🍠 Sweet Potato

Ipomoea batatas
A morning glory that decided to store sunshine underground — and Florida's favorite overachiever.
Sun
Full sun, 8+ hours; heat is not optional, it's the whole point
Days to harvest
90–120 days from slips
Spacing
12 inches apart in rows 3 feet apart, on ridges or mounds 8 inches high
Soil pH
5.5–6.5 (tolerates acidic soil better than almost any crop)

How to grow

Sweet potatoes don't grow from seeds or tubers — they grow from slips, which are sprouts grown from a mature root. You can make your own by suspending a sweet potato in water or laying it in moist soil 6 weeks before planting time, but buying certified disease-free slips is easier and safer. Plant slips deep (up to the top leaves) in warm soil — at least 65°F, and warmer is better. In Florida, that's April through June; up north, wait until nights are reliably above 55°F.

Then comes the hard part: doing nothing. Sweet potato vines sprawl 10+ feet and root wherever they touch soil, and every bit of fussing reduces the harvest. Don't prune the vines, don't hill them like regular potatoes, and definitely don't fertilize heavily — excess nitrogen grows a jungle of leaves and skinny, disappointing roots. They actually yield better in poor-ish soil, which makes them the rare crop that rewards neglect.

The storage roots form near the original slip, swelling through late summer and fall. They need the full season — yank them early and you get sad, skinny roots with no sweetness, because the sugars develop late.

Water & feeding

Water well for the first few weeks to establish slips, then back off — about an inch a week is plenty, and established plants tolerate drought. Stop watering 2–3 weeks before harvest so skins toughen. A modest amount of worm castings at planting is plenty; heavy feeding backfires on this crop.

Common problems

  • Root-knot nematodes (lumpy, deformed roots — common in Florida sand): rotate crops, solarize soil in summer, choose resistant varieties like 'Beauregard'.
  • Sweet potato weevils: use certified slips, destroy crop residue, rotate; the weevils overwinter in leftover roots.
  • Deer and rodents: the vines are candy to wildlife — fencing is the only real answer.
  • Cracking: inconsistent water late in the season; keep moisture even once roots start bulking.

Harvest

Dig before first frost (or when vines yellow in frost-free areas), being careful — the skins are paper-thin at harvest. Then CURE: 80–85°F and high humidity for 7–10 days. Curing converts starches to sugars and heals skin nicks; uncured sweet potatoes taste starchy and rot fast. Cured ones keep for months.

Nerdy fact: Sweet potatoes are in the morning glory family (Convolvulaceae), not the potato family — they're more closely related to the pretty vine on your fence than to a russet. And that 'yam' at Thanksgiving? Almost certainly a sweet potato. True yams (Dioscorea) are a completely different plant, mostly grown in Africa.

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