When you think of “fresh from the garden,” the sweet potato might not be the first vegetable that comes to mind. This tropical-by-nature crop, with its long, sprawling vines and mysterious underground treasure, can seem intimidating to a home gardener. Unlike a regular potato, you can’t just cut it up and plant the pieces. In fact, for many gardeners, growing sweet potatoes feels like an advanced skill, reserved for those in the deep south with endless, hot summers.

Here’s the good news: that’s simply not true. Growing sweet potatoes is surprisingly easy, provided you understand three key things: they are not potatoes, they love heat, and the harvest isn’t over when you pull them from the ground. With a little bit of knowledge and the right head start, almost anyone with a sunny garden can grow a “slip” into a 20-pound harvest. This guide will walk you through the entire unique process, from planting the “slip” to the all-important final cure.

Sweet Potatoes vs. Yams: Clearing Up the Confusion

First, let’s clear up a common point of confusion, especially in US supermarkets.

• Sweet Potatoes (Ipomoea batatas): These are what you are growing. They are in the morning glory family, native to Central and South America. They have smooth, thin skin (which can be copper, tan, or purple) and tapered ends. The flesh can be orange, white, or purple.
• True Yams (Dioscorea species): These are an entirely different plant, native to Africa and Asia. They are large, starchy, cylindrical tubers with a rough, scaly, and thick skin, more akin to bark.

So, why the confusion? In the United States, grocery stores often label the soft, orange-fleshed sweet potato varieties (like Covington or Beauregard) as “yams” to distinguish them from the firm, pale-fleshed sweet potato varieties. For this guide, just know we are talking about Ipomoea batatas, the true sweet potato, regardless of what your market calls it. For more detail, Mississippi State University Extension Service offer in-depth comparisons.

Understanding Sweet Potato “Slips”

This is the most fundamental concept you must grasp. You do not plant sweet potato “seeds” (which are unreliable and for breeders) or “seed potatoes” (like you do with regular potatoes). You plant slips.

A slip is a small, rooted sprout that is grown from a mature, cured sweet potato. These slips are the “starts” that you will plant in your garden. This is a critical distinction because it changes how and when you acquire your plants. You can either buy these slips from a nursery or grow your own.

How to Grow Your Own Slips (The Classic Experiment)

This is a fantastic and fun project, especially if you have kids. It’s the classic “sweet potato in a jar” experiment, but it’s a perfectly viable way to get your plants.

1. Start 6-8 Weeks Before Planting: You need to start this process well before your soil is warm.
2. Use an Organic Sweet Potato: Many store-bought sweet potatoes are treated with a chemical to prevent them from sprouting. Use an organic sweet potato, or one from a farmer’s market.
3. Suspend in Water: Find a clean jar. Stick three or four toothpicks into the middle of the sweet potato and use them to suspend it over the jar’s rim, so the bottom half of the potato is submerged in water and the top half is in the air.
4. Place and Wait: Put the jar in a warm, sunny spot. Change the water every few days to keep it fresh.
5. Watch the Magic: After a few weeks, you will see roots growing in the water and—most importantly—leafy green sprouts (the slips) growing from the top.
6. Harvest the Slips: When a slip is about 5-6 inches long, gently twist it off the mother potato. Place the harvested slips in another jar of water (so only the bottom inch of the stem is wet). They will develop their own roots in about a week.

Once a slip has its own set of roots and all danger of frost has passed, it is ready to be planted in the garden.

Where to Buy Quality Slips

Growing your own slips is fun, but it’s not the most reliable method. The easiest and most common way to start is to buy your slips.

• Local Nurseries: As planting time approaches, most garden centers will sell bundles of bare-root sweet potato slips, usually tied together with a rubber band.
• Mail-Order: For a much wider variety (from Japanese purple potatoes to white-fleshed boniatas), ordering from a reputable online nursery or seed catalog is a fantastic option. They will ship the live slips to you at the correct planting time for your zone.

Planning Your Sweet Potato Patch

Growing sweet potatoes requires two things in abundance: sun and heat. They are a tropical plant and will not compromise on this.

The Heat-Loving Nature of Sweet Potatoes

This is a warm-season crop in the extreme. Do not, under any circumstances, try to plant these in cool spring soil.

• Long Growing Season: They need a long, hot season to develop large tubers—typically 90 to 120 days of consistently warm weather.
• Sunlight: Choose the absolute sunniest spot in your yard. A minimum of 8 hours of direct, unfiltered sun is required. A Garden Sun Map: How to Maximize Sunlight for Your Vegetables is crucial for this.
• Warm Soil: The soil temperature should be at least 65°F (18°C) before you even think about planting, but 70°F (21°C) or warmer is even better. They are not frost-tolerant. A single, light frost will kill the vines.

The Best Soil for Sweet Potatoes: Loose and Well-Drained

This is the second critical factor. Sweet potatoes are tubers that grow and expand underground. If your soil is heavy, compacted clay, the roots won’t be able to expand, and you’ll end up with a harvest of long, skinny, stringy roots.

They must have loose, friable (crumbly), well-drained soil. This is why a soil test can be so valuable; you can learn more about How to Read a Soil Test Report: Unlocking Your Garden’s True Potential before you amend.

Containers and Raised Beds: An Excellent Option

Because of their need for loose soil, sweet potatoes are fantastic candidates for The Benefits of Raised Bed Gardening: Maximizing Space and Yield. A raised bed, filled with a mix of compost and loose garden soil, is an ideal environment for them.

They also grow surprisingly well in containers!

• Grow Bags: A 15 or 20-gallon fabric grow bag is perfect.
• Large Pots: A half-whiskey-barrel or a container of similar size can easily support one or two slips.
• Container Benefits: Using a container allows you to give them the Best Soil for Container Vegetables: Crafting the Perfect Potting Mix for a Bountiful Harvest and has the added benefit of making harvest incredibly easy—you just dump the pot out!

How to Plant Your Sweet Potato Slips

Once your soil is warm (late spring or early summer, well after your last frost), it’s time to plant. Your slips should be about 6-12 inches long.

1. Dig a Trench (or Mounds): Many gardeners prefer to plant sweet potatoes in “mounded rows.” This involves creating a long, raised mound of soil that is about 8-10 inches high. This further ensures the soil is loose and drains well.
2. Bury the Slip (Deep): This part feels strange, but it’s correct. Take a slip and remove all but the top 2-3 leaves. Lay the slip horizontally in a shallow trench and bury the stem, leaving only the top leaves exposed to the sun. You can also plant it vertically, burying it about halfway up the stem.
3. Why Bury the Stem? Sweet potatoes will form on every single “node” (the point where a leaf met the stem) that is underground. Planting horizontally like this will give you a much bigger harvest of tubers all along that buried stem.
4. Space Generously: Space your slips 12 to 18 inches apart. The vines will sprawl, but the tubers need this underground space.
5. Water Well: Water your newly planted slips deeply. They will look terribly wilted and sad for the first few days. This is normal. Don’t panic! Give them a week, and they will perk up and establish themselves.

Caring for Your Sweet Potato Vines

Once established, sweet potatoes are remarkably low-maintenance.

Watering: Deep and Consistent

They are fairly drought-tolerant, but a consistent watering schedule will produce a much larger harvest. Like most vegetables, they prefer deep, infrequent watering over a shallow, daily sprinkle. Water deeply once or twice a week, allowing the soil to dry slightly between sessions. Be cautious of Signs of Overwatering: Are You Loving Your Plants to Death?, as soggy soil can lead to rot.

Fertilizing: Go Easy on the Nitrogen

This is a common mistake. Sweet potatoes do not need rich, heavily fertilized soil.

• Compost is Enough: Amending your bed with 2-3 inches of compost before planting is often all they need for the entire season.
• Low-Nitrogen: If you do fertilize, use a balanced Organic Fertilizer for Vegetables or one that is higher in potassium (K) and lower in nitrogen (N).
• The “All-Vine” Problem: Too much nitrogen will cause the plant to put all its energy into growing spectacular, 20-foot-long vines… and zero potatoes underground.

Managing the Sprawling Vines

Sweet potato vines are vigorous and will quickly cover all available space. They can trail 10-15 feet or more.

• Let Them Run: In a large garden, just let them go. They will form a dense, green carpet that acts as a living mulch, suppressing weeds.
• Re-Direct Them: You can gently lift and tuck the vines back into their designated area.
• A Note on Rooting: The vines will try to root themselves at the leaf nodes. Some gardeners lift the vines every few weeks to prevent this, believing it forces energy back to the main tubers. Others find this makes no difference.
• Edible Leaves! Don’t forget, sweet potato leaves are 100% edible and nutritious! They can be sautéed or steamed just like spinach or kale.

Common Pests and Problems

Sweet potatoes are generally pest-resistant. The biggest threat in most gardens is not an insect, but a mammal.

• Deer & Rabbits: They love sweet potato vines. A fence is your only reliable defense.
• Wireworms & Scurf: These soil-dwelling pests can scar the outside of the tubers. The best defense is The Essential Guide to Crop Rotation—don’t plant sweet potatoes in the same spot year after year.

For other minor issues, general Eco-Friendly Pest Control methods usually suffice.

The Big Dig: How and When to Harvest

This is the most exciting and delicate part of the process.

How to Know When They’re Ready

1. Check the Calendar: Note your planting date. Most varieties are ready in 90 to 120 days.
2. Watch the Vines: The vines will often start to yellow and die back as the weather cools.
3. The First Frost: The real deadline is the first frost. The vines will be killed by the first light frost, and this is your non-negotiable sign to harvest immediately. Do not let the tubers sit in the cold, wet ground after the vines have died, or they will quickly rot.
4. “Check” a Tuber (Gently): If you’re impatient, you can gently dig around the side of one plant (a “test hill”) and feel for tubers. If they feel like a good size, the crop is ready.

The Careful Digging Process

Go into this process with patience. The skins of freshly dug sweet potatoes are paper-thin and incredibly easy to bruise, nick, and tear. Every injury is a potential entry point for rot.

1. Tools: Use a spading fork or a “digging fork,” not a sharp shovel. A shovel is more likely to slice right through your prize tubers.
2. Start Far Away: Begin digging about 12-18 inches away from the center of the plant. This helps you avoid stabbing the tubers you can’t see.
3. Loosen the Soil: Use the fork to gently loosen the soil all around the plant.
4. Go by Hand: Once the soil is loose, get on your hands and knees. Gently pull the main crown of the plant up while using your hands to feel for the tubers and pull them out. This is a treasure hunt.
5. Be Gentle: Do not throw the tubers into a bucket. Place them gently on the soil. Do not wash them. Let them air-dry for an hour or two, then gently brush off the large clumps of dirt.

The Single Most Important Step: Curing Your Sweet Potatoes

You’ve got a wheelbarrow full of beautiful sweet potatoes. Your job is not done. This is the step that separates a good gardener from a great one and turns a starchy tuber into a sweet, delicious treat.

Why Curing is Non-Negotiable

Freshly dug sweet potatoes are starchy, not very sweet, and will not store for long. Curing is a process of “intentional healing” that does two things:

1. Converts Starch to Sugar: This is when the magic happens. The curing process activates enzymes that turn the starches into sugars (maltose), developing that sweet, complex flavor.
2. Heals the Skin: Curing allows the thin skin to heal any nicks or scratches, toughen up, and create a protective barrier against rot.

A cured sweet potato will store for 6-10 months. An uncured one will rot in a few weeks.

The Curing Process: High Heat & High Humidity

This is the hard part for home gardeners, but you can create a “DIY” curing chamber. The ideal conditions are 85-90°F (29-32°C) with 85-90% humidity for 7 to 10 days.

How to “Fake” This at Home:

1. Find a Small Room: A small bathroom, laundry room, or walk-in closet works well.
2. Add Heat: Place a small, safe electric space heater in the room and set it to maintain the target temperature.
3. Add Humidity: Place a humidifier in the room. If you don’t have one, you can place pans of water near the heater.
4. Arrange the Tubers: Lay the sweet potatoes out in a single layer on shelves or in crates. Do not let them touch. Ensure there is good airflow.
5. Run the “Chamber”: Let them sit in this hot, humid environment for 7-10 days.

Storing After Curing

After they are cured, move them to a cool, dark, and dry spot for long-term storage. The ideal storage temperature is 55-60°F (13-15°C). Do not store them in the refrigerator; this will cause a “chilling injury” and ruin the flavor and texture.

A Rewarding, Unique Garden Venture

Growing sweet potatoes is a delightful journey that’s unlike growing any other vegetable. It’s a plant that teaches patience, asking you to wait 8 weeks for a slip, 120 days for a tuber, and another 10 days for the all-important cure. But the reward is immense: a single plant can yield pounds of food, and the flavor of a homegrown, properly cured sweet potato is something a grocery store can rarely match.

Check out the author’s book here: The Year-Round Vegetable Garden for Beginners.