Sweet potatoes, with their vibrant color and delicious flavor, are a garden staple for many. But have you ever wondered if you can simply plant an old sweet potato from your pantry and expect it to grow? The answer is a bit more nuanced than a simple yes or no. This article delves deep into the world of sweet potato propagation, exploring the possibilities, the challenges, and the best methods to successfully grow these root vegetables from existing potatoes.
Understanding Sweet Potato Propagation: Beyond the Seed
Unlike many other vegetables that are typically grown from seeds, sweet potatoes are usually propagated vegetatively. This means that new plants are grown from parts of the parent plant, rather than from seeds. While sweet potatoes do produce flowers and seeds, growing from seed is a lengthy and complex process, often resulting in unpredictable variations in the resulting plants. The more common and reliable method is to grow “slips” from the sweet potato itself.
What Are Sweet Potato Slips?
Slips are essentially sprouts that emerge from the sweet potato. These sprouts, complete with roots and leaves, are then carefully separated from the parent potato and planted in the ground to grow into new sweet potato plants. The process of growing slips is the key to successfully propagating sweet potatoes. These slips are what transform into the sprawling vines and, eventually, the delectable sweet potatoes we harvest.
The Viability of Using Old Sweet Potatoes
The good news is that you absolutely can grow sweet potatoes from old sweet potatoes! However, there are certain conditions that need to be met for success. The sweet potato needs to be healthy and relatively free from disease. An old, shriveled potato might still work, but it will be significantly less vigorous than a fresh, firm one.
Here are a few factors that influence the success rate:
- Variety: Some sweet potato varieties sprout more readily than others. Beauregard, for instance, is known for its vigorous slip production.
- Storage Conditions: Sweet potatoes that have been stored in a cool, dry, and dark place are more likely to sprout successfully.
- Potato Health: Avoid using sweet potatoes that show signs of rot, mold, or significant damage.
- Age: While an old potato can sprout, a fresher potato will generally produce more vigorous slips.
Spotting a Good Candidate
Before you dedicate time and effort to propagating a sweet potato, carefully examine it. Look for these characteristics:
- Firmness: The potato should be relatively firm to the touch, not mushy or overly soft.
- Absence of Rot: There should be no signs of rot, mold, or decay.
- Healthy Skin: The skin should be smooth and intact, without deep cuts or bruises.
- Signs of Sprouting (Optional): While not essential, small sprouts emerging from the potato’s “eyes” are a good sign.
Step-by-Step Guide to Growing Sweet Potato Slips
Growing sweet potato slips is a relatively simple process, but it requires patience and attention to detail. Here’s a breakdown of the steps involved:
Preparing the Sweet Potato
- Choose a healthy sweet potato: Select a sweet potato that meets the criteria mentioned above.
- Clean the potato: Gently wash the sweet potato with water to remove any dirt or debris. Avoid using soap or harsh chemicals.
- Cut (Optional): For larger sweet potatoes, you can cut them in half crosswise. This will encourage more slip production.
Sprouting the Sweet Potato
There are two primary methods for sprouting sweet potatoes: water propagation and soil propagation.
Water Propagation
This is the most common and visually appealing method.
- Suspend the potato: Use toothpicks to suspend the sweet potato over a jar or glass of water. The bottom half of the potato should be submerged in water, while the top half remains dry.
- Choose the right water: Use clean, room-temperature water. Change the water every few days to prevent bacterial growth.
- Provide warmth and light: Place the jar in a warm location with indirect sunlight. A sunny windowsill is ideal.
Soil Propagation
This method involves planting the sweet potato directly in soil.
- Prepare a container: Fill a pot with well-draining potting mix.
- Plant the potato: Bury the sweet potato halfway in the soil, leaving the top half exposed.
- Water thoroughly: Water the soil until it is moist but not waterlogged.
- Provide warmth and light: Place the pot in a warm location with indirect sunlight.
Nurturing the Slips
Regardless of the method you choose, it will take several weeks for slips to emerge.
- Maintain Moisture: Ensure that the water level in the jar (for water propagation) remains consistent, or that the soil remains moist (for soil propagation).
- Rotate the Potato: Rotate the sweet potato regularly to ensure even slip growth.
- Patience is Key: Don’t be discouraged if it takes a while for slips to appear. Sweet potatoes can be slow to sprout.
Harvesting and Planting the Slips
Once the slips are 6-8 inches tall and have well-developed roots, they are ready to be harvested and planted.
- Gently Remove the Slips: Carefully detach the slips from the sweet potato. For water-propagated slips, you can gently twist or cut them off. For soil-propagated slips, carefully dig them up with a small trowel.
- Prepare the Planting Bed: Choose a sunny location with well-drained soil. Amend the soil with compost or other organic matter to improve fertility.
- Plant the Slips: Plant the slips 12-18 inches apart in rows that are 3-4 feet apart. Bury the slips up to the first set of leaves.
- Water Thoroughly: Water the newly planted slips thoroughly.
- Provide Support (Optional): While not always necessary, providing support for the vines can help keep the sweet potatoes off the ground and prevent rotting.
Troubleshooting Common Issues
Even with the best preparation, you may encounter some challenges during the sweet potato propagation process. Here are some common issues and how to address them:
- No Sprouting: If your sweet potato isn’t sprouting, ensure it’s in a warm location with adequate light. Also, check the potato for signs of rot or disease. A fresher potato may be needed.
- Slips Turning Yellow: Yellowing slips can indicate overwatering or nutrient deficiency. Adjust your watering schedule and consider using a mild fertilizer.
- Rotting Potato: A rotting potato is a sign of bacterial or fungal infection. Discard the potato and start with a fresh one.
- Slow Growth: Slow slip growth can be caused by cool temperatures or insufficient sunlight. Move the potato to a warmer, sunnier location.
Optimizing Your Sweet Potato Harvest
Once your sweet potato plants are established, proper care is essential for a bountiful harvest.
- Watering: Water regularly, especially during dry periods. Sweet potatoes need consistent moisture to thrive.
- Weeding: Keep the planting bed free of weeds, which can compete with the sweet potatoes for nutrients and water.
- Fertilizing: Side-dress the plants with a balanced fertilizer a few weeks after planting.
- Pest Control: Monitor the plants for pests, such as aphids and sweet potato weevils. Take appropriate measures to control them.
Harvesting Sweet Potatoes:
Sweet potatoes are typically ready to harvest in the fall, about 90-120 days after planting. The leaves will start to turn yellow and the vines will begin to die back. Carefully dig up the sweet potatoes, being careful not to damage them.
Curing Sweet Potatoes:
After harvesting, sweet potatoes need to be cured. Curing involves storing the sweet potatoes in a warm, humid location (80-85°F and 85-90% humidity) for 7-10 days. This process helps to heal any wounds and improve the flavor and storage life of the sweet potatoes. After curing, store the sweet potatoes in a cool, dry, and dark place.
Conclusion: Embracing the Sweet Potato Growing Journey
Growing sweet potatoes from old potatoes is a rewarding and sustainable gardening practice. While it requires patience and attention to detail, the satisfaction of harvesting your own homegrown sweet potatoes is well worth the effort. By understanding the principles of sweet potato propagation and following the steps outlined in this article, you can successfully grow these delicious and nutritious root vegetables in your own backyard. So, next time you find an old sweet potato in your pantry, don’t discard it – give it a new life and embark on a sweet potato growing adventure!
Can any potato be used to grow sweet potatoes?
It’s crucial to understand that you cannot grow sweet potatoes from regular potatoes (like Russets or Yukon Golds). Sweet potatoes and regular potatoes belong to completely different plant families. Regular potatoes are part of the nightshade family (Solanaceae), while sweet potatoes are in the morning glory family (Convolvulaceae). Therefore, using a regular potato will simply result in the growth of potato plants, not sweet potatoes.
To grow sweet potatoes, you need a sweet potato itself. Look for organic sweet potatoes at the grocery store, as conventionally grown ones are often treated to prevent sprouting. You can also purchase certified disease-free sweet potato slips (sprouts) from a reputable gardening supplier.
How do you actually grow slips from a sweet potato?
Growing slips involves suspending a sweet potato in water or partially burying it in moist soil. For the water method, use toothpicks to suspend the sweet potato halfway in a jar or glass of water, ensuring the bottom end is submerged. Place it in a warm, sunny location. For the soil method, bury the sweet potato halfway in a container filled with moist potting mix, again placing it in a warm, sunny area.
Within a few weeks, sprouts (slips) will emerge from the sweet potato. Once the slips reach about 6-8 inches in length and have developed their own roots, they can be carefully removed from the sweet potato and planted in your garden. Avoid ripping the slips; gently twist or cut them off, ensuring you don’t damage the parent sweet potato too much.
What is the best time of year to start growing sweet potato slips?
The best time to start growing sweet potato slips is approximately 6-8 weeks before the last expected frost in your area. This gives the slips enough time to develop into strong seedlings ready for transplanting outdoors once the soil has warmed up sufficiently. Check your local frost dates to determine the ideal starting time.
Starting the slips indoors allows you to get a head start on the growing season, especially in regions with shorter summers. Sweet potatoes require a long growing season (100-140 days) to mature fully. By starting slips early, you increase your chances of harvesting a good crop of sweet potatoes.
What kind of soil is best for growing sweet potatoes?
Sweet potatoes thrive in well-drained, sandy loam soil. Good drainage is essential to prevent the roots from rotting. Avoid heavy clay soils, as they retain too much moisture and can hinder tuber development. If you have clay soil, amend it with organic matter like compost and sand to improve drainage and aeration.
The ideal soil pH for sweet potatoes is between 6.0 and 6.5. Conduct a soil test to determine your soil’s pH level and adjust it accordingly using lime to raise the pH or sulfur to lower it. Amending the soil with well-rotted manure or compost before planting will also provide essential nutrients for healthy growth.
How much sun do sweet potatoes need to grow properly?
Sweet potatoes require at least 6-8 hours of direct sunlight per day to thrive. Adequate sunlight is crucial for photosynthesis, which fuels the growth of the vines and the development of the sweet potato tubers underground. Planting in a sunny location will result in a higher yield of larger, more flavorful sweet potatoes.
If you are growing sweet potatoes in a container, make sure to place it in a spot that receives full sun throughout the day. If you live in a particularly hot climate, providing some afternoon shade during the hottest part of the day can help prevent the leaves from scorching. Insufficient sunlight will result in weak vines and small, underdeveloped tubers.
How often should I water sweet potatoes?
Sweet potatoes require consistent moisture, especially during the initial stages of growth after transplanting the slips. Water thoroughly when the top inch of soil feels dry to the touch. Avoid overwatering, as this can lead to root rot. Once the vines are established, sweet potatoes are relatively drought-tolerant.
During periods of prolonged drought, it’s important to provide supplemental watering to prevent the tubers from becoming stressed and stunted. Water deeply but infrequently, aiming to saturate the soil around the roots. Mulching around the plants with organic matter like straw or wood chips can help retain moisture in the soil and reduce the need for frequent watering.
Are there any common pests or diseases that affect sweet potatoes?
Yes, sweet potatoes can be susceptible to certain pests and diseases. Common pests include sweet potato weevils, flea beetles, and wireworms. Diseases can include stem rot, scurf, and black rot. Inspect your plants regularly for signs of infestation or disease.
Implementing preventative measures is key. Use certified disease-free slips, practice crop rotation, and maintain good soil drainage. If you detect pests, consider using organic pest control methods such as neem oil or insecticidal soap. For diseases, remove and destroy infected plants promptly to prevent the spread of the disease.