An ideal staple crop for those seeking to meet most of their food needs with homegrown produce would be nutrient-dense, offer high yields, and have excellent flavor and storage qualities. A crop that fits this bill perfectly? The sweet potato.
Sweet potatoes are more nutritious and store better than any other root crop — they’re easy for home gardeners to keep for a full year. And while many people think of them as a Southern crop, you can in fact easily grow sweet potatoes in northern climates.
Sweet potatoes are nutritious, starchy root vegetables. Sweet potato plants are in the same family as morning glories (Convolvulaceae), and are only distantly related to potatoes. Since they are not in the nightshade family (Solanaceae) with potatoes, sweet potatoes are a dietary alternative for people who are sensitive to nightshades.
Sweet potato plants are heat-loving, low-maintenance garden vegetables. They have a vining growth habit and the plants establish quickly. They enjoy full sun (at least 6-8 hours during the growing season) and thrive in loose, well-drained, nutrient-rich soils – although they will tolerate almost any planting site.
Planting Sweet Potatoes
The best time to plant sweet potato plants is after the ground is thawed and after the last spring frost date has passed. If the ground doesn’t freeze in your location, then the best time to plant is usually a month after your last spring frost date.
Prepare the soil. Sweet potatoes grow well in nutrient-rich soil, so prepare the sunny, well-drained planting site with compost or well-aged manure prior to planting. If your soil has water-retention issues, you may need to amend with coir, or coco-fiber growing medium. If your soil is compact or composed of heavy clay, it is recommended that you build raised beds or large mounds of top soil (amended if needed) to plant and grow sweet potatoes. Building up 10-12 inches above the native soil should work fine.
If you can’t plant your sweet potatoes when they arrive, due to adverse weather conditions, keep sweet potato plants’ roots damp and put them in a shaded place until conditions improve.
Plant. Space planting holes at least 12 inches apart and space planting rows about 36 inches apart. This allows space for vigorous vines to grow and avoids light or nutrient competition, while also giving you room to move easily through your planting site to mulch, water, and eventually harvest.
Mulch. Sweet potato plants don’t like water-logged soil, but dry soil is just as stressful. Be sure to keep the planting area watered as needed (you shouldn’t need to water if there is rain in the near forecast). Apply a few inches of mulch to help retain moisture while also discouraging the development of problematic weeds.
Maintenance of the planting site
- Remove weeds as soon as they appear to keep the task manageable.
- Apply additional fertilizer or soil conditioners as needed about a month after planting.
- Avoid overwatering, but irrigate as needed to keep planting site from drying out.
- Pruning is not needed and often not recommended.
Most varieties of sweet potato will mature within 3-5 months, so, if your location is known for having short growing seasons, be sure to choose varieties with an appropriate maturity time.
Carefully remove the soil from around the plant’s roots and examine the tuber size. If they are a couple inches across or larger, they are ready to be harvested. You can selectively remove the sizable sweet potatoes and re-cover the plant’s roots to allow continued development of smaller ones. Be careful not to bruise, scrape, or puncture the skin of the sweet potatoes as this can cause quality issues like rotting, especially in storage. Remove any excess dirt from your harvest.
To fully enjoy your harvested sweet potatoes, they will likely need a curing period to develop the sugars for the sweetness you are familiar with. This curing process is also necessary if you plan to store your sweet potato harvest for several months.