Cultivating Sweet Potatoes in Iowa's Soil
In Iowa, growing sweet potatoes can be a rewarding experience for gardeners. Here's a guide to help you cultivate these delicious roots successfully.
Sweet potatoes thrive in well-drained, loose, loamy soil that is rich in organic matter. Heavy clay soils are not ideal, and raised beds or large containers with compost-rich potting mix can help if native soil is heavy or compacted.
These warm-season crops need full sun, meaning at least 6 to 8 hours of direct sunlight daily, to develop properly. However, Iowa's climate can be challenging due to its shorter, cooler growing season. To overcome this, start sweet potato slips (sprouts) indoors to extend the season.
Sweet potatoes require a long, warm growing season with warm soil temperatures. The USDA hardiness zones for much of Iowa range between 4 to 5, which is cooler than ideal for sweet potatoes. However, with careful site selection and starting slips indoors early, sweet potatoes can be grown successfully.
Specific cultivar recommendations for Iowa are not detailed, but cultivars that mature early and are cold-hardy or bred for northern climates are preferable. Common sweet potato cultivars suitable for shorter seasons include 'Beauregard,' 'Georgia Jet,' and 'Vardaman.' These cultivars have a relatively short maturity period and good yield.
When it comes to fertilising, applying 1 to 2 pounds of an all-purpose garden fertilizer per 100 square feet before planting and another 1 to 2 pounds at the time of vining is recommended.
Sweet potato plants vine out and trail along the ground, and keeping plantings weed-free early in the season is important. Later in the season, the vining nature of sweet potato will suppress many weeds by itself.
After curing, sweet potato roots should be stored in a dark, cool place with temperatures between 50 to 55°F. Sweet potatoes can be stored under good conditions for four to six months. However, sweet potato roots can become dry and stringy if they are exposed to colder soils for long periods, which reduces root quality and storage life.
It's essential to water regularly, especially during hot, dry periods, but avoid overhead watering to reduce disease risk. Even irrigation throughout most of the growing season is necessary, but limiting water during the last four weeks before harvest can protect the developing roots from cracking.
Finally, it's worth noting that sweet potato and yam are distinct vegetables, with the sweet potato being a dicot (two cotyledons) and the yam being a monocot (single cotyledon).
In summary, for Iowa growers: plant sweet potatoes in full sun, in fertile, well-drained loamy soil, start slips indoors to compensate for the shorter season, and choose early-maturing cultivars suited to cooler climates. Raised beds with rich soil help overcome heavier native soils common in Iowa. Plant sweet potato slips in rows that are 36-48 inches apart, with 12 inches of spacing within the row.
- To maximize success when growing sweet potatoes in Iowa, consider using raised beds or large containers filled with compost-rich potting mix to help with poorly draining native soil.
- Proper site selection, starting sweet potato slips indoors early, and using early-maturing cultivars can help overcome the challenges posed by Iowa's shorter, cooler growing season.
- When fertilizing, an all-purpose garden fertilizer, applied at a rate of 1 to 2 pounds per 100 square feet before planting and at the time of vining, is recommended for sweet potato plants.
- While keeping plantings free of weeds is crucial during the early stages of growth, the vining nature of sweet potato plants can help suppress weeds later in the season.
