Despite the summer’s drought, this was a great growing season for sweet potatoes. While they are tropical plants and typically associated with being grown in more southern climates, many varieties do well here in New England. They are not related to potatoes but rather, morning glories.

Sweet potato flowers look like morning glories as they are part of that family. Photo by dmp2022.

Not only are sweet potatoes a highly nutritious vegetable, they are easy to grow with few pests in this area. Native to the Americas, sweet potatoes contain high levels of vitamins A and C along with supplying iron, potassium, and dietary fiber. An average sized sweet potato only has around 120 calories.

To harvest a good crop, sweet potatoes need a growing season of between 90 and 120 days depending on the variety. My favorite choice is ‘Beauregard’, which matures in 90 days so if we have a colder than average spring, there is still enough time for a sizeable harvest. ‘Georgia Jet’ in another variety that matures in 90 days and ‘Centennial’ in 100. ‘Bush Porto Rico’ takes a little longer to mature (110 days) but is a more compact variety for smaller gardens and containers. All of these varieties have dark orange flesh but for those looking for something different, sweet potatoes can be found with white, yellow and even purple flesh.

Rule number one when growing sweet potatoes is to give them enough room to run. Once the warm weather hits, the vigorous vines cover a sizeable area. I planted 12 slips in a 6 by 15-foot bed and they still rambled into neighboring beds and out into the lawn area.

Sweet potato vines escaping from the garden. Photo by dmp2022.

While potatoes are started with pieces of the actual tuber, sweet potatoes are started from slips, which are basically cuttings off a mother plant with a small amount of root and a few leaves. The sweet potatoes that we eat are the plant’s tuberous roots.

Sweet potato slip. Photo by dmp2022.

Being of southern origin, sweet potatoes can take the heat and even some drought and need to be grown in a sunny site with well-draining soil. If your soil is on the sandy side, so much the better as well-aerated soils promote the formation of more roots. I grow them in a slightly raised bed but have seen directions for creating small mounds to grow them in if your soil is rocky or compacted.

Not many garden centers carry edible sweet potato slips or plants so your best bet would be to order them from a seed/plant company online. Order early, like in January, to ensure you get the variety you want. A dozen slips will easily feed a family of four and usually that is the smallest amount one can order. When the slips come in, place them in a container of water for a day or two to hydrate them before planting.

Hopefully the arrival of your sweet potato slips will coincide with good planting weather. Ideally they should be planted 3 or 4 weeks after the last spring frost or when the soils warms up to 65 degrees F. I have held them for a week all together in a pot with some soilless media in a bright but not full sun window.

Plant the slips deep enough to cover the roots, usually 6 inches deep or so. Space plants about 30 inches apart to allow plenty of room for tuberous root formation. Plants could be watered in with a high phosphorus liquid fertilizer. Keep them moist for the first two weeks to ensure good root establishment. After that, water when the soil dries out and no rain is predicted. Avoid planting in soils that have recently had manure added. Do not overfertilize with nitrogen as plants may produce lots of foliage and not a lot of sweet potatoes.

Harvest after the frost starts to blacken the foliage. Cut back the vines and gingerly start digging with a trowel or small shovel about 18 inches from plant crowns. The crowns can be tugged upon and if the soil is loose, where the sweet potatoes are is often obvious and they can be removed from the soil.

Sweet potato foliage blackened by frost. Photo by dmp2022.

While some sources say not to wash them, this year with all the rain made them pretty muddy so I washed them off and set them in the sun to dry.

Fresh dug sweet potatoes covered with mud. Photo by dmp2022.

Try not to bruise them and store in a humid place around 55 degrees F. Curing at 80 degrees and high humidity for 10 days is suggested to improve storage but it is hard to find these conditions during a New England fall. I just let them dry and wipe off any soil that was clinging to them and store in a bin in my cool basement. My sweet potatoes really varied in sizes with some being quite large – probably just need one for a sweet potato pie.

Some huge sweet potatoes! Photo by dmp2022.

I learned my lesson in past years not to leave them in the ground too long after the frost kills back the vines. Voles and slugs also find sweet potatoes delectable and will start nibbling on them if not harvested in a timely fashion.

Portions of my sweet potatoes were feasted on by slugs or voles. Photo by dmp2022.

So if you are looking for something different to grow as you peruse 2023 seed/plant catalogs, why not try sweet potatoes. Except for some feeding damage on the potatoes, I did not have any other insect or disease problems. After they were established, I just mulched and did not add any additional water this year and got quite a good size harvest, despite the summer’s drought.  

Dawn P.