How to Grow Sweet Potatoes Successfully

Learn how to grow sweet potatoes, and the returns are worthwhile. These tubers are rich in vitamins A and C, and the plants are easily grown in almost any garden. As a rule, anyone will succeed well with them, and I, for one, am so glad that I had a stake in the game, for the sweet potato is a warm-season crop, and the tubers in autumn can be stored for the winter.

You'll love their double duty. Both the delicious tubers can end up on your table, along with the nutritious leaves. The greens are great used in stir-fries, while properly cured tubers will store for 6 to 10 months! A great option for food security.

Like Vardaman for small gardens, those with larger spaces may prefer the vining varieties. I always advise beginning with slips made from organic tubers. The plants are more vigorous. The harvest is satisfactory, and, properly housed, they will last through the winter months.

Using Sweet Potato Greens

Sweet potato greens are highly nutritious. They boast 302μg of vitamin K per 100g. Spinach weighs in at 483μg. I always harvest young leaves for salads, as they are tastier and sweeter than the older, earthier leaves. Take no more than one-fifth of the leaves each week, and your plants won't yield.

Harvest early in the day, before the moisture from dew has evaporated, and when the leaves are still crisp. Cut with scissors for a clean cut stem. I like the top tender shoots. They are delicious sautéed in olive oil with garlic. Wrap the greens in damp paper towels and store them in the refrigerator; they will keep for up to five days in your crisper bin.

These greens are often used as a thickener for broth-based soup. They can also be pureed into smoothies. The leaves of these greens provide nutrition but minimal flavour. These greens also need to be washed thoroughly before cooking, and their stems should be removed as they can be difficult to eat.

Once you have harvested crops, they will tend to regenerate and grow bushier. Harvesting plants by regular picking reveals new growth. Avoid picking leaves from a plant that has been stressed by drought. Stressed and damaged plants tend to take longer to recover. Enjoy this opportunity to grow more crops above ground while the underground tubers are developing.

Pest and Disease Management

Let's begin with organic prevention to protect your sweet potatoes. Solarize your soil before planting by covering it with clear plastic for six weeks. This should kill off many pests. Use ladybugs to control aphids; I've seen both methods greatly reduce infestations without the need for pesticides.

Although the Japanese beetles chew holes in leaves, they won't affect your tubers. Handpick them in the early morning while they are sluggish, and keep traps set away from the plants. Damaged leaves mean you'll have less photosynthesis taking place. I like to check over my plants weekly at the height of the beetle season. If you wait too long, you'll experience significant defoliation.

Spray beneficial nematodes to control grubs in the soil. These microscopic worms will attack the larvae of the grubs. Mix with water and drench bare ground and soft soil around trees. I apply them at planting time and then again in midseason. They work best when the soil is moist, and the ground temperature is above 60 degrees. Reapply after a heavy rain.

Choose disease-resistant varieties. Beauregard has wilt resistance and also resists other soil diseases. Be sure to rotate your crops at least every three years. Do not plant where the tomatoes or peppers were harvested last year. I've saved entire harvests by simply growing the right varieties up front.

Choosing the Right Variety

Choose between bush and vining varieties based on the available space. If you're searching for a compact bush type for a small garden, look for one like Vardaman that will only spread 3 to 4 feet. Vining varieties need 8 feet to climb and spread. I'd recommend Bush types for container growing, and vines for larger plots.

Consider your maturity times carefully.The shorter-season varieties, such as Georgia Jet, will mature in around ninety days and are well-suited to the northern zone. The long-season types, such as those from Puerto Rico, require 110 days or more and are suitable only for the consistently southern regions.

Storage capacity varies depending on the type of flesh. Moist-flesh varieties, such as the Covington, will store for 6 to 10 months if properly cured. Dry-flesh types, such as Bonita, typically last only 4 to 6 months. I prefer using moist types for winter storage because they become sweeter over time.

Selecting climate-adapted varieties is essential. The heat-tolerant cultivar Beauregard has great success in southern summer conditions, while the cool-weather cultivar Bonita thrives in cooler climates with shorter growing seasons. Before deciding which variety to grow, always check with your local extension office for specific planting guidelines tailored to your area. Test the product locally before you purchase.

Starting and Planting Sweet Potatoes

Start slips using soil or water methods. Soil propagation is more reliable in my experience. Bury whole tubers in a seed mix, but be aware that you won't see a sprout for three to four weeks; you can expect a 90 percent success rate. For the water method, suspend tubers in a jar of water; it takes a little longer, and your success rate will be lower.

Maintain a soil temperature of 75°F (24 °C) for optimal sprouting. I set my trays right on seedling heat mats. Grow lights help prevent leggy sprouts from reaching for the light. Sprouting occurs much more slowly in cooler soils. Check your temperatures daily with a probe thermometer. This is important for healthy slips.

Plant out slips at half their length, covering the stem completely, but leaving the leaves exposed. Or, if preferred, plant out with the leaves also covered up a little way. Taking care to firm the soil well to prevent air from surrounding the roots, I make the holes with a trowel. For best results, plant the plants from 12 to 18 inches apart, on raised ridges.

Water daily for the first critical week. This helps establish root systems quickly. Use a gentle spray of water to avoid disturbing the soil too much. You will find me checking soil moisture each morning. After the seven days, reduce watering to deeper, less frequent intervals.

Caring for Growing Plants

Train vining varieties up pathways on soft plant ties. Guide the vines while the stems are still pliable. Bushes need to be pruned back to remove overcrowded stems. I use tomato cages to hold up the vines where they are exposed to wind. Don't bend the vines at sharp angles, or they will crack.

Feed plants with potassium-rich fertilizers when the tubers are forming. Use wood ash as a quick source of potassium, at a rate of 0.5 pounds per square yard. Kelp meal is slow-acting, and I mix it up each month into the surface soil. Don't use a high nitrogen fertilizer, or you'll get lots of green leaves, but virtually no roots.

Apply mulch, preferably organic, once the soil has warmed adequately. Straw is fantastic in hot climates. Keeps soil temperatures stabilized. Black plastic warms the soil in cooler areas. Maintain a depth of 4 to 6 inches. I renew mine mid-season when it begins to break down. This prevents weed competition.

Look for signs of water stress, such as leaf curl. This is a sign that the plant needs watering right away, as well as slow growth during hot periods. In the summer, I check the plants at breakfast time and again in the evening to see if watering is required. Deep watering once a week is infinitely better than light sprinklings every day.

Harvesting, Curing, and Storing

Harvest the sweet potatoes when the leaves begin to turn yellow, about 90 to 120 days from setting the plants, when the tubers will be mature; I run my fingers through the soil near the crown of the plants to ascertain the size of the tubers, before digging. Do not wait for frost, as this tends to injure the delicate skin. Cut down the vines two days before harvesting to toughen the skins.

Cure the tubers at 80-85°F with 90% humidity for a period of 10-14 days. I utilize a small room with a space heater and humidifier, and I stack the tubers in a single layer on racks. This step not only heals the wounds sustained during handling but also converts the starches into sugars. Taste them after this, before storing them, to see if you can detect the new sweetness.

Store cured tubers at 55-60°F with ventilation. Wrap each in a sheet of newspaper, and be sure they have space or air holes in the crates. I check the storage area every month for spoilage. The moist-flesh kinds, such as Covington, will keep well for 6 to 10 months. The dry-flesh varieties are best used within 4 to 6 months, such as Bonita. Discard any sprouted tubes immediately!

Never put uncooked sweet potatoes in the fridge; cold air below 50° F does flavor damage to them. Purple types, such as Okinawa, require more humidity, so I try to keep them in a separate area (in individual boxes) and wrap them in damp towels. Sweet potatoes stored properly will provide you with essential nutrition during the winter. Enjoy your sweet home-grown dessert no matter what the weather.

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Conclusion

Choosing the right sweet potato varieties for your climate makes all the difference. Heat-loving Beauregard thrives in southern gardens while cool-tolerant Bonita suits northern zones. I always test new varieties in small patches first. This way, you don't waste valuable garden space for little return.

Practice proactive pest management. Release beneficial nematodes when you plant to eliminate grubs. On cool mornings, you can handpick Japanese beetles from your roses. Rotate your crops annually to prevent diseases from recurring. There have been times I've saved the harvest because I caught the problem early. It is always more beneficial to prevent a problem than to cure one.

Don't forget to cure. Curing, or allowing starchy tubers to sweeten, requires two weeks of moisture at a temperature of 80-85°F. I've tasted the difference curing starchy tubers makes, as it develops a much richer flavor and also causes them to store longer. Properly curing starchy tubers starts with replacing their starchy taste with a sweeter taste. In fact, properly curing also increases their shelf life. The total shelf life increases approximately twice in most starchy tubers after curing.

Store different types of flesh separately (moist types require a 55-60°F refrigerator with ventilation; wrap dry-flesh types in damp towels). Once a month for several months, I check the stored tubers for sprouts and soft spots, and discard the ones that are bad. You will live on the results of your harvest for the entire winter.

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