Growing

How to Grow Sweet Potatoes: Complete Guide

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If you enjoy eating sweet potatoes, then we have a complete guide to show you how to grow them in your garden.

These tubers are popular in low-carb diets due to them having fewer carbohydrates than traditional white potatoes.

Sweet potatoes prefer a moderate to warm climate, but some varieties grow in colder weather conditions as well. The southern states offer growing conditions that are ideal for producing the highest yields. These tubers require at least four months of warm temperatures before they reach maturity.

It’s possible to achieve a plentiful harvest from a few plants, provided that growing conditions are optimal.

Sweet potatoes come in bush and vining varieties, with each producing bountiful harvests. Sweet potatoes are the ideal root vegetable for amateur gardeners, as they are resistant to drought, disease and the crop accumulates few pests.

Recommended Sweet Potato Varieties

Some of our favorite varieties of sweet potatoes include:

  • “The Centennial” – carrot-colored, producing high yields, with an excellent storage life.
  • “Beauregard” – This variety has purple skin and orange flesh. It hails from Louisiana but grows well in northern regions as well.
  • “The Jewel” – This copper-colored variety has excellent disease resistance.
  • “Bunch Porto Rico” – This smaller copper-colored variety is suitable for gardeners with limited growing space.
  • “Stokes” – A purple-skinned variety with a high nutrient count.
  • “Vardaman” – Another smaller variety that produces sweets with gold-colored skin and orange flesh.

Planting Your Sweet Potato Crop

If you’re planting your crop in a warm climate, then start your slips around a month after the last frosts hit the ground. By this time, the air will warm up and the ground thaws.

Most gardeners grow sweet potatoes using slips. Slips are the roots growing from the tuber, and gardeners slice them off of their sweet potato and then propagate roots from the slip.

You can get your slips from your last harvest, or buy them from a nursery or garden center if this is your first growing season. To create slips by yourself, visit a grocery store when the new crop hits store shelves in November.

Sweet Potato Slips
Sweet Potato Slips

Choose sweet potatoes that are unblemished and don’t have any cracks. Leave your sweet potatoes in a dry, well-lit area, and they will start to produce slips. One sweet potato should produce around 12-slips, slice them off, and store them in a well-lit, dry area of your kitchen.

Growing in Containers

If you want to grow sweet potatoes in containers, then we recommend that you use a 1.5-gallon pot for two slips. Material pots offer the best growing conditions for your slips.

These pots allow air to enter through the sidewalls of the container, increasing growth while providing excellent soil drainage.

  • Fill your pot with potting soil and add some mulch as well.
  • Plant the slips at a 45-degree angle to let the sprouts grow toward the soil’s surface. After the sprouts reach 12-inches in height, you can transplant them into the garden.
Sweet Potatoes in Pots
Growing Sweet Potatoes in Pots

Growing in the Garden

When the last frosts finish, prepare your soil, and plant your slips about an inch below the surface. Water to start the growth process, and leave your slips for 90-days to until you see the first sprouts emerge.

  • Prepare your growing area by tilling the soil to a depth of 10-inches. Build mounds of soil around 6 to 8-inches high, and about 12-inches in width.
  • It’s vital that you use fertile soil with plenty of nutrients to help your sweet potatoes attain maximum size during the growing season.
  • Drainage is also important to ensure that your potatoes don’t get waterlogged and rot.
  • Plant your slips 12 to 18-inches apart, and deep enough to submerge the roots along with a ½-inch of the stem.
  • Water your slips with a liquid fertilizer high in phosphorous, then water once a day for the next 4-days to ensure that the sweet potato slips root properly.
Planting Sweet Potatoes
Planting Sweet Potatoes

Growing Sweet Potatoes

We recommend that you side-dress your sweet potatoes three to four weeks after transplanting. By this stage, the plants will have a root system strong enough to deal with rapid growth. Use around three pounds of fertilizer per 100-feet of planting row. The ideal nutrient balance for your fertilizer should feature a 5-10-10 mixture of prosperous, nitrogen, and potassium.

Side dressing is the application of fertilizers in a shallow furrow or band along the side of vegetable row crops or in a circle around individual plants.

If your garden has sandy soil, then you’ll need to increase your fertilizer requirements to five pounds. Sandy soil doesn’t hold on to nutrients the same way a potting soil or other soils with loamy texture. As a result, you need more fertilizer to balance the run-off from your soil.

Till the beds occasionally to aerate the soil, and stop weeds from getting out of control. Weeds will accelerate their growth after you finish fertilizing. Therefore, we recommend that you weed regularly for the first three weeks after fertilizing the soil.

Sweet Potatoes Growing
Sweet Potatoes Growing

You can reshape your growing beds using mulch and soil to build up the soil around the vines and protect the tubers below the surface of the soil. There’s no need for you to prune the vines, as this practice only slows the growth of the plants.

Watering your plants is essential if you want to get them to produce a bountiful harvest in the fall. We recommend that you deep water your sweet potatoes during dry, hot periods of the summer. This watering strategy will increase your yield come harvest time.

Some gardeners may want to keep some of the harvests to produce slips or store in your root cellar. We recommend you avoid heavy watering in the late stage of the season. Over-watering this far into the fall may cause your tubers to crack.

Pests and Diseases Affecting Your Sweet Potato Crop

In most cases, sweet potatoes are reasonably resilient to infection with diseases, and they are resistant to pest infestations as well. However, bugs and pathogens can still get to your sweet potatoes if the growing conditions are not favorable.

The biggest pest threat to your sweet potato crop comes from flea beetles. These insects burrow into the stem, causing wilting of foliage and withering of the plant’s stems.

Fungal disease is more of a problem with your sweet potato crop than pests. Some of the more common types of diseases infecting your crop are sweet potato scurf, white blister, Alternaria leaf spot, and blight. Watch your plants for signs of stem rot throughout the growing season as well.

The fungal disease tends to show up when the weather turns overcast, rainy, and cold. These conditions provide the ideal environment for the spread of pathogens in your crop. Many pathogens will also overwinter in the soil, affecting the following season’s crop.

We recommend you use a crop-rotation technique that allows you to remediate the soil at the end of each growing season.

Harvesting Your Sweet Potatoes

Most sweet potato varieties are ready for harvesting around the early fall in October. It takes the tubers around three to four months to reach maturity, producing potatoes that are large enough for a meal.

Most varieties will produce over a dozen potatoes, and you’ll know it’s time to dig them up when the leaves on the stems start to turn yellow. In most cases, it takes around 100-days for the slips to develop into a harvest that ready to dig out of the garden.

The roots of the sweet potato may spread out up to 4 to 6-inches deep in the soil. You’ll need a garden fork to help you dig them up, especially when the soil is starting to compact toward the ends of the growing season.

Start your harvest by digging up the soil in an 18-inch radius around the stem of the plant. This strategy prevents you from piercing the tubers with the fork when digging. Cut the vines back, and pull up the plant by the crown. Use your garden fork to loosen the soil as you pull.

Shake off any loose dirt after digging up the tubers, and handle the sweets gently as they bruise easily. Make sure you don’t wash the potatoes after harvest, or they may rot during the curing phase.

Harvesting Sweet Potatoes
Finally! Harvesting Your Sweet Potatoes

Storing Your Sweet Potatoes

To give your sweet potatoes that delicious sweet taste, you’ll need to give them time to process the sugars. Therefore, we recommend that you cure your sweet potatoes in a root cellar after harvest.

Sweet Potatoes
Beautiful Sweet Potatoes

After digging up your sweets, and shaking off the loose soil, wrap each of them in newspaper and space them on a table in the shade of a tree in the garden. Avoid stacking your potatoes on top of each other as this may cause bruising and rot in the tubers.

During the curing process, keep your sweet potatoes at a stable temperature of 80F with 90-percent relative humidity. The curing process takes two weeks, and by this time, your sweet potatoes will be ready to cook.

Store your potatoes in the root cellar under cool conditions for up to 6-months. The root cellar should not reach above 60F. Be careful when removing your sweets from storage, as they bruise easily and start to rot is mishandled.

Hollie Carter

Hollie is a life-long gardener, having started helping her Dad work on their yard when she was just 5. Since then she has gone on to develop a passion for growing vegetables & fruit in her garden. She has an affinity with nature and loves to share her knowledge gained over a lifetime with readers online. Hollie has written for a number of publications and is now the resident garden blogger here at GardenBeast. Contact her at hollie@gardenbeast.com or follow on twitter https://twitter.com/greenholliec

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