Sweet Potato Slips

Duration: 15 – 20 minutes the first day, 1 minute each day for 4 – 6 weeks after that until planting, 4 – 5 months until harvesting
Recommended Ages: 5-7 with adult supervision, 8-12 with some adult supervision, 13+ without supervision.
Description:  Prepare your garden for the summer and fall by learning how to propagate sweet potatoes, as well as the importance of sweet potatoes to the 18th century diet.

Colonial Gardening

Enslaved people in colonial Virginia tended gardens of their own, despite working for their owners six days a week. Sunday, the one day many were free from responsibilities for their owners, was their only day to do everything that was important to them like learning to read, worshipping, visiting friends and family, selling their produce at market, or simply relaxing. Without much time and with little land available, enslaved individuals planted only  small areas. A first-hand report by Julian Niemcewicz, who visited Martha and George Washington’s plantation, Mount Vernon, gives us some details. He described a dwelling for enslaved families, including, “A very small garden planted with vegetables was close by, with 5 or 6 hens.” Archaeological digs at sites of slave housing have turned up evidence of garden vegetables that support letters like Julian’s. 

People held in slavery gardened for numerous reasons. The additional food they grew was likely an important part of their diet. Slave owners, like George Mason, provided rations, often in the form of cornmeal and maybe salted fish or less desirable cuts of meat, to the people they kept in bondage. Rations were often inadequate to families’ needs, and they were always monotonous. Enslaved men and women gardened to provide more calories and a greater diversity of flavors for their families. Enslaved communities may also have been motivated to garden because it connected them to their shared cultural heritage. Many of the crops they grew like okra and black-eyed peas originated in Africa and arrived in America as part of the slave trade. Other crops like sweet potatoes were adopted by enslaved gardeners in America. All of these crops could be prepared in traditional, familiar ways. Enslaved gardeners were also motivated by opportunities to sell their surplus crops in local markets or to their masters. Thomas Jefferson and George Washington’s records indicate occasional purchases of produce from the people they enslaved. 

Enslaved individuals existed within a system that did not fully recognize their humanity. Their ongoing struggle to assert themselves as individuals occurred, in part, through gardening. Men and women held in bondage may have seen gardening as a way to better control their food supply, to assert themselves as a community with shared experience and knowledge, and to improve their standard of living.

Detail of ‘Ipomea batatas’ or Sweet Potatoes from The Herball or, Generall Historie of Plantes gathered by John Gerard, 1597. Courtesy of HathiTrust.

Click on the button below to learn more about foods cultivated by enslaved Africans.

Today, you can learn how to grow sweet potato ‘slips.’ Sweet potatoes cannot simply be cut up into small pieces and put into the ground  as regular potatoes can. Green shoots must first grow out of a whole sweet potato. The new foliage can be cut to make a ‘slip.’ These little tiny plants called ‘slips’ are used to make new sweet potatoes that will do great in your garden. A single sweet potato may make several dozen slips; each slip can yield several sweet potatoes in the fall! 

If you’re not ready to grow your own sweet potatoes, but want to  learn more about how colonial gardens gave rise to American cuisine, check out our recipe for:

What do you need?

Both Methods:
Whole organic sweet potato: Organic sweet potatoes begin growing much faster than non-organic ones, we recommend using organic sweet potatoes for this process.
Scissors
Water
A warm spot

See the descriptions below for the specific supplies for each method.

Sweet potatoes like this are on their way to making ‘slips.’ Orient the growing parts upwards. It will never be perfect, but the plant will orient itself over time.

Both Methods

Select a sweet potato(es). We recommend setting up 3 or 4 plantings as a safety net in case some fail to sprout and to make enough “slips” for a home garden. Make sure the sweet potato is not visibly damaged or bruised (see the examples in the picture). 

These healthy sweet potatoes are ready to grow.
Sweet potatoes like these, with scar tissue and black patches, are more likely to rot and decay than produce healthy slips.

Cup Method

Other supplies

A Cup: It must be wide enough to fit a sweet potato
Tooth picks

Water

1. Double check that the sweet potato fits into the cup you plan to use. Take 4 toothpicks and press them into the sweet potato to make a ring around the potato about half way down.

2. Place the sweet potato into your cup; and fill it with water about a half inch below the tooth picks. Water up to the toothpicks will spill and may cause rot. 

3. Find the warmest and sunniest place in your house. Place your cup there. Sweet potatoes thrive in temperatures over 80˙.  A warm space will grow faster and produce many more ‘slips’ than a cool one. A sunny windowsill or a well-lit room near a radiator are good options.

4. Check every few days to ensure that the water level is keeping the lower half submerged. As new roots form, make sure they remain underwater. Visually check for areas that are off-color, as these may be rotting. If this happens, the set must be discarded. If the water becomes cloudy pour it out and refill the cup with fresh water. Within a few weeks sweet potato slips will appear.

5. Cut these slips at the base of the sweet potato when they are 6 or more inches long. Place them in a small cup of water until roots emerge and grow 2 to 3 inches long.

6. Remove the bottom third of the leaves and directly plant the slips into soil. June and July are good times to start planting; the earlier the better. Water them every day during the first week. Keep the soil damp while they are establishing.

7. Sweet potatoes grow all season long. Begin digging around the base of your plants before the first frost. Be careful not to damage the fresh tubers. This may be done in late September or early October.

8. Once you have harvested the sweet potatoes, leave them in a warm space or garage for 1 to 2 weeks to help the roots develop a full skin. This process, called curing, helps them keep longer than just storing them right away. Once you have cured your sweet potatoes, store them in a location that is cool, dry, and dark.

The first root is circled in red. Because it is above the water level, we need to add more liquid.

Pot Method

Other Supplies

Flower Pot: It must be deep enough to fully bury a sweet potato.
Soil

Step 1: Place your sweet potato in your pot.
Step 1: Place your sweet potato in your pot.
Step 1: Cover your sweet potato with 1-2 inches of soil.
Step 1: Cover your sweet potato with 1-2 inches of soil.

1. Make sure your pot is deep enough to cover all the sweet potatoes and to allow 3 to 4 inches between each. Add some soil to the bottom of your pot. Place sweet potatoes in the pot 2 to 3 inches apart. Cover with 1 to 2 inches of soil.

2. Find the warmest and sunniest place in your house. Place the pot there. Sweet potatoes thrive in temperatures over 80˙. A warm space will grow faster and produce many more ‘slips’ than a cool one.. A sunny windowsill or a well lit room near a radiator are good options.

3. Check every 2 to 3 days and water as needed. Soil must remain moist but not soppy. Overwatering will cause rotting. Lightly touching the soil surface is a good way to check. Within a few weeks sweet potato sprouts will appear. 

4. Cut these sprouts off at the soil level when they are six or more inches long. This may take a month or so. Place them in a small cup of water until roots emerge and grow 2 to 3 inches long.

5. Remove the bottom third of the leaves and directly plant the slips into soil. Plant in June and July; the earlier the better.  Water them every day during the first week! As you harvest you may leave your mother plant growing. It will continue to produce slips over the coming weeks.

6. Sweet potatoes grow all season long. Begin digging around the base of your plants before the first frost. Be careful not to damage the fresh tubers. This may be done in late September or early October.

7. Leave in a warm space or garage for 1 to 2 weeks to help the roots develop a full skin. This process, called curing, helps them keep longer than just storing them right away. Once cured, place your sweet potatoes in a location that is cool, dry, and dark.

Native Plants, Imports, and Subsitutions

Many of the crops grown by enslaved peoples were first cultivated in Africa. These crops included okra, black-eyed peas, watermelon, peanut or goober nut, black rice, sorghum, and finger millet. Names and more common uses of these crops recall their African heritage. The English name ‘okra’ evolved from Igbo, a language spoken in Nigeria, word ‘okuru.’ Okra was also called ‘ngombo’ in several different Bantu languages. Today the Bantu word ngombo refers to okra soup or gumbo. Finally, the peanut, which is often called the goober nut, recalls the Bantu word ‘nguba.’ 

Enslaved gardeners in the English colonies adopted crops to replace the African crops that did not grow well in the Americas. Crops domesticated, or first cultivated, in Africa are adapted to more tropical climates. As a result, many crops from West Africa do best with long warm growing seasons. The tropical climate of Africa allowed for the cultivation of different greens that were fundamental to many of the culinary traditions from West Africa. Many of these greens like African spinach, rugare, and cocoyam leaves could not be grown successfully in the colonies. Instead, members of enslaved communities grew greens from Europe like collards and spinach, as well as greens from the Americas like amaranth (also called callaloo) instead. Yams were the most important staple crop in Africa, but they could not be grown in the shorter growing seasons in the English colonies. Sweet potatoes, originally cultivated in the Americas, are similar to yams, and descendants of African peoples brought to the Americas widely adopted them as a substitute.

The adoption and movement of crops in this time period was multi-directional. Europeans conducting trade took many crops from Europe and the Americas to Western Africa during the colonial era. Adam Afzlius, a Swedish botanist, traveled to Sierra Leone in the 1790s and observed the cultivation of a wide variety of European and American crops. He reported that “Cabbage, purslane, sage, certain kinds of beans, . . .thyme, cresses. . .and some American vegetables thrive.” These American crops may have included corn and sweet potatoes. These imported crops joined root crops and grains as important food stuffs for West Africa, enriching the diverse agricultural systems that thrived in the region. 

The exchange of crops within the Atlantic world created diverse outcomes. Many among the lowest social classes in Europe and Africa benefited from the sharing of staple crops types like corn, sweet potatoes, or potatoes. Yet, the growing consumer demand in Europe for cash crops like tobacco, sugar, and rice helped to solidify and expand the institution of slavery.