How Do Sweet Potatoes Grow?

Last Updated on August 26, 2020 by

Sweet potatoes thrive in any average soil that is well-drained and in a sunny location. These crops should be planted when the soil has warmed up since they are tropical in origin. Once you bury the slips, compress the soil down tenderly but consistently and water them well.

Benefits of Sweet Potatoes

Sweet potatoes are beautiful, whether you place them in a garden, a trellis, or even a simple container. The starchy, sweet-tasting tuberous roots have several health benefits that make them a good part of your diet. They are loaded with various minerals, fiber, vitamins, and phytonutrients that boost your body and mind. They can also function as a trailing houseplant or as a temporary groundcover.

You can boil, bake, or use them raw in desserts, soups, casseroles, stir-fries, or bread. You can also try them in sweet potato fries at home.

How to Plant Sweet Potatoes in Your Backyard

Sweet potatoes do well in a sunlit vegetable garden, but they can as well flourish in other outdoor space areas. The warm-weather crops can grow under different conditions, from temperate climates to tropical regions. 

These crops can thrive in poor soil, but they may develop malformed roots in clay or become long and stringy in sandy soil. Follow these steps;

Step 1

Create broad, long 10-inch high ridges that are 3 1/2 –feet apart to achieve a suitable environment. ( Each 10-foot row should produce eight to ten pounds of potatoes.)

Step 2

Use a lot of manure and avoid nitrogen-rich fertilizers that can produce stunted tubes and lush vines. Cover the lifted rows using black plastic to retain the soil’s heat and enhance strong growth.

Step 3

Get slips (plant root sprouts) from mail-order suppliers or nurseries. Sweet potatoes bought from stores are usually waxed to avoid sprouting, so spare a few tubers from your crops to plant in the next season.

Step 4

If you are planting sweet potatoes outdoors in your place, put the roots in a container of moist sand, chopped leaves, and sawdust in a warm area. It would be best if you did this about six weeks before planting time.

After your shoots sprout and reach a length of 6 to 9 inches, cut them from the root. Cut the bottom inch and discard it as this portion may harbor disease-causing organisms. Plant the crops in bright sun about 3 to 4 weeks after the last frost.

Make holes six-inches and twelve-inches apart and cover the slips up to the top leaves, compress the soil gently down but tightly and water them well.

Step 5

Mulch the vines a fortnight after planting if you are not using black plastic. Mulching helps to conserve moisture, smother weeds, and keep the soil loose for roots to develop. Lift the longer vines occasionally to prevent them from forming roots at the joint and also undersized tubers.

Avoid touching the plants as this may cause wounds that make them vulnerable to disease spores.

Step 6

If the weather is dry, give your plants an inch of water once per week until it is two weeks to harvesting. Allow the soils to dry a bit and avoid overwatering, which can cause the plants to rot.

Requirements for sweet potatoes to grow

Sweet potatoes require specific conditions for them to thrive well which include;

  1. Soil

Ensure that you plant your sweet potatoes in well-drained soil with high organic matter content. You can choose sandier ground instead of using dense clay.

2. Light

Sweet potatoes should be planted in full sun to part shade. These crops do well in full sun and appreciate a little afternoon shade in dry, hot regions.

3. Water

Sweet potatoes endure growing in dry soil once they are established. Ensure that you keep the soil consistently moist with one inch of water once every week. You don’t have to water the crops during the last three to four weeks before harvesting to prevent the mature tubers from splitting.

4. Fertilizer

Sweet potatoes do not require fertilizer at the time of planting. But you can fertilize the crops about two weeks after transplant with potassium and phosphate fertilizers. You can also add compost to the beds before transplanting.

5. Humidity and temperature

You should not plant sweet potatoes outdoors until the soil is warm enough. They need a temperature range between 60-85 degrees Fahrenheit and air temperature range between 65-95 degrees.

How to grow sweet potatoes in pots

There are two main types of sweet potatoes i.e., edible roots bred for vegetables and inedible ones produced for their ornamental trailing foliage. The two types are easy to grow in pots and are technically edible, though the ornamental ones are described as ‘barely edible’ as their roots are smaller and less sweet.

Both ornamental and edible sweet potatoes grow well in large pots and sunny conditions. They are available for sale as small container crops in the spring. You can also grow them by sprouting slips from tubers.

Tools and supplies needed

To propagate your sweet potatoes in a pot, you will need;

  1. Sweet potato tubers
  2. Toothpicks
  3. Knife
  4. A shallow dish
  5. Glass container
  6. Planting containers
  7. Good-quality potting soil

Look for sweet potato tubers that are firm, with no bad spot and which have not been refrigerated. Follow the steps below;

  1. Prepare the tubers

If you have large tubers, you will need to cut them into large pieces to place them in water for sprouting.

  • Use a sharp knit to cut the tubers into small pieces, the size of the opening on the jar.
  • Locate the center of each tuber piece and insert about three or more toothpicks into it. Let the toothpicks go into the tuber about 1/2-1inches and space them evenly along the circumference. If the tuber is hardened, use a thin hole to drive the toothpicks.

2. Place the tubers in water.

Position the tubers in water to sprout into slips, which will be used to produce new sweet potato plants. 

  • Place the tuber on top of the glass and let the ends of toothpicks rest on the edge with tuber’s end facing down.
  • Fill a glass or jar with enough water to cover the bottom part of the tuber.
  • Place the container on a windowsill where there is sunlight. Make sure you change the water occasionally and allow the bottom of the tuber to remain submerged in water.
  • Wait until green growth sprouts from the bottom of the tuber.

Avoid tap water as it may contain chlorine and other minerals that prevent the tuber from sprouting. You can use distilled water in place of tap water.

3.  Separate the slips    

After the tubers have sprouted, separate them into slips that can be planted individually.

  • Take each sprout and separate it carefully from the tuber. Twist the slip gently as there may be rudimentary root joined to it.
  • Place every slip into a shallow bowl and let the stem submerge in water and the leaves hang over the edge of the container. Within a few days, new roots will start to grow from the bottom of the slip.       
  • You can plant the slips in potting soil when the roots are about an inch long. Discard any wilting slip or any that has no roots as they are not viable.          

4. Plant the slips in containers

If you are planting your sweet potato vines for decoration, look for a small seedling pot with good drainage. Once the plants thrive indoors, you can transfer them to large containers with other plants. If you want to grow edible tubers for vegetables, you can use a bucket or a large container to give them adequate room to grow.

You can also use the seedlings from the pot to plant the edible sweet potatoes in the ground.

  • Fill up the container with excellent-quality potting soil up to one inch below the rim. Ensure you use loose soil for the tubers to grow large.
  • Fill the bottom of the container with slow-release fertilizer and mix it with the soil.
  • Using a stick, make a hole at the center of the soil and let it be deep enough to cover the roots of the slip. Put one or two slips into the hole gently and pat the soil firmly around them and ensure there are air pockets close to the roots.
  • Water thoroughly and add more soil if it settles.
  • Put your pot indoors in a sunny spot and keep the soil moist and not wet.

Your plants may grow fast, depending on the size of the container. You may need to prune the roots or change the pots if they become root-bound within the container.

5. Moving your sweet potatoes outdoor

Before moving your sweet potatoes outdoor, ensure that the soil is at least 60 degrees Fahrenheit. You can wait for around one month after the last frost date and take time to prepare your planting site to get loose soil.

6. Harvesting

For vegetable varieties, you can harvest at any stage, and they will be edible. Depending on which type you have, sweet potatoes usually take 100-140 days to mature fully. For best edibility, make sure you harvest before the first frost in the fall.

Cure the sweet potatoes in warm water and dry them for ten days to two weeks before eating. Treating them this way will give the best flavor and extend the shelf life.

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