Growing sweet potatoes is surprisingly easy, even for a beginner gardener. Just make sure they receive full sunlight for 6-8 hours each day, and plant them in loose, well-draining soil with plenty of organic matter. They thrive in warm weather, needing around 90-120 days to mature with soil temperatures over 60°F (16°C). Regular watering, about 1-2 inches per week, is key, but be careful to avoid overwatering.
Table of Contents
Why are Sweet Potatoes an excellent Survival Food?
Sweet potatoes are considered an excellent survival food for several reasons, making them a valuable resource in long-term survival situations. Their combination of nutritional value, ease of cultivation, long storage life, and versatility make sweet potatoes a dependable food for survival scenarios.
Nutrient-Dense Food
Sweet potatoes are a great source of complex carbohydrates, providing sustained energy essential for physical endurance.
Also, they are packed with important nutrients like vitamin A (beta-carotene), vitamin C, potassium, and manganese. These nutrients help boost immunity, maintain vision, and regulate bodily functions. They’re a great whole food for managing body weight.
Moreover, high fiber content supports digestive health and helps with feeling fuller for longer, which is critical in survival situations where food may be scarce.
Easy to Grow and Hardy
Sweet potatoes can grow in a wide variety of climates and soil conditions, making them a versatile crop. They are drought-resistant and can thrive in poor soil, requiring relatively low maintenance. A small planting can produce a large yield of sweet potatoes, providing a reliable source of food for extended periods.
Long Shelf Life
When cured properly, sweet potatoes can last for several months in storage without refrigeration, making them ideal for stockpiling. Their hard skin protects them from spoiling quickly.
Versatility in Cooking
Sweet potatoes can be boiled, baked, roasted, or even eaten raw (though raw consumption is not as common). This versatility allows for variety in diet, even in limited circumstances.
Also, they can be dehydrated, powdered, or canned, extending their usability.
Both Root and Leaves are Edible
In addition to the root, sweet potato leaves are also edible and nutritious. They provide additional vitamins and minerals, particularly when other green vegetables are unavailable.
Caloric Density
Sweet potatoes are relatively high in calories compared to many other vegetables, making them an efficient food source for energy in survival situations. Boiled sweet potatoes have around 80 calories per 100 grams. A medium plant provides 115 calories.[1]
How many calories per Square Foot?
The caloric yield from growing sweet potatoes can vary based on factors like growing conditions, soil quality, climate, and gardening practices. However, we can estimate the number of calories you might harvest per square foot.
Field Growing
Sweet potatoes grown in the field typically yield higher than in containers due to more space and optimal growing conditions.
Sweet potatoes typically yield about 1–2 pounds per square foot in field cultivation and they provide around 80 calories per 100g or 800 calories per kg. This translates to roughly 350 calories per pound.
So, the caloric yield is 350-700 calories/square foot.
Container Growing
Container growing often results in lower yields compared to field growing because of space constraints and limited soil volume. The yield in containers is typically around 0.5–1 pound per square foot, depending on container size, depth, and growing conditions.
The caloric Yield is 175-350 calories/square foot.
How many days does it take to grow Sweet Potatoes?
You start by producing slips from a mature sweet potato. Place the sweet potato in water or soil, and it will sprout within 2–4 weeks. Each slip can then be separated and planted.
This process is usually done indoors before the growing season, as it takes some time for the slips to develop.
Once the slips are 6–12 inches long and have several leaves, they are ready to be transplanted.
Sweet potatoes typically take 90–120 days to grow to maturity after planting the slips, depending on the variety and climate.
Sweet potatoes take about 120–150 days from starting the slips to harvesting mature tubers.
- Slips development: 2–4 weeks.
- Growing from planting to harvest: 90–120 days.
Are Leaves & Flowers Edible?
Yes, sweet potato leaves are edible and are actually a nutritious addition to meals. The leaves are commonly consumed in various parts of the world, particularly in Africa, Asia, and the Pacific Islands.
Nutritional Benefits
Vitamins: Rich in vitamins A, C, and B-complex.
Minerals: Contain calcium, iron, and potassium.
Antioxidants: High in antioxidants like polyphenols, which can help reduce inflammation.
Preparation
Sweet potato leaves are often sautéed, steamed, boiled, or added to soups and stews. They have a slightly bitter, earthy taste, similar to spinach, and become tender when cooked.
Sweet potato flowers are much less commonly consumed, but they are not known to be toxic. However, they are not typically eaten because they are relatively rare and small, and most of the plant’s value lies in the tubers and leaves.
If you do find the flowers and choose to eat them, there is no documented danger, but they might not be as palatable or useful in cooking as other parts of the plant.
Are They Dangerous or Poisonous?
Sweet potato leaves are not poisonous and are perfectly safe to eat. There is no evidence that flowers are poisonous as well.
However, it’s important not to confuse sweet potatoes (Ipomoea batatas) with potatoes (Solanum tuberosum). The leaves and stems of regular potatoes are toxic due to the presence of solanine, a harmful compound, but sweet potato plants do not contain this toxin.[2,3]
Where can I Grow Sweet Potatoes?
Sweet potatoes thrive in warm climates and are sensitive to cold, so their growing season depends heavily on the region’s climate and USDA hardiness zone.
Sweet potatoes grow best in USDA Hardiness Zones 8-11, where the temperatures stay warm for an extended period, but they can also be grown in cooler zones with some adjustments.
Zones 8-11 provide the long, warm growing season that sweet potatoes require (90–120 days of warm weather). Southern states in the U.S. like Florida, Texas, and parts of California fall into these zones.
Zones 7: You can grow sweet potatoes in Zone 7, but you may need to start slips indoors or use black plastic to warm the soil more quickly in the spring. The growing season is slightly shorter, so selecting quick-maturing varieties can help.
Zones 6 and Below: Growing sweet potatoes is more challenging in these zones, but it’s possible if you use techniques like starting slips indoors, using row covers, or growing them in containers that can be moved indoors when temperatures drop. In these cooler zones, you should aim to grow varieties that mature more quickly (closer to 90 days).
Can I Grow them in the Mediterranean Area?
Yes, you can grow sweet potatoes in the Mediterranean region, as the climate is well-suited for their cultivation. The Mediterranean climate, characterized by mild winters and hot, dry summers, is ideal for growing sweet potatoes, which require warmth and a long growing season (90–120 days).
When to Grow Sweet Potatoes in the Mediterranean?
Sweet potatoes need to be planted after the last frost and when the soil has warmed to at least 60°F (16°C).
Sweet potatoes are typically planted between April and May in most Mediterranean areas. Sweet potatoes can be harvested about 90-120 days after planting, which typically falls between August and October.
Tip
Choose varieties that are heat-tolerant, as Mediterranean summers can get very warm. Some popular varieties include ‘Beauregard,’ ‘Covington,’ or ‘Jewel.’
Are they a traditional Mediterranean Crop?
No, sweet potatoes are not a traditional Mediterranean crop. They are native to Central and South America and were introduced to other parts of the world after European exploration in the 15th and 16th centuries.
Although sweet potatoes are not historically Mediterranean, they are increasingly grown and consumed in Mediterranean countries due to their adaptability to the climate. Their nutritional benefits and versatility have made them more popular in modern Mediterranean diets, particularly for those looking to diversify their vegetable intake.
Know the Plant
The sweet potato is a warm-season, perennial plant, typically grown as an annual for its edible tuberous roots.
It is a vine plant with trailing stems that can grow up to 3-6 feet long. The vines spread along the ground, and the plant has large, heart-shaped leaves.
Sweet potato flowers resemble morning glory flowers (to which they are related), with funnel-shaped blossoms. The flowers are usually light purple or white with a purple throat, but they don’t appear frequently in many cultivated varieties.
The sweet potato tubers (the edible part) form underground. These tubers are swollen root structures that store carbohydrates and nutrients.
How Deep are the Roots?
The root system extends about 6–12 inches (15–30 cm) deep into the soil. However, sweet potatoes are shallow-rooted, meaning that most of their feeding roots stay relatively close to the surface.
Sweet potatoes can spread 12–18 inches (30–45 cm) laterally, meaning they take up significant ground space even though they don’t require deep soil.
Tubers form in clusters around the base of the plant, just below the soil surface.
Pollination
Sweet potato flowers are self-fertile, meaning that they can pollinate themselves. Each flower contains both male and female reproductive organs (stamens and pistils). Insects, particularly bees (especially honeybees and carpenter bees), are the primary pollinators when flowers are present.
Since sweet potato flowers are not always common in some varieties, cross-pollination isn’t typically a major factor in root production.
Tips to Grow Healthy Sweet Potatoes
Temperature
Sweet potatoes are a warm-weather crop and are highly sensitive to cold. Ensuring the right temperatures at various growth stages is essential for their successful cultivation.
Slips (seedlings)
Ideal Temperature: 75–85°F (24–29°C). This temperature range is optimal for sprouting slips from mature sweet potatoes. The process takes about 2–4 weeks to develop slips in these warm conditions.
Hardening Off the Slips
Before transplanting the sweet potato slips into the field or garden, they need to be hardened off to acclimate to outdoor conditions. Start exposing the slips to outdoor conditions when daytime temperatures consistently reach 60–70°F (15–21°C).
Gradually increase their time outside over a period of 7–10 days, starting with a few hours in partial shade and slowly increasing sun exposure.
Transplanting Slips
Transplant slips when the soil temperature reaches 60–70°F (16–21°C) or higher. Cold soil can stunt root development and cause stress to the plants.
The ideal air temperature for transplanting is 65–85°F (18–29°C).
Transplant after the last frost when nighttime temperatures are consistently above 55°F (13°C) and daytime temperatures are warm.
Growing Season
During the growing season, sweet potatoes thrive in warm, sunny conditions:
The optimal growing temperature is 75–95°F (24–35°C). They can tolerate short periods of higher temperatures (over 95°F or 35°C), but extreme heat stress may affect tuber quality.
Harvest Time
Sweet potatoes should be harvested before frost sets in, as frost can damage the vines and tubers. The optimal harvest temperature is when daytime temperatures are still around 65–75°F (18–24°C).
You want to plant sweet potatoes after the last frost of spring when the soil has warmed to at least 60°F (16°C).
Propagation
Sweet potatoes are primarily propagated vegetatively through slips (sprouts from mature tubers) rather than seeds. This method ensures consistent, high-quality tubers since seeds can produce genetically variable plants.
Slips are young shoots that grow from mature sweet potatoes. These slips are then transplanted to the field or garden to grow new sweet potato plants.
How to Start Slips?
Select healthy, disease-free sweet potatoes (preferably from certified seed stock) and place them in warm, moist conditions.
You can either place half of the tuber in a jar of water with toothpicks holding it above the waterline. Within 2–4 weeks, slips will begin to sprout from the tuber.
Or you could place the sweet potato tuber in moist soil. Partially bury the tuber in loose, sandy soil.
Additionally, if you leave a sweet potato in a dark, warm, and humid place, it can naturally begin to produce sprouts without any additional help. This is similar to what happens when potatoes sprout in your pantry. No wonder why this is my favorite method for growing slips…
The ideal temperature range for sweet potatoes to sprout slips is between 70–85°F (21–29°C).
While slips can form in the dark, they will be pale and weak if they grow for too long without light. As soon as the slips emerge, they need to be moved to a place with indirect sunlight or fluorescent light so they can become healthy, green, and strong.
Slips will sprout from the tuber. Once they are about 6–12 inches long, they can be cut off and transplanted.
Transplanting Slips
Each slip is gently pulled or cut from the sweet potato. The slips are then planted directly in the garden or container. Once transplanted, the slips will form their own root systems and begin to produce new sweet potato tubers.
Are Sweet Potatoes from the Supermarket Good for Propagation?
In many cases, supermarket sweet potatoes will sprout and produce slips just as effectively as those from a seed supplier. This can be a cost-effective way to start growing sweet potatoes.
But keep in mind that many commercial sweet potatoes are treated with a chemical sprout inhibitor (such as chlorpropham) to prevent them from sprouting in storage. This makes it difficult for them to produce slips. You can still try, but success rates may be low.
Moreover, supermarket sweet potatoes are often selected for shipping and storage qualities, not necessarily for their taste or adaptability to different climates. You may not know the variety you’re growing, which could impact the growing season, yield, and flavor.
Look for organic sweet potatoes, as these are less likely to be treated with sprout inhibitors. Rinse them well to help remove any chemical treatments before attempting to sprout them.
For consistent success, it’s recommended to use certified seed sweet potatoes purchased from a garden center or seed supplier.
Seed-based propagation is uncommon due to the high variability in the offspring.
Tips to transplant succefully Slips
Timing of Transplanting
Transplant after the last frost. Sweet potatoes and slips in particular are highly sensitive to cold.
Wait for 4-6 true leaves. Ensure the slips are well-developed, typically 6–12 inches tall with 4-6 true leaves and healthy roots before transplanting.
Soil Preparation
Sweet potatoes thrive in loose, well-drained, sandy loam soil. They do not do well in heavy, clay-like soils, as this can lead to waterlogging and rotting.
Before planting, amend the soil with compost or well-rotted manure to improve its nutrient content and drainage. Sweet potatoes need fertile soil to grow large tubers.
Spacing Between Slips
Proper spacing allows room for the sweet potatoes to grow underground tubers and prevents overcrowding.
Plant slips 12–18 inches (30–45 cm) apart in the row. This gives the plants enough room to develop healthy vines and large tubers.
Leave 3–4 feet (90–120 cm) between rows. Sweet potatoes have a sprawling vine growth habit, so adequate row spacing prevents the vines from tangling and competing for sunlight.
Planting Depth
Bury each slip about 2–3 inches (5–7 cm) deep in the soil, making sure that the leaves are above the soil and the roots are well-covered. This encourages strong root development.
Watering After Transplanting
After transplanting the slips, water them thoroughly to help them establish in their new environment.
Keep the soil consistently moist (but not waterlogged) for the first 2–3 weeks as the slips develop strong roots. Sweet potatoes are somewhat drought-tolerant once established but need good moisture in the early stages.
Mulching
Apply a layer of organic mulch (such as straw or shredded leaves) around the plants. This helps retain soil moisture, suppresses weeds, and keeps the soil temperature consistent.
| Category | Key Tips |
|---|---|
| Timing | Transplant after the last frost when soil reaches at least 60°F (16°C). |
| Slip Readiness | Slips should be 6–12 inches tall with 4-6 true leaves and developed roots. |
| Soil Preparation | Use loose, well-drained soil, amended with compost or organic matter. |
| In-Row Spacing | Space slips 12–18 inches (30–45 cm) apart in the row. |
| Row Spacing | Leave 3–4 feet (90–120 cm) between rows for sprawling vines. |
| Planting Depth | Bury slips 2–3 inches (5–7 cm) deep, with leaves above the soil. |
| Watering | Water immediately after transplanting; keep soil moist (but not waterlogged) during early growth. |
| Mulching | Apply organic mulch to conserve moisture, suppress weeds, and regulate soil temperature. |
| Sunlight | Ensure 6–8 hours of direct sunlight per day. |
| Fertilizing | Use low-nitrogen fertilizer; focus on potassium and phosphorus for tuber development. |
Sunlight
Sweet potatoes need 6–8 hours of direct sunlight per day for healthy growth. Full sun is essential to promote vigorous vine growth and good tuber development.
Sweet potatoes are heat-tolerant, and they generally do well in warm, sunny climates. They thrive in temperatures between 75–95°F (24–35°C) during the growing season, which makes them a good fit for Mediterranean regions with warm summers.
Excessive Sunlight
In many areas like the Mediterranean region, during the peak of summer, sunlight can be particularly intense, and temperatures can frequently exceed 95°F (35°C). This can lead to heat stress.
Excessive heat and strong, direct sunlight can cause heat stress, particularly for the leaves. While the sweet potato vines themselves are relatively tolerant of heat, prolonged exposure to very high temperatures can slow down tuber formation.
Also, high heat increases evaporation and can lead to water stress, particularly in sandy or fast-draining soils. Sweet potatoes need consistent moisture during the growing season.
Thus, shade nets may be beneficial in very hot Mediterranean climates to help mitigate the effects of extreme heat and prevent sunscald or heat stress.
You may need to apply them during the peak summer months (e.g., July and August), when temperatures are consistently above 95°F (35°C) and the sun is strongest. Check your plants for signs of heat stress, such as wilting, leaf scorch, or reduced growth.
Use 30–40% shade cloth. This level of shading provides protection from excessive sunlight while still allowing enough light for photosynthesis. [BUY ON AMAZON]
Ensure the nets are well-ventilated to avoid trapping too much heat, which could further stress the plants.
What type of Soil is best?
Sweet potatoes grow best in loose, well-drained soil that allows the roots to expand easily and avoids waterlogging. This type of soil ensures that the tubers can develop without obstruction, resulting in large, healthy sweet potatoes.
The ideal soil for sweet potatoes is a sandy loam, as it:
- has a good balance of sand, silt, and clay.
- is loose and easy for the roots to penetrate.
- drains well but retains enough moisture for the plants.
Sweet potatoes prefer soil with a pH of 5.5 to 6.5, which is slightly acidic to neutral. You can adjust soil pH by adding lime if the soil is too acidic or sulfur if the soil is too alkaline.
Tolerated Soil Types
Sweet potatoes are relatively adaptable and can tolerate a range of soil types, but some soils may require modification to optimize growing conditions.
Clay Soils
Heavy clay soils are generally not ideal for sweet potatoes because they are dense and poorly drained. The compact nature of clay soil can restrict root expansion and lead to waterlogging, which can cause the tubers to rot.
If you have clay soil, amend it by adding organic matter (compost, sand, or fine bark) to loosen the soil and improve drainage.
Sandy Soils
Sweet potatoes can tolerate sandy soil, but pure sand may drain too quickly and not retain enough nutrients or moisture. To make sandy soil more suitable, add organic matter to help with water retention and improve nutrient availability.
Loamy Soil
Loamy soil, a mix of sand, silt, and clay, is generally very fertile and easy to work with, making it an excellent choice for sweet potatoes. Ensure it is loose enough for root expansion and drains well.
Organic Fertilizers
Avoid fertilizers high in nitrogen, as this can promote excessive vine growth at the expense of tuber development. Instead, opt for a balanced fertilizer or one with higher potassium and phosphorus levels to encourage root formation. Sweet potatoes benefit from organic fertilizers and soil amendments that promote healthy root development without encouraging excessive vine growth.
Compost
Compost provides a balanced supply of nutrients (nitrogen, phosphorus, potassium, and trace minerals) and improves soil structure, water retention, and drainage. [BUY HERE]
Incorporate 2–3 inches of compost into the soil a few weeks before transplanting slips to improve soil fertility and organic matter content.
Also, you could add compost as a side dressing around the base of the plants during the growing season, particularly if the plants show signs of nutrient deficiency.
Well-Rotted Manure
Manure, especially well-rotted cow or horse manure, adds nitrogen, potassium, and phosphorus to the soil while improving its organic content.
Apply a layer of manure and mix it into the soil several weeks before planting to allow it to break down. Fresh manure can be too high in nitrogen, which encourages excessive vine growth rather than tuber development. Make sure it’s well-composted before use.
Bone Meal
Bone meal is an excellent source of phosphorus, which is crucial for root and tuber development. Phosphorus promotes strong root systems and improves the quality of tubers.
Incorporate bone meal into the soil when preparing the planting area. Phosphorus takes time to break down and become available to plants. You can also add bone meal to the planting hole when transplanting slips.
Wood Ash
Wood ash is a natural source of potassium, which is essential for tuber development and disease resistance. Potassium strengthens plant tissues and helps improve yields.
Sprinkle wood ash on the soil and mix it in before planting. You can add wood ash as a side dressing during the growing season to ensure the plants have enough potassium, but use it sparingly to avoid raising the soil pH too much.
Alfalfa Meal
Alfalfa meal is rich in nitrogen and also contains trace minerals and growth hormones that stimulate root growth. [BUY ON AMAZON]
Mix alfalfa meal into the soil a few weeks before planting to provide a slow-release source of nitrogen. Use as a side dressing if plants show signs of nitrogen deficiency, but be cautious not to over-apply and promote excess vine growth over tuber formation.
Fish Emulsion
Fish emulsion is a fast-acting organic fertilizer rich in nitrogen, phosphorus, and potassium. It is excellent for promoting overall plant health and is gentle enough to be used regularly. It’s the fertilizer that I use the most…
Dilute fish emulsion and apply as a foliar spray or water-in around the plants during the growing season, especially if plants look pale or growth is stunted. [BUY HERE]
Seaweed/Kelp Meal
Seaweed or kelp meal contains trace minerals, potassium, and growth hormones that promote healthy root development and improve resistance to stress. Use as a side dressing or foliar spray during the growing season. It helps the plants handle stress from heat, drought, or pests.
Soil Amendments
Vermicompost
Vermicompost is a nutrient-rich compost produced by earthworms. It improves soil structure, adds beneficial microbes, and enhances nutrient availability. [BUY HERE]
Incorporate vermicompost into the soil during bed preparation. Also, you could add it as a side dressing or top dressing throughout the season. Vermicompost is the dark gold for gardeners![3]
Green Manure (Cover Crops)
Green manure crops (such as clover or vetch) are grown and then tilled into the soil to improve organic matter, nitrogen levels, and soil structure. Plant a cover crop in the off-season, then till it into the soil a few weeks before planting sweet potatoes.
| Stage | Fertilizers/Amendments | Details |
|---|---|---|
| Before Planting (Soil Prep) | – Compost – Well-rotted manure – Bone meal – Wood ash – Alfalfa meal | Mix organic matter into the soil a few weeks before planting to improve fertility and structure. |
| At Transplanting | – Bone meal – Compost – Vermicompost | Add a handful of bone meal and compost to the transplant hole to promote strong root development. |
| During Growing Season | – Fish emulsion – Kelp meal – Compost – Wood ash (light application) | Side-dress with compost or apply diluted fish emulsion or kelp meal as needed to support healthy plant growth. |
| Mid-Growing Season | – Alfalfa meal (if needed) | Use only if nitrogen deficiency is visible (yellowing leaves), but avoid excess to prevent too much vine growth. |
Water needs
Young slips require consistent moisture as they establish their root systems.
Immediately water the slips after transplanting to help them establish. Keep the soil consistently moist (but not soggy) for the first 1–2 weeks. Water deeply 2–3 times per week, depending on soil type and weather. The goal is to keep the top few inches of soil moist while the slips develop roots.
Provide 1–2 inches (2.5–5 cm) of water per week during this initial establishment phase.
Sweet potato slips need consistent moisture during the first 2–4 weeks after transplanting. Ensure the soil remains evenly moist but not waterlogged. Use a moisture meter or your finger to check that the soil is moist about 1 inch (2.5 cm) down.
During Active Growth
Once sweet potato plants are established (around 4–6 weeks after transplanting), they become more drought-tolerant, and watering practices can change.
After the plants are well-established, reduce watering to about once a week or when the top 1–2 inches (2.5–5 cm) of soil are dry.
Water deeply to encourage the tubers to grow larger. Deep watering ensures moisture reaches the lower root zone, helping the sweet potatoes grow bigger and healthier.
Sweet potatoes generally require 1–1.5 inches (2.5–4 cm) of water per week, depending on climate and soil type.
During the Tuber-Forming Stage
As the sweet potato plants begin forming tubers (about 40–60 days after transplanting), they still need regular watering, but avoid overwatering as this can lead to root rot. Continue providing about 1 inch (2.5 cm) of water per week, but be careful not to water too frequently.
Mulching with organic material like straw helps retain moisture and keeps the soil temperature stable, reducing the need for frequent watering.
In the final weeks before harvest, reduce watering to encourage the tubers to mature.
Reduce watering about 2–3 weeks before harvest to prevent the tubers from splitting and to allow them to cure in the ground. This also helps reduce the risk of rot during storage.
Let the soil dry out slightly but don’t allow it to become completely dry or cracked. This allows the skins of the sweet potatoes to toughen up, which improves storage quality.
Avoid frequent shallow watering, which can promote shallow roots and lead to poor tuber development.
When to Water?
Watering early in the morning reduces evaporation and allows plants to take up moisture during the heat of the day.
Signs That Sweet Potatoes Need Water
If you notice the leaves wilting during hot days, check the soil moisture. If it’s dry, water immediately. Moreover, if the soil is dry and cracking, it indicates the need for water. Stunted or slow-growing plants may indicate water stress as well.
Do they need Pruning?
Sweet potatoes do not typically require pruning, and in most cases, it is not necessary to cut the vines. The sprawling vines of sweet potatoes help the plant gather sunlight and support tuber development.
Allowing the vines to grow and spread freely often results in better tuber growth. Cutting back the vines can reduce the amount of energy the plant generates, which could affect the size and yield of the sweet potatoes.
In cases where the vines are overgrowing other garden plants, you can trim them back slightly to keep the sweet potatoes contained. This is more for garden management than plant health.
Also, if the vines are densely tangled, lightly pruning or trimming some vines can improve air circulation, helping reduce the risk of fungal diseases. However, keep pruning minimal, as too much can stress the plant and reduce yields.
Avoid cutting vines too close to harvest time, as this can interfere with tuber development. Sweet potato vines naturally die back when the tubers are mature, which is a sign that harvest time is approaching.
Some gardeners believe that cutting back sweet potato vines will stimulate more tuber growth, but this is not supported by evidence.
Harvesting Vine Tips
The tender tips of sweet potato vines are edible and can be harvested as a vegetable (similar to spinach or other greens). If you harvest vine tips, do so sparingly, so it doesn’t affect the overall growth of the plant.
Do they require Thining?
Sweet potatoes typically do not require thinning. Once the slips are planted at the correct spacing, you do not need to thin them. The plants will naturally spread out, and there won’t be crowding like there might be with direct-sown seeds.
Unlike crops that are sown densely and require thinning to reduce competition (such as radishes or lettuce), sweet potatoes are planted individually as slips, so each plant already has its own space.
Support for Vines
Sweet potato vines do not require support, such as a trellis or other structure, and can be allowed to spread on the ground naturally. Sweet potatoes are typically grown as a sprawling ground vine. The vines are not climbers like pole beans or cucumbers, so they do not naturally climb or benefit from a trellis.
In fact, the vines help shade the soil, which reduces water evaporation and helps retain soil moisture—beneficial for tuber formation. Additionally, the large surface area covered by the vines helps the plant capture more sunlight, which is essential for photosynthesis and tuber development.
As the vines spread, they help suppress weeds by shading the soil, reducing competition from other plants.
When can I use a Trellis?
While not necessary, some gardeners choose to grow sweet potato vines vertically using a trellis or other support system. In small gardens or urban areas where space is limited, some gardeners may use vertical support to manage the vines. Hence, vertical growth can allow for more plants to be grown in a smaller area.
Furthermore, some people prefer the appearance of a more organized garden, though it may take extra effort.
Raising the vines off the ground may also help reduce certain pests and diseases, but this is typically not an issue with ground-growing vines when properly managed.
Moreover, by training sweet potato vines to grow vertically, you can create shade for nearby plants, reducing their exposure to direct sunlight during the hottest parts of the day.
For instance:
- Lettuce thrives in cooler temperatures and can bolt (go to seed) in excessive heat. Shade from sweet potato vines can help keep lettuce plants cooler.
- Spinach also prefers cooler conditions and can benefit from shade to prolong its growing season.
- Kale: while more heat-tolerant than lettuce, kale can still benefit from some shade, especially in very hot climates.
- Radishes can become bitter and woody if grown in too much heat, so shade can help maintain their flavor.
- Swiss Chard tolerates some heat but prefers cooler conditions. Shade can help prevent stress and promote better growth.
- Herbs (e.g., Cilantro, Parsley) can bolt in the heat. Providing shade can help extend their growing season.
Consider Timing
As sweet potato vines grow, they may take some time to establish. Plan to plant them early enough to provide shade during peak summer heat.
When to Harvest?
Harvesting sweet potatoes at the right time ensures the best flavor, texture, and storage quality. Sweet potatoes are ready to harvest when the tubers have reached maturity, typically 90 to 120 days after planting, depending on the variety.
Check the expected maturity time for the variety you planted (usually on the seed packet).
One common sign of maturity is when the leaves and vines start to yellow and die back. This occurs naturally as the plant focuses energy on the tubers. Once the vines stop growing aggressively, the sweet potatoes are likely ready for harvest.
About 100 days after planting, gently dig up one or two sweet potato plants to check the size and development of the tubers.
If the sweet potatoes have reached a good size, they are ready for harvest. If they are still small, give them more time. Mature tubers should be large enough to eat (typically 2–3 inches in diameter or more). The skin of a mature sweet potato should be firm and not peel easily when rubbed.
If some sweet potatoes are still small when you dig up the plant, you can leave them in the ground a bit longer to grow, as long as the vines are still healthy and there’s no threat of frost.
Sweet potatoes are sensitive to frost. It’s crucial to harvest all sweet potatoes before the first frost. Frost can damage the tubers and cause them to rot, even if they’re still underground. If frost is expected, harvest the sweet potatoes immediately, even if they haven’t reached full maturity.
How to Harvest Sweet Potatoes?
When harvesting, take care to avoid damaging the tubers. Damaged tubers are prone to rotting during storage.
Use a garden fork or spade to gently loosen the soil around the plants, starting about 12–18 inches away from the main stem to avoid damaging the tubers.
Carefully dig down and around the plants to expose the sweet potatoes. Sweet potatoes grow relatively shallow (6–12 inches deep), but the vines can spread out, so make sure to dig wide.
Gently lift the tubers from the soil by hand. Be cautious, as sweet potatoes bruise easily, and damaged tubers won’t store well.
Lightly brush off any loose dirt from the tubers, but avoid washing them until you’re ready to cure or eat them. Washing can introduce moisture, which may cause the tubers to rot.
Tips
Harvesting when the soil is dry will make it easier to dig up the tubers and reduce the chance of rot from wet soil. In the weeks leading up to harvest, avoid overwatering. Too much moisture can cause the tubers to split.
Store Tips
Best Practices After Harvest
Curing sweet potatoes allows the skins to toughen and enhances their flavor by converting starches to sugars. Proper curing is essential for long-term storage.
Place the sweet potatoes in a warm, humid environment. Ideal conditions are around 80–85°F (26–29°C) and 85–90% humidity for 7–10 days. You can cure sweet potatoes in a warm garage, a greenhouse, or indoors with a humidifier if necessary. Keep them out of direct sunlight.
How to Store?
Once cured, store the sweet potatoes in a cool, dry place (ideally 55–60°F / 13–16°C) with good ventilation.
Properly cured and stored sweet potatoes can last for 6 months or more.
Common Pests & Diseases
Sweet potatoes are vulnerable to various pests and diseases, including rodents like mice that are attracted to their nutritious tubers. The key to preventing damage is proactive garden management, including crop rotation, using certified disease-free slips, and maintaining clean, healthy soil.
Common Pests
Sweet Potato Weevils
One of the most destructive pests of sweet potatoes, sweet potato weevils (Cylas formicarius) are small (1/4-inch long), dark insects with a characteristic long snout. Larvae bore into the tubers, causing dark, dry areas and reducing the tuber’s quality. They also damage the vines and leaves.
Prevention: Use certified disease-free slips. Rotate crops and avoid planting sweet potatoes in the same spot year after year. Destroy infected plants and control nearby weeds.
Flea Beetles
Tiny beetles that jump when disturbed, usually black or brown. Flea beetles (Systena blanda) chew small, round holes in leaves, resulting in a “shot-hole” appearance. While foliage damage is common, it rarely affects tuber production significantly.
Prevention: Use row covers early in the season. Mulching can help deter flea beetles.
Wireworms
The larvae of click beetles, which are long, thin, and pale brown. Wireworms (Agriotes spp.) tunnel into tubers, leaving holes that invite rot and decay.
Prevention: Avoid planting in areas recently used for grasses or cereal crops. Use crop rotation and avoid wet soils.
Whiteflies
Tiny, winged insects (Bemisia tabaci) that suck sap from plants, usually found on the underside of leaves. Infestation weakens plants, causes yellowing, and leads to stunted growth.
Prevention: Use insecticidal soap or neem oil. Introduce beneficial insects like ladybugs.
Aphids
Small, soft-bodied insects that suck sap from plant tissues. Aphids (Aphis gossypii) weaken the plant, cause leaf curling, and can spread viruses.
Prevention: Spray plants with water to remove aphids. Use neem oil or insecticidal soap. Encourage natural predators, like ladybugs or lacewings.
Rodents
Mice, voles, and rats are attracted to the starchy sweet potato tubers. They dig into the soil to feed on the tubers, sometimes causing severe crop loss.
Prevention: Use physical barriers, such as fencing or mesh, around the garden. Set traps or use natural predators, like cats or barn owls. Keep the garden clean and free of debris where rodents may hide.
Common Diseases
Fusarium Wilt (Fusarium oxysporum):
A fungal disease that affects the plant’s vascular system. Symptoms: Yellowing of leaves, stunted growth, and wilting.
Prevention: Rotate crops. Use resistant varieties. Avoid overwatering and improve soil drainage.
Black Rot (Ceratocystis fimbriata):
A fungal disease that affects tubers, often starting at cuts or wounds. Symptoms: Black, sunken spots on tubers, which may expand over time.
Prevention: Use certified disease-free slips. Practice good field hygiene, rotating crops, and removing infected plants. Handle tubers carefully to avoid wounds.
Scurf (Monilochaetes infuscans):
A fungal disease that primarily affects the skin of sweet potato tubers. Brown, scaly spots on the tuber’s surface, reducing market quality, but not affecting the flesh.
Prevention: Rotate crops regularly. Use certified disease-free slips and avoid planting in infected soils.
Root-Knot Nematodes (Meloidogyne spp.):
Microscopic roundworms that live in the soil and infect plant roots. Galls or knots on the roots, leading to poor tuber development and stunted growth.
Prevention: Use resistant varieties. Rotate crops to non-host plants like corn or beans. Practice solarization to sterilize the soil.
Alternaria Leaf Spot (Alternaria spp.):
A fungal disease that affects the leaves of sweet potatoes. Small, dark spots on leaves that grow larger, eventually leading to leaf drop.
Prevention: Improve airflow between plants by proper spacing. Use fungicides if necessary.
Bacterial Soft Rot (Erwinia spp.):
A bacterial infection that causes the sweet potato tubers to rot, especially during storage. Soft, mushy, foul-smelling tubers.
Prevention: Cure sweet potatoes properly before storage. Avoid damaging the tubers during harvest.
Plant sweet potatoes with other crops that deter pests, such as marigolds, which repel nematodes and other harmful insects.
Companion plants
Companion planting sweet potatoes with nitrogen-fixing plants like beans and pest-repelling plants like marigolds and thyme can greatly benefit your crop. Avoid planting sweet potatoes near heavy feeders like tomatoes and squash to reduce competition and disease risks.
Bush Beans & Pole Beans
Beans are nitrogen-fixing plants, meaning they add nitrogen to the soil, improving fertility for sweet potatoes, which are heavy feeders. Increased soil nitrogen levels benefit sweet potato growth and development without the need for synthetic fertilizers.
Avoid planting beans too close to the spreading vines, so the beans can still get sufficient light.
Radishes
Radishes help deter pests like flea beetles, which can damage sweet potato leaves. Radishes grow quickly and can serve as a trap crop, luring pests away from sweet potatoes. You can plant radishes near the edges of the sweet potato bed or among the vines.
Marigolds
Marigolds have natural compounds that repel nematodes, particularly root-knot nematodes, which can damage sweet potato tubers. Reduced nematode populations help protect sweet potatoes from root damage. Plant marigolds around the perimeter of your sweet potato patch or intermixed to act as a barrier.
Thyme
Thyme’s strong scent helps deter harmful insects, such as cabbage loopers, which can attack the leaves of sweet potatoes. It acts as a natural pest repellent while enhancing the garden’s biodiversity.
Spinach & Lettuce
These shallow-rooted leafy greens grow well in the early season before sweet potato vines take over. They do not compete with the sweet potatoes for nutrients and benefit from the shading effect of the sweet potato vines as they spread. Maximizes garden space early in the season and provides an early harvest. Harvest them before the vines spread too much.
Corn
Corn can act as a natural trellis for climbing beans or vine crops, helping manage the sprawling nature of sweet potatoes. The tall stalks of corn provide shade and help reduce the impact of harsh sun, especially in hot climates. Ensure proper spacing between corn and sweet potatoes to prevent competition for water and nutrients.
Corn is another must-have crop in any survival garden. After all, it’s super easy to grow!
Oregano
Oregano is a ground cover herb with strong oils that repel pests like aphids, beetles, and ants.
Beets
Beets have deep roots that don’t compete with the sweet potato vines, which tend to have shallower root systems. Beets provide an additional crop without competing for the same nutrients or space. Make sure they get enough sunlight before the sweet potato vines start to shade them.
Tansy
Tansy has a strong odor that repels flying insects like whiteflies and ants. Plant tansy near, but not directly next to sweet potatoes, as it can be invasive.
Nasturtiums
Nasturtiums are excellent for attracting beneficial insects such as predatory insects that prey on pests (e.g., aphids), and they can also act as a trap crop for aphids and other pests. They protects sweet potatoes from aphid infestations and brings in beneficial pollinators. Plant them around the perimeter of the sweet potato bed to act as a decoy for pests.
Dill
Dill attracts beneficial insects like ladybugs, lacewings, and parasitic wasps that feed on harmful pests, such as aphids and caterpillars.
Plants to Avoid with Sweet Potatoes
Both squash and sweet potatoes are heavy feeders, meaning they will compete for nutrients and space, potentially reducing yields. All squash varieties, especially winter squash are easy crops to grow and it’s key for your self-sufficient or survival garden.
Also, tomatoes and sweet potatoes are susceptible to similar diseases, such as root rot and blight, so planting them together increases the risk of cross-contamination.
Sunflowers exude allelopathic chemicals that inhibit the growth of nearby plants, including sweet potatoes.
Can I Grow them in Containers?
Yes, you can grow sweet potatoes in containers! It’s a great option if you have limited space or poor soil quality. With the right container, soil mix, and care, you can produce a good harvest of sweet potatoes. Here’s how to do it:
Choosing the Right Container
Sweet potatoes need room to spread their roots and develop tubers, so choose a large container. A minimum of 20 gallons is ideal, though larger containers (e.g., 25-30 gallons) are even better for bigger yields.
The container should be at least 12-18 inches deep to provide ample room for the tubers to grow.
Ensure the container has drainage holes at the bottom to prevent waterlogging, which can lead to rot.
Soil Mix for Containers
Use a loamy or sandy soil mix to ensure good drainage. A good mix would include equal parts of potting soil, compost, and sand or perlite to keep it loose and well-draining. Add plenty of organic matter like compost or well-rotted manure to enrich the soil and help retain moisture while still being light.
Planting Slips
Plant each slip 12 inches apart in the container. In a large container, you may be able to fit 2–3 slips depending on its size. Plant the slips so that the bottom few leaves are just above the soil line and the stem is buried about 4–6 inches deep.
Watering
Sweet potatoes in containers may need watering more often than those in the ground since container soil dries out faster.
Water regularly to keep the soil evenly moist, especially during the establishment phase and hot weather. Water whenever the top 1–2 inches of soil feels dry.
Managing Vines
In containers, you can let the vines trail over the edges, or if space is tight, you can direct them vertically by using a trellis. Pruning is usually not necessary unless the vines are taking over other plants or space. You can gently trim back excessive growth if needed.
Harvesting from Containers
Gently tip the container over or carefully dig out the tubers by hand to avoid damaging them.
Container-Friendly Varieties
Some sweet potato varieties are more suited to container growing due to their compact or bushy growth habits:
- ‘Beauregard’: A popular and productive variety with good-sized tubers.
- ‘Bush Porto Rico’: A more compact variety, making it ideal for container gardening.
- ‘Vardaman’: A bush variety that doesn’t produce long vines, perfect for smaller spaces.
- ‘Georgia Jet’: Known for fast-growing tubers and adaptability to containers.