are propagated vegetatively, either by shoots or from tubers. They are not grown from seed.
The same great Pro-Biotic formula with beneficial soil microbes and mycorrhizae.
Floating row covers let in sun, water and air... but keep bugs out! Protects to 26°F.
Made from a select blend of plant materials plus seaweed and rock powders.