Grow Sweet Potatoes in Soil Bags: A Space-Saving and High-Yielding Method

If you’ve ever dreamed of growing your own sweet potatoes but lack garden space, growing them in soil bags is a game-changer.

Over the years, I’ve experimented with different container gardening techniques, and soil bags have become my go-to for root crops like sweet potatoes. They are space-efficient, allow better drainage, and make harvesting incredibly easy.

Whether you have a small backyard, a balcony, or even just a patio, you can grow a bountiful sweet potato harvest in soil bags. Let me walk you through everything you need to know for a successful crop.

Why Grow Sweet Potatoes in Soil Bags?

Growing sweet potatoes in soil bags offers several advantages over traditional ground planting. First, it’s a fantastic solution for small spaces or urban gardening. You can easily place the bags on patios, balconies, or even along pathways.

Secondly, soil bags provide excellent drainage, preventing waterlogging and reducing the risk of root rot. Plus, they keep weeds and many soil-borne pests at bay. In addition, at harvest time, you can simply dump out the bag and collect your sweet potatoes without excessive digging or damage.

What You’ll Need

Before you start, gather the following materials:

• Sweet potato slips – These are young shoots grown from mature sweet potatoes. You can purchase them from nurseries or sprout your own.
• Heavy-duty soil bags – 15-20 gallon grow bags, burlap sacks, or sturdy plastic bags with drainage holes work best.
• High-quality soil mix – A loose, well-draining mix with compost, sand, and perlite is ideal.
• Fertilizer – A balanced organic fertilizer (such as 10-10-10) to promote root growth.
• Watering can or hose
• Mulch (optional)

Step-by-Step Guide to Growing Sweet Potatoes in Soil Bags

1. Prepare the Soil Bags

Start by choosing durable soil bags that can support the weight of the soil and developing roots. Punch a few drainage holes in the bottom and lower sides to ensure proper water flow. If using plastic bags, roll down the sides to about half their height to provide stability for young plants.

Next, fill the bag with a nutrient-rich, well-draining soil mix. A combination of compost, garden soil, and sand or perlite helps create the loose, aerated environment sweet potatoes love.

You should avoid heavy clay-based soil, as it can hinder tuber development.

2. Choose and Prepare Your Sweet Potato Slips

Sweet potatoes aren’t grown from seeds; they require slips. These are young shoots that sprout from mature sweet potatoes. You can either buy slips or grow your own by placing a sweet potato in water or damp soil until sprouts emerge.

Once they are 6-8 inches long, remove them from the mother tuber and place them in water until they develop roots.

3. Plant the Slips in Soil Bags

Once your slips have roots, plant them in the soil bags. Make holes about 4 inches deep and space them 12 inches apart.

Each bag can comfortably hold 3-4 slips, depending on its size, then cover the roots with soil, ensuring the leaves remain above the surface. Water the slips thoroughly after planting.

4. Provide Proper Sunlight and Watering

Sweet potatoes thrive in full sun, so place your soil bags in a spot that receives at least 6-8 hours of direct sunlight daily.

Water consistently, keeping the soil moist but not soggy. Overwatering can cause rot, while underwatering may lead to smaller tubers. Aim for about an inch of water per week, increasing slightly during hot weather.

5. Fertilize for Optimal Growth

During the first few weeks, apply a balanced organic fertilizer to encourage vine and root development. Once the vines establish themselves, switch to a low-nitrogen fertilizer (such as 5-10-10) to encourage tuber formation instead of excessive leafy growth.

Applying compost or liquid seaweed extract every few weeks can also boost plant health.

6. Train and Maintain the Vines

Sweet potato vines tend to sprawl, so consider training them upward on a trellis or letting them spread naturally.

You can also trim back excessive growth to direct energy toward root development. If growing multiple bags, space them apart to allow proper airflow and prevent overcrowding.

7. Mulching and Pest Prevention

Adding a layer of mulch, such as straw or dried leaves, helps retain moisture and keeps the tubers cool.

Be on the lookout for pests like aphids and whiteflies. Neem oil or insecticidal soap can help keep them under control. If you notice signs of disease, remove affected leaves promptly to prevent the spread.

8. Know When to Harvest

Sweet potatoes typically take 90-120 days to mature. The best indicator that they’re ready is when the vines begin to yellow and die back. To check if they’re ready, carefully dig around the base and feel for mature tubers.

9. Harvest Without Damaging Tubers

One of the best things about growing sweet potatoes in soil bags is how easy they are to harvest.

Instead of digging up the roots with a shovel, simply tip over the bag and sift through the loose soil. Gently brush off excess dirt without washing the tubers, as they need to cure before storage.

10. Curing and Storing Your Sweet Potatoes

After harvesting, cure your sweet potatoes by placing them in a warm (80-85°F), humid environment for 10-14 days. This process improves their flavor and helps them develop a longer shelf life.

After curing, store them in a cool, dark place with good air circulation. Properly cured sweet potatoes can last for several months.

Common Mistakes to Avoid

• Overwatering: Sweet potatoes hate soggy soil. Ensure good drainage in your soil bags to prevent root rot.
• Planting too early: Wait until temperatures are consistently warm (above 65°F) before planting slips.
• Using poor soil: Compact or heavy soil will stunt growth. Stick to light, aerated potting mixes with added compost.
• Not spacing properly: Crowded slips can limit tuber growth. Give each slip at least 12 inches of space.
• Harvesting too soon: Patience is key! Wait until vines naturally die back before pulling up your sweet potatoes.