Growing, Harvesting, and Planting Sweet Potatoes in a Zone 5 Cold Temperate Climate
Growing sweet potatoes in Zone 5 cold temperate climate can be a rewarding endeavor, yielding delicious and nutritious tubers even in cooler regions. Here’s how we successfully grow, harvest, and plant sweet potato plants each year, ensuring a bountiful harvest despite the challenges of a shorter growing season.
Growing Sweet Potatoes
Starting the Sweet Potato Plants:
Storage: After harvesting sweet potatoes in the fall, we remove the tubers from the roots and prune the vines back to two leaves from the root crown. The sweet potato roots are then potted up into 1-gallon pots with garden soil and stored in our house over the winter.
Winter Care: The stored roots are planted in pots and cared for like any other houseplant. This includes regular watering and placing them under a fluorescent light that is on from sunrise until sunset. We do not fertilize the plants during the winter.
Pre-Planting Preparation:
Cutting and Rooting: A few weeks before planting time in the spring, we cut multiple sections (about two dozen) from the stored sweet potato vines. These cuttings are placed in jars of water to develop roots. By the time it’s warm enough to plant, the vine cuttings are well-rooted and ready for transplanting.
Planting Sweet Potatoes
When to Plant:
We wait until the evening temperatures consistently stay above 45°F (7°C). In our Zone 5 climate, this typically means planting in late spring.
Preparing the Beds:
Our permanent raised beds are prepared by ensuring they are rich in organic matter and well-drained. Sweet potatoes thrive in loose, sandy soil, so adding compost or aged manure can be beneficial.
Planting:
Over-Wintered Plants: We plant the over-wintered sweet potato plants along with the rooted vine cuttings in the prepared beds.
Mulching: The beds are mulched with double-ground hardwood bark mulch. Mulching helps retain moisture, regulate soil temperature, and suppress weeds.
Watering: We install drip tape on a timer to water the plants every night, ensuring consistent moisture without overwatering.
Harvesting Sweet Potatoes
Timing:
Sweet potatoes are typically ready to harvest in the fall, just before the first heavy frost.
Harvesting Process:
Digging Up Tubers: Carefully dig up the sweet potatoes to avoid damaging the tubers.
Post-Harvest Care: After harvesting sweet potatoes in the fall, we remove the tubers from the roots and prune the vines back to two leaves from the root crown. The sweet potato roots are then potted up into 1-gallon pots with garden soil and stored in our house over the winter.
Post-Harvest Bed Care
Cover Cropping:
After harvesting the sweet potatoes, we seed the beds with a cover crop seed mixture. Cover crops help replenish soil nutrients, improve soil structure, and prevent erosion during the winter months.
Tips for Success
Selecting Varieties: Choose sweet potato varieties that are well-suited for cooler climates and have a shorter growing season.
Frost Protection: Be prepared to protect young plants from unexpected late frosts by using row covers or cloches.
Regular Monitoring: Check the moisture levels in the soil regularly and adjust the watering schedule as needed to ensure the plants do not dry out or become waterlogged.
Pest Management: Keep an eye out for common sweet potato pests, such as wireworms and aphids, and manage them promptly to avoid damage to the plants.
By following these steps, we’ve successfully grown, harvested, and replanted sweet potatoes in our Zone 5 garden year after year. With a bit of planning and care, you too can enjoy the rewards of homegrown sweet potatoes in a cold temperate climate. Happy gardening!
