How to Grow Sweet Potatoes in Containers: Pot Size, Soil Mix, and Vine Training

Growing sweet potatoes in containers is one of the most reliable ways to get smooth, well-shaped roots—especially if you garden in a small space, have heavy soil, or want to warm the soil quickly in spring. I’ve grown sweet potatoes in large containers for years alongside my raised beds in Sonoma, and the results are consistently impressive: early warm soil, easy harvests, and less pest pressure.

Here’s how to set yourself up for container-growing success.

Table of Contents

Choose the Right Pot Size

Sweet potatoes need space below the soil to stretch out. A container that’s too small produces thin, stringy roots.

Recommended pot size:

Minimum: 15–20 gallons
Ideal: 20–25 gallons
Depth: At least 16–18 inches
Material: Fabric pots, large plastic tubs, or half-barrels work best

My experience:
Fabric pots warm quickly and drain beautifully. My best container harvests have always come from 20-gallon fabric grow bags.

Use a Loose, Warm, Well-Draining Soil Mix

Container success depends almost entirely on the soil mix. Sweet potatoes love warmth and need a soil they can easily expand through.

My proven container mix:

40% high-quality potting soil
40% homemade compost or aged compost
20% coarse sand or perlite

This blend warms quickly, drains well, and prevents compacted, misshapen roots.

From experience:
Pure potting mix is too fluffy; pure compost holds too much water. The 40/40/20 mix has given me straight, sweet, and sizeable tubers every year.

Plant Healthy, Well-Rooted Slips

Container-grown slips establish quickly because the soil warms earlier than in-ground beds.

How to plant:

Fill the pot to within 2 inches of the rim.
Plant one to two slips per 20-gallon container (never more).
Bury slips deep—2–3 inches of stem under the surface.
Water well to settle the soil.

My note:
Overplanting is the fastest way to reduce harvest size. One slip in a 20-gallon pot can easily produce 8–12 good roots.

Keep Containers Warm and in Full Sun

Sweet potatoes thrive in heat. Containers help by warming earlier, but they also dry out faster.

Ideal conditions:

8+ hours of sun
Soil temperatures above 70°F
Growing temperatures above 80°F for best productivity

In Sonoma:
I place my containers along a south-facing fence that radiates warmth well into the evening.

Water Deeply—But Don’t Overdo It

Container sweet potatoes need consistent moisture, especially early on.

Watering schedule:

First month: Moist but never soggy
Mid-season: Water when the top 2 inches of soil are dry
Final 3–4 weeks: Reduce watering to improve sweetness and prevent cracking

Experience tip:
Fabric pots dry out faster in summer heat. I often water every other day during July and August.

Train the Vines for Better Airflow and Easy Care

Sweet potato vines in containers can spill everywhere if not guided.

Easy training tricks:

Wrap vines around the pot edge to keep them tidy
Use a low trellis or tomato cage for light vertical growth
Allow some vines to drape over the sides for maximum photosynthesis
Pinch tips lightly if vines grow too vigorously

Why training matters:
Better airflow = fewer fungal issues
Organized vines = easier watering, feeding, and checking for pests

In my garden, wrapping vines around the lip of the container keeps everything neat and boosts production.

Feed Lightly During the Season

Sweet potatoes don’t need heavy feeding—too much nitrogen produces leaves, not roots.

For containers:

Mix compost into the soil at planting
Apply a low-nitrogen, higher-potassium fertilizer once about mid-season

I often skip fertilizer altogether if the compost is rich.

Harvest Easily—One of the Biggest Benefits

Harvesting from containers is incredibly simple. Just dump the pot into a wheelbarrow and sift through the loose soil.

My experience:
Container-grown sweet potatoes are usually cleaner, smoother, and less damaged than in-ground crops.

Final Thought

Growing sweet potatoes in containers is one of the most flexible and rewarding ways to raise this heat-loving crop. With the right pot size, a warm loose soil mix, and simple vine training, you can grow beautiful, sweet, full-sized roots even in small spaces. My container harvests are among my earliest and most reliable each year—and this method works wonderfully for beginners and experienced gardeners alike.