Sweet Potatoes for the Home Garden: Your First Crop From Slip to Storage

Sweet potatoes are one of the most rewarding crops a home gardener can grow, and they deserve a place in every Southeast garden. A handful of slips planted in June can produce enough tubers to feed a family through the winter if stored properly.

Unlike regular potatoes that grow from seed pieces cut from a tuber, sweet potatoes come from slips. Slips are sprouts that grow from a stored sweet potato tuber, and they look like long green stems with a few leaves at the top. You can buy slips from garden centers or mail-order catalogs in spring, or grow your own from a stored sweet potato placed in a jar of water.

This guide covers everything from choosing your first batch of slips to storing the harvest through winter, all tailored for Zone 7a gardens.

Why Sweet Potatoes Are Worth Growing

Sweet potatoes are unusually forgiving for a crop that takes up a fair amount of garden space. They grow in poorer soils where regular potatoes might struggle. They are naturally pest-resistant in most home garden settings. And once you get the hang of the basic care, they require almost no attention from planting through harvest.

The other benefit is storage. A properly cured and stored crop of sweet potatoes will keep for six to twelve months at room temperature in a cool place like a basement or garage. That means you can plant in June and eat from your garden all the way through next spring.

Choosing Varieties for the Southeast

Sweet potato varieties fall into two groups: those bred for the humid Southeast and those bred for the drier West. For Tennessee and the surrounding states, you want Southeast varieties.

Beauregard is the most popular variety in the Southeast. It matures in about 100 days, produces well, and has rich orange flesh that people recognize as a sweet potato. It adapts well to a wide range of soil conditions.

Jewel matures in about 110 days and produces firm tubers with deep orange flesh. Many people prefer its flavor to Beauregard. It stores well through winter.

Georgia Jet matures in about 100 days and is a good option if you have a shorter season or live in the northern part of Zone 7a. It is more disease-resistant than some other varieties, though it does not store quite as long.

Centennial matures in about 120 days and produces very large, uniform tubers. It is best for gardeners who want big storage-size potatoes and have a full-length season. It is less suited to shorter seasons or northern Zone 7a.

For your first crop, go with Beauregard or Georgia Jet. Both mature quickly, are easy to find at garden centers, and handle Zone 7a conditions well.

Getting Your Slips

You have two options for getting started: buying slips or growing them yourself.

Buying slips is the simplest approach. Most garden centers in the Southeast stock slips from late April through June. Mail-order catalogs like Burpee, Johnny's Selected Seeds, and Southern Exposure Seed Exchange also ship slips in spring. If you order from a catalog, place your order by early spring so they arrive in time for planting.

Growing your own slips costs nothing and gives you a larger selection than most garden centers carry. Place a sweet potato in a jar of water with the bottom third submerged. Set it in a warm, sunny spot. Within a few weeks, long slips will emerge from the eyes. When the slips are about six to eight inches tall, twist or cut them off and place them in a glass of water on a windowsill. Roots will develop in a few days, and they are ready to plant once the soil is warm enough.

A single sweet potato can produce dozens of slips. Many gardeners grow their own slips and share extras with neighbors.

When and How to Plant

Sweet potatoes need warm soil. They will not grow in cold ground. Plant your slips when the soil temperature has reached at least 65 degrees Fahrenheit, and 70 degrees is better. In Zone 7a, that means planting between late May and mid-June.

This is usually the last crop you plant in the spring. Tomatoes, peppers, okra, and summer squash all go in before sweet potatoes. If you are still thinking about planting sweet potatoes in July, it is not too late, but your variety choice matters more. Stick to shorter-season varieties like Georgia Jet or Beauregard.

To plant a slip, dig a shallow trench about four to six inches deep. Lay the slip horizontally in the trench, leaving about two to three inches of the tip above the soil. Cover most of the slip with soil and firm it down. The buried portion will develop roots and new shoots.

Space slips 12 to 18 inches apart in rows that are three to four feet apart. Each slip will grow into a plant that sends out multiple vines.

Some gardeners mound soil up around the base of the planted slip to help warm the soil and encourage rooting. This is optional but can be helpful if the ground is still cool.

Growing and Care

Once sweet potatoes are established, they are low-maintenance. The main things to watch are water and weeds.

Watering is important during the first few weeks while the slips are rooting and establishing. After that, sweet potatoes are fairly drought-tolerant. During dry periods in July and August, water deeply once a week if rainfall is light. Overwatering in the last month before harvest can cause tubers to crack, so taper off watering as you approach harvest time.

Fertilizing should be minimal. Sweet potatoes grow vines easily, and too much nitrogen produces a large leafy canopy with few tubers. If your soil is in decent shape, you do not need to fertilize at all. Some gardeners work a small amount of compost into the bed at planting time. Avoid high-nitrogen fertilizers.

Weeding is easiest when the plants are small. Sweet potatoes are excellent ground cover once they establish, and their vines will shade out most weeds within a few weeks. A light hoeing in the first month is usually all the weeding you need.

Common Problems

Sweet potatoes are remarkably pest-resistant compared to most garden crops. In a home garden setting, you should run into very few problems.

Vine borers are the most common pest. They chew tunnels into the vines, causing wilting. Remove affected vines and destroy them. The damage rarely kills the plant if caught early.

Weevils can be a problem in some areas. Sweet potato weevils are most common in the southern part of the range. In eastern Tennessee they are less common, but if you notice holes in tubers or wilting vines, check for the beetles. Crop rotation and clean harvest help prevent weevil buildup.

Poor tuber set usually results from planting too early. If you plant slips when the soil is still cold, the plant spends its energy producing vines instead of tubers. This is the most common mistake new sweet potato growers make.

Planting tubers instead of slips is another common error. Do not bury a whole sweet potato in the ground and expect a crop. You need slips. Start your own from a grocery store sweet potato, or buy them from a garden center.

Harvest and Curing

It is tempting to pull up a sweet potato after a few weeks to see what is happening, but resist the urge. Sweet potatoes need the full growing season to reach their potential size and develop proper skin that stores well.

Harvest time in Zone 7a is usually late September to mid-October. The signal to watch for is the vines turning yellow and starting to die back. This indicates the tubers are mature.

Plan to harvest before the first hard frost. A light frost will not damage mature tubers, but a hard freeze will. If frost is expected and the vines are still green, harvest immediately.

Here is how to harvest: use a garden fork and start digging about eight inches away from the main plant stem to avoid piercing tubers. Gently lift the soil and work your way out from the center. The tubers should be fairly easy to find once you are in the right area.

Curing is essential. After harvesting, you must cure the tubers to heal the skin and make them store well. Cure at 80 to 85 degrees Fahrenheit with high humidity for 7 to 10 days. A greenhouse, sunroom, or enclosed porch works well in a pinch. If you cannot maintain that temperature, store them as a short-term test and eat those tubers first.

Do not wash sweet potatoes after harvesting. Brush off loose soil and cure them as-is. Washing removes the protective outer layer and shortens storage life.

Storing Through Winter

Properly cured sweet potatoes store best at 55 to 60 degrees Fahrenheit with 60 to 75 percent humidity. A basement, root cellar, or unheated garage in Zone 7a is usually the right temperature range.

Do not store sweet potatoes in the refrigerator. Temperatures below 50 degrees cause chilling injury, and the tubers will develop hard centers and a bitter taste that does not cook out.

Check stored tubers every few weeks and remove any that show soft spots or signs of rot. One bad potato can spoil the whole batch.

Stored properly, sweet potatoes will keep for six to twelve months. The older they get, the sweeter they become as the starches convert to sugar during storage.

Getting Started

A home garden with a 10-foot row of sweet potatoes, planted in June and properly stored, can provide a steady supply of fresh tubers from September through the following summer. That is a lot of food from a small patch of ground.

Start with a single variety like Beauregard. Get your slips from a garden center or grow your own from a grocery store sweet potato. Plant in late May when the ground is warm. The rest mostly takes care of itself.

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— C. Steward 🍠