Description
Sweet potatoes are distinct from regular potatoes and yams. They belong to the Convolvulaceae family, which includes morning glories. The sweet potato's starchy tuberous roots are used as a root vegetable and have a sweet taste.
Sweet potatoes come in a variety of types with different shapes, colors, and textures. They can be white, cream, yellow, reddish-purple, or deep purple. The most significant part of the sweet potato plant is the tuber, a large root that grows underground and is used as a food source. The leaves of the sweet potato plant vary in appearance, some being divided like fingers while others are whole. These leaves are edible and can be cooked like spinach. The plant also produces trumpet-shaped flowers in a range of purple and white hues.
However, it is crucial to be aware that the green fruits that develop from the flowers of sweet potato plants are toxic and not edible.
Planting requirements
Planting season: Year around cultivation is possible. However, the recommended seasons are April to August and September to March
Planting conditions:
| Propagation | Plant cuttings |
|---|---|
| Planting method | Plant within 4 days of cutting. Small slips that sprout directly from a sweet potato can also be planted. Fresh sweet potato seeds also germinate relatively easily but are harder to find. |
| Soil | Sandy/ loam soil with good drainage is suitable. If soil is clay, rocky, or compacted, it is recommended to consider growing plants in raised beds. Focus on developing fertile, well-draining soil for optimal root growth. |
| Water | Keep soil evenly moist. At the crop's initial growth stage water supply is important |
| Light | Requires full sunlight for optimal growth. Plant in an area that receives abundant sunlight. Under shaded conditions, both leaf and root production decrease, and the plant tends to climb to seek sunlight. This results in larger but fewer leaves and fewer tubers are produced in shady conditions. Heavy shade is not tolerated well by the plant, although some varieties may tolerate mild shade. |
Growing conditions:
| Temperatures | This plant grows well with temperatures between 21-26°C |
|---|---|
| Soil | Maintain soil pH level between 5.2 to 6.8 |
| Water | Excess water reduces tuber production. The equivalent of one inch of water weekly is sufficient. Apply to roots. |
| Pruning | Prune plants regularly to maintain their desired size and shape. When plants are pinched or trimmed, it promotes new growth. Remove flower buds to prioritize tuber growth |
| Weed control | It is important to remove weeds at an early stage of the crop, to reduce plant competition |
Harvesting
The time to maturity ranges from 4 to 12 months depending on the variety planted and the altitude at which it is being grown. Discard any tubers damaged by insects, pests, or disease.
- Handle sweet potatoes with care to prevent bruising or breaking their delicate skin.
- Use a garden fork to lift the soil outside the root area and avoid damaging the tender roots.
- Place harvested sweet potatoes carefully into a carrying container, instead of tossing them. Use either hands or a garden fork to harvest sweet potatoes from the ground.
- Avoid washing freshly dug sweet potato roots and handle them minimally.
Curing
Cure the sweet potatoes by leaving them in a shaded area with high humidity for 7 to 14 days.
Storage
Store the cured sweet potatoes in well-ventilated crates or boxes in a cool, dark, and dry place with low humidity. Ideal storage temperature is between 50 to 60°F (10 to 15°C).
Optionally, sweet potatoes can be frozen after the curing process by peeling, cutting, and boiling them until fork tender.
Protecting your plants
Pest control
Pest type:
- Sweet Potato Weevil (Cylas formicarius)
Symptoms:
- Sweet potato weevil infestation can cause the vines to turn yellow, but it may not be noticeable until a heavy infestation occurs. The damage caused by these weevils is primarily seen in the tubers, where their larvae create tunnels, resulting in cavities, a spongy texture, and a dark appearance.
Control method:
- It is important to ensure that the slips or cuttings used for planting sweet potatoes are free of weevils.
- Proper sanitation practices, such as removing discarded and unharvested tubers and controlling Ipomoea weeds, are crucial for managing the weevil population.
- Maintaining moist soil through irrigation helps deter weevils and promotes the development of fungal diseases that can impact the weevil population. Cracking soils can allow the weevil access to tubers.
Disease Control
Disease type:
- Leaf scab (Elsinoe batatas) (Fungus)
- Collar rot (Phytophthora) / Root rot (Fungus)
Symptoms:
Leaf scab:
- Young leaves can become infected with fungus.
- The infection spreads along the veins of leaves, leaf stalks, and stems.
- As leaves grow, the fungus may hinder proper vein expansion.
- Affected leaves may twist, curl, or tear.
- On older leaves, small spots can develop between the veins, causing twisting that exposes the undersides.
- In rare cases, the tips of the shoots may also be damaged.
Collar rot:
- When plants are affected by collar rot or root rot, their leaves will start turning yellow, and eventually, the vines will wilt. The roots may also show signs of rotting.
Management:
Leaf scab:
- Avoid Repeated Planting: Minimize planting crops in the same location to reduce the chance of fungus survival in old plant debris.
- Use Healthy Vines: Always select disease-free vines for planting to prevent the spread of the fungus.
- Monitor and Remove Infected Plants: Regularly check for signs of infection and promptly remove any affected plants to limit spread.
- Practice Crop Rotation: Rotate crops to break the life cycle of the fungus and reduce its prevalence in the soil.
Collar rot:
- Remove Infected Plants and Soil: Regularly remove affected plants and the surrounding soil to minimize the spread of the fungus.
- Monitor Crops: Stay vigilant and regularly check sweet potato plants for signs of disease to take prompt action if needed.
- Prevent Wounding During Harvest: Handle plants carefully during harvesting to avoid injuries that can facilitate disease entry.
- Practice Proper Curing: Ensure that sweet potatoes are cured properly to enhance their resistance to diseases.
- Implement Good Sanitation Practices: Maintain cleanliness in the growing area to prevent disease spread and support healthy crops.
