Growing Sweet Potatoes in a Cold Temperate Climate: Our Approach

Growing sweet potatoes in a cold temperate climate, like Central New York, requires careful planning and specific techniques to ensure a successful harvest, given that sweet potatoes thrive in warm, long growing seasons.

Selecting Starter Plants at Harvest

In the fall, when we harvest our sweet potatoes, we take the opportunity to prepare for the next growing season. Instead of using the traditional method of starting slips indoors, we focus on selecting strong starter plants. As we remove the sweet potatoes from the roots, we cut back the vines, leaving a couple of nodes on each vine. These cut-back vines are then potted in soil and kept under lights throughout the winter.

Winter Care

The overwintered starter plants require consistent care. They are kept under grow lights to ensure the plants stay healthy and develop throughout the colder months. By keeping them in pots indoors, we protect them from the harsh winter conditions outside while allowing them to build strength for the next season.

Spring Pruning and Rooting

As spring approaches, we prune the vines back, encouraging stronger growth. The cuttings from the vines are easily rooted in water for about two weeks before planting them in the garden. These rooted cuttings become our slips for the new season.

Benefits of Overwintering Mother Plants

The plants that we overwinter and nurture indoors tend to produce the largest and most productive sweet potatoes. By using mother plants instead of starting new slips from scratch each year, we see a significant improvement in the size and quality of our harvest. These mother plants have already developed strong roots and are better adapted to the growing environment, giving them a head start when planted outdoors in late spring.

Preparing the Soil and Planting

We prepare our soil by incorporating compost and organic matter into our permanently raised beds. Sweet potatoes prefer well-drained, loose soil, which helps the roots develop without any restrictions. Once the soil is ready and the danger of frost has passed, we plant the slips from our overwintered mother plants in the garden.

Cover Cropping

After we harvest our sweet potatoes in the fall, we plant winter rye as a cover crop to protect and enrich the soil over winter. This helps prevent erosion and improves soil fertility for the next growing season.

Composting the Vines

We compost all the sweet potato vines that we cut back during harvest. These vines break down over time and help to create rich, fertile soil that we use for future plantings, completing the cycle of growing sweet potatoes.

By selecting starter plants from the fall harvest, overwintering them indoors, and using cuttings in the spring, we ensure a continuous, productive cycle for sweet potatoes, even in a cold temperate climate.