How To Grow Purple Sweet Potatoes In Containers – Your Guide To

ByRimon Chowdhury Updated on

Ever dreamt of harvesting your own vibrant, nutritious purple sweet potatoes, even if you don’t have a sprawling garden? You’re in luck! Many aspiring gardeners face the challenge of limited space, but that doesn’t mean you have to miss out on the joy of growing your own food. If you’ve been wondering how to grow purple sweet potatoes in containers, you’ve come to the right place.

As an experienced gardener, I’m here to promise you that cultivating these beautiful tubers in pots is not only possible but incredibly rewarding. This comprehensive guide will walk you through every step, transforming your patio, balcony, or small yard into a productive sweet potato patch. Get ready to discover the secrets, tips, and best practices for a bountiful purple harvest right outside your door!

Why Grow Purple Sweet Potatoes in Containers? The Benefits for Every Gardener

Before we dive into the nitty-gritty of how to grow purple sweet potatoes in containers, let’s talk about why this method is so fantastic. There are numerous benefits of how to grow purple sweet potatoes in containers that make it a smart choice for gardeners of all levels.

  • Space Efficiency: This is arguably the biggest advantage. Containers allow you to grow a significant harvest in a small footprint, perfect for urban gardeners, balconies, or patios.
  • Pest and Disease Management: Growing in containers can help isolate your plants from soil-borne pests and diseases, making it easier to monitor and control issues.
  • Mobility: You can move your containers to optimize sunlight exposure throughout the day or protect plants from sudden cold snaps or harsh weather.
  • Soil Control: You have complete control over the potting mix, ensuring your sweet potatoes get the ideal well-draining, nutrient-rich environment they crave.
  • Easier Harvesting: No more digging up large garden beds! Simply tip out the container for an effortless harvest.
  • Unique Nutrition & Beauty: Purple sweet potatoes aren’t just stunning with their vibrant foliage and gorgeous roots; they’re packed with antioxidants, vitamins, and minerals. They’re a superfood you can grow yourself!

Ready to get started? Let’s gather our tools and prepare for a rewarding growing season.

Getting Started: Essential Supplies for Growing Purple Sweet Potatoes

Success in container gardening begins with choosing the right supplies. Don’t worry—you likely have many of these items already, or they’re easy to find!

Choosing the Right Container for Purple Sweet Potatoes

The container size is crucial for sweet potatoes, as they need ample space to form their tubers. Think big!

  • Size: Opt for containers that are at least 15-20 gallons (60-75 liters) in capacity. Larger is always better. A good rule of thumb is 15-18 inches (38-45 cm) in diameter and depth. You can plant 1-2 slips per such container.
  • Material: Fabric grow bags are excellent as they provide superior aeration, prevent root circling, and offer good drainage. Large plastic pots, half-whiskey barrels, or even repurposed sturdy bins (with drainage holes added) also work well. Terracotta can be heavy and dry out quickly.
  • Drainage: Regardless of material, excellent drainage is non-negotiable. Ensure your chosen container has plenty of drainage holes at the bottom to prevent waterlogging, which can lead to root rot.

Selecting Your Sweet Potato Slips

Sweet potatoes are grown from “slips,” which are sprouts taken from a mature sweet potato. You can purchase slips from garden centers or online nurseries, or you can easily grow your own.

  • Where to Buy: Look for reputable suppliers offering disease-free slips. Specify “purple sweet potato” varieties like ‘Okinawan,’ ‘Stokes Purple,’ or ‘Muraski.’
  • Healthy Slips: When buying, choose slips that are vibrant green, sturdy, and free from any signs of pests or disease. They should be 6-12 inches (15-30 cm) long.

The Perfect Potting Mix for Container Sweet Potatoes

This is where many of the how to grow purple sweet potatoes in containers best practices come into play. A good potting mix provides the ideal environment for root development.

  • Well-Draining: Sweet potatoes hate soggy feet. Your mix must drain freely.
  • Rich in Organic Matter: A high-quality organic potting mix designed for vegetables is ideal. Avoid heavy garden soil, which compacts easily in containers.
  • Recipe for Success: A great blend is 60% good quality potting mix, 20% compost or well-rotted manure, and 20% perlite or coarse sand for extra drainage and aeration. This ensures a loose, friable environment that tubers can easily expand into.

Propagating Slips: Your First Step to a Bountiful Harvest

Growing your own slips is a fun, inexpensive, and rewarding way to start your purple sweet potato adventure. It’s a fantastic demonstration of sustainable gardening!

From Store-Bought Sweet Potato: The Water Method

This is a classic and visually appealing method:

  1. Choose a Healthy Potato: Select an organic, unblemished purple sweet potato from the grocery store.
  2. Prepare for Sprouting: Insert 3-4 toothpicks around the middle of the potato.
  3. Submerge: Suspend the potato in a glass of water, with about half of it submerged. Place the glass in a warm, bright location (like a sunny windowsill).
  4. Wait for Sprouts: In a few weeks, sprouts (slips) will emerge from the top, and roots will grow from the bottom. Change the water every few days to prevent mold.
  5. Harvest Slips: Once the slips are 6-8 inches (15-20 cm) long, gently twist or cut them off the potato. Place these slips in a fresh glass of water to root for about a week before planting.

From Store-Bought Sweet Potato: The Soil Method

This method often yields stronger slips:

  1. Bury the Potato: Partially bury a whole or halved purple sweet potato horizontally in a shallow tray or pot filled with moist potting mix.
  2. Keep Warm and Moist: Place it in a warm spot (75-85°F / 24-29°C is ideal) and keep the soil consistently moist.
  3. Harvest Slips: Once slips are 6-8 inches (15-20 cm) tall, carefully pull or cut them from the potato, ensuring they have a few small roots attached. If they don’t have roots, root them in water for a week or two.
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Caring for Your Young Slips

Whether store-bought or homegrown, your slips need a little TLC before planting.

  • Light: Provide bright, indirect light.
  • Warmth: Keep them in a warm environment.
  • Humidity: A humid environment helps them thrive. You can mist them regularly.

Planting Your Purple Sweet Potato Slips in Containers

Now for the exciting part! This section is your practical how to grow purple sweet potatoes in containers guide to getting your plants established.

Timing is Everything

Sweet potatoes are tropical plants and love warmth. Don’t rush this step!

  • Wait for Warmth: Plant your slips outdoors only after all danger of frost has passed and night temperatures consistently stay above 55°F (13°C).
  • Soil Temperature: The soil in your containers should ideally be above 60°F (15°C). Use a soil thermometer if you have one.
  • Growing Season: Aim for a long, warm growing season, usually late spring to early summer, depending on your climate.

The Planting Process

Follow these simple steps for successful planting:

  1. Fill Your Container: Fill your chosen container with your prepared potting mix, leaving about 2-3 inches (5-7 cm) from the rim.
  2. Prepare Slips: Gently remove any lower leaves from your slips, leaving only the top 2-3 leaves. This encourages root development from the nodes.
  3. Planting Depth: Dig a small hole and plant each slip deep enough so that at least half to two-thirds of the stem is buried. This allows multiple nodes to root and produce tubers.
  4. Spacing: For a 15-20 gallon container, plant 1-2 slips. If you have a larger container, you might fit 2-3, ensuring they have ample space to spread.
  5. Water Thoroughly: After planting, water your slips deeply until water drains from the bottom of the container. This settles the soil around the roots.

Initial Care After Planting

The first few days are crucial for your young plants.

  • Shade: For the first 2-3 days, provide some partial shade to help the slips recover from transplant shock, especially if it’s very sunny.
  • Consistent Moisture: Keep the soil consistently moist, but not waterlogged, during this establishment phase.

Nurturing Your Container-Grown Purple Sweet Potatoes: A Care Guide

Once planted, your purple sweet potatoes will need ongoing care to thrive and produce a generous harvest. This is your essential how to grow purple sweet potatoes in containers care guide.

Watering Wisdom

Sweet potatoes are relatively drought-tolerant once established, but in containers, they dry out faster.

  • Consistency is Key: Aim for consistent moisture. Don’t let the soil completely dry out, but also avoid overwatering.
  • Check Daily: In warm weather, you may need to check the soil moisture daily by sticking your finger about an inch into the soil. If it feels dry, it’s time to water.
  • Deep Watering: Water deeply until you see water draining from the bottom of the container. This encourages roots to grow downwards.
  • Mulch: Applying a layer of organic mulch (like straw or shredded leaves) on top of the soil can help retain moisture and regulate soil temperature.

Fertilization for Robust Growth

Container plants rely entirely on you for their nutrients. Sweet potatoes prefer a balanced approach.

  • Initial Boost: If your potting mix contains compost, you might not need to fertilize for the first few weeks.
  • Balanced Fertilizer: After about 3-4 weeks, start feeding with a balanced liquid fertilizer (e.g., 5-10-10 or 5-10-5, slightly higher in phosphorus and potassium for root development). Avoid high-nitrogen fertilizers, which promote leafy growth at the expense of tubers.
  • Frequency: Fertilize every 2-4 weeks according to product instructions. For a more sustainable how to grow purple sweet potatoes in containers approach, consider organic liquid feeds like fish emulsion or diluted compost tea.

Sunlight Requirements

Sweet potatoes are sun-worshippers!

  • Full Sun: They need at least 6-8 hours of direct sunlight per day to produce a good harvest. More sun usually means more tubers.
  • Rotate Containers: If your spot only gets partial sun at certain times, rotate your containers to maximize exposure.

Managing Vines and Foliage

Sweet potato plants are vigorous growers and will send out long vines.

  • Let Them Trail: You can let the vines trail over the sides of your containers. They look beautiful!
  • Pruning for Energy: If vines become excessively long and dense, you can trim them back. This redirects the plant’s energy into tuber production rather than endless foliage. Don’t worry, a little trim won’t hurt.
  • Vertical Growth (Optional): While not strictly necessary, you can provide a small trellis or stakes for the vines to climb if you prefer a more upright growth habit, saving space. These are excellent how to grow purple sweet potatoes in containers tips for maximizing yield and aesthetics.

Sustainable & Eco-Friendly Practices

Embrace a greener approach to your container garden.

  • Composting: Use your kitchen scraps to create nutrient-rich compost for your potting mix. This is a prime example of eco-friendly how to grow purple sweet potatoes in containers.
  • Rainwater Harvesting: Collect rainwater for irrigation; it’s free and better for your plants than chlorinated tap water.
  • Organic Pest Control: Opt for natural solutions for pests (see next section) instead of chemical sprays.

Common Problems and Solutions for Container Purple Sweet Potatoes

Even the most experienced gardeners encounter challenges. Knowing how to address common problems with how to grow purple sweet potatoes in containers will help you maintain a healthy, productive patch.

Pests to Watch Out For

While container growing reduces some pest risks, a few might still appear.

  • Aphids: Small, pear-shaped insects that cluster on new growth. They suck plant sap.
    • Solution: Spray with a strong stream of water, use insecticidal soap, or introduce beneficial insects like ladybugs.
  • Spider Mites: Tiny arachnids that cause stippling on leaves and fine webbing.
    • Solution: Increase humidity, spray with insecticidal soap or neem oil.
  • Sweet Potato Weevil: A serious pest, but less common in container growing unless you’re reusing infested soil or planting infested slips.
    • Solution: Prevention is key – use clean slips and fresh potting mix. If found, remove and destroy infested plants.

Disease Prevention

Most diseases in container sweet potatoes are related to moisture issues.

  • Fungal Issues (e.g., Root Rot): Caused by overwatering or poor drainage.
    • Solution: Ensure excellent drainage, avoid overwatering, and use a well-aerated potting mix.
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Nutritional Deficiencies

Yellowing leaves or stunted growth can indicate a nutrient issue.

  • Yellowing Lower Leaves: Often a sign of nitrogen deficiency.
    • Solution: Apply a balanced liquid fertilizer or compost tea.
  • Stunted Growth/Poor Tuber Formation: Could be due to insufficient phosphorus or potassium.
    • Solution: Use a fertilizer with a higher middle and last number (e.g., 5-10-10) or add bone meal (for phosphorus) or wood ash (for potassium) if appropriate.

No Tuber Formation

This can be frustrating, but there are usually clear reasons.

  • Too Much Nitrogen: Excessive nitrogen encourages lush leafy growth but discourages tuber development.
    • Solution: Switch to a fertilizer with lower nitrogen.
  • Insufficient Sunlight: Not enough sun means less energy for tuber production.
    • Solution: Move containers to a sunnier spot.
  • Container Too Small: If the tubers don’t have room to expand, they won’t grow.
    • Solution: Ensure you’re using adequately sized containers (15-20 gallons minimum).

Harvesting Your Purple Sweet Potato Treasure

The moment you’ve been waiting for! Harvesting your homegrown purple sweet potatoes is incredibly satisfying.

When to Harvest

Patience is a virtue when it comes to sweet potatoes.

  • Growing Period: Purple sweet potatoes typically take 90-120 days (3-4 months) from planting slips to maturity, depending on the variety and your climate.
  • Signs of Maturity: The most reliable sign is when the foliage starts to turn yellow and die back. This indicates the plant is putting all its energy into the tubers.
  • Before Frost: Always harvest before the first hard frost, as cold temperatures can damage the tubers.

The Harvesting Method

Container harvesting is much easier than in-ground!

  1. Stop Watering: Reduce watering a week or two before harvest to help cure the skins.
  2. Gently Unearth: Carefully tip the entire container onto a tarp or piece of cardboard.
  3. Locate Tubers: Gently sift through the soil to find the sweet potatoes. Be careful not to bruise or cut them, as this can reduce their storage life.
  4. Brush Off Soil: Gently brush off any excess soil. Do not wash them at this stage.

Curing for Storage

Curing is a critical step for improving flavor and extending storage life. Don’t skip it!

  1. Warm & Humid: Place the harvested sweet potatoes in a warm (85-90°F / 29-32°C), humid (85-90% relative humidity) environment for 7-10 days. A shed, garage, or even a warm room with a humidifier can work.
  2. Purpose of Curing: This process allows cuts to heal, hardens the skin, and converts starches into sugars, enhancing their sweetness and storage potential.

Storing Your Harvest

After curing, your purple sweet potatoes are ready for long-term storage.

  • Cool, Dark, Dry: Store them in a cool (55-60°F / 13-15°C), dark, and dry place. A basement, pantry, or root cellar is ideal.
  • Air Circulation: Store them in a single layer, or in breathable containers like baskets or mesh bags, to ensure good air circulation.
  • Avoid Refrigeration: Do not refrigerate sweet potatoes, as cold temperatures will cause them to develop a hard core and lose flavor.

Frequently Asked Questions About Growing Purple Sweet Potatoes in Containers

Here are some common questions gardeners ask about growing these beautiful tubers.

Can I grow purple sweet potatoes from a store-bought potato?

Yes, absolutely! As detailed in our “Propagating Slips” section, you can easily sprout slips from a healthy, organic purple sweet potato purchased from the grocery store using either the water or soil method.

How long does it take for purple sweet potatoes to grow in containers?

Typically, purple sweet potatoes take about 90-120 days (3-4 months) from the time you plant your slips until they are ready for harvest. This can vary slightly depending on the specific variety and your local climate conditions.

What kind of fertilizer is best for container sweet potatoes?

A balanced liquid fertilizer with slightly higher phosphorus and potassium (the middle and last numbers in the N-P-K ratio, like 5-10-10 or 5-10-5) is ideal. Avoid high-nitrogen fertilizers, which promote leafy growth over tuber development. Organic options like fish emulsion or compost tea are also excellent choices.

Do purple sweet potatoes need a trellis when grown in containers?

Not necessarily, but it can be beneficial. Purple sweet potatoes are vigorous vining plants. You can let the vines trail over the sides of your container, or you can provide a small trellis or stakes to encourage vertical growth. This can save space and make for a tidier plant, but it’s not crucial for tuber production.

Why are my container sweet potato leaves turning yellow?

Yellowing leaves can be a sign of several issues. If the lower leaves are yellowing, it often indicates a nitrogen deficiency. However, yellowing can also be caused by overwatering (leading to root rot), underwatering, insufficient sunlight, or even natural aging of the leaves closer to harvest time. Check your watering habits, sunlight exposure, and consider a balanced fertilizer application.

Go Forth and Grow!

Growing purple sweet potatoes in containers is a deeply satisfying experience, offering both ornamental beauty and a nutritious, delicious harvest. With the right preparation, consistent care, and a little patience, you’ll be amazed at what you can achieve in your small space.

Remember, gardening is a journey of learning and discovery. Don’t be afraid to experiment, observe your plants, and adjust your approach. Armed with these expert tips and a little bit of gardening grit, you’re well on your way to enjoying your very own vibrant, homegrown purple sweet potatoes. Happy gardening!

Rimon Chowdhury
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