Learn How To Grow Sweet Potatoes And Start Your Own Garden

You might be a garden lover that knows how to grow saffron, broccoli, tomatoes and even more! But we have something new for you! Sweet potatoes are sweet, but sweeter still is the joy of growing them yourself. Growing these starchy root vegetables is often considered a rite of passage in most farming and gardening circles. If you’ve managed to take care of the odd succulent and are ready to put your green thumb to the test, growing your own sweet potatoes is an excellent first step towards starting your own vegetable garden

A bunch of harvested sweet potatoes

Why should one start growing sweet potatoes, you ask? For one, organic potatoes are a nutritious superfood with a host of health benefits. Your body will thank you for incorporating them into your diet, and the gratification of growing your food is just an added plus. Sweet potatoes are also incredibly versatile. The best part about growing potatoes is that it’s easy as 1-2-eat! They don’t require much care, and it’s hard to mess them up if you follow instructions. Keep reading to learn about planting, growing and harvesting potatoes

Sweet potato varieties

Botanically named Ipomoea batatas, this vegetable is commonly known as sweet potato or yam. One would assume that since it looks like a potato and it’s called a potato, the potato would be related to regular potatoes, but they’d be wrong! Sweet potatoes are from a different family of plants and are closer to morning glory flowers than to regular potatoes

Sweet potatoes and yams are also entirely different vegetables! Sweet potatoes come in white, yellow, brown, and purple skin shades and have distinctive orange flesh. Meanwhile, yams have bark-like skin and white flesh.  Popular potato varieties include Beauregard, Patriot, Centennial Bush Porto Rico, and the cultivar Georgia Jet.

When is the right time to plant sweet potatoes? 

Whether you are planting your sweet potato in a pot on your windowsill, or a home garden, timing is an important factor. Sweet potatoes are native to Southern regions. However, new breeds can be grown in Northern areas as well. The key is planting the potato slips in the optimum season and weather conditions. It can make or break your harvest, as planting too early can endanger the food with winter frost. If you plant too late, the potatoes may not have enough time to grow before winter sets in. 

Since sweet potatoes are originally tropical, their plantation is best suited to springtime. The period of warm weather, warm soil and ample sunlight begins in March. Since the arrival of a new season may differ in different regions of the U.K, an easy way to predict the best time to plant your potatoes is according to the winter frost. The slips of sweet potatoes should be planted in soil 3 to 4 weeks after the last winter frost. This is to ensure a last frost or drop in temperature does not delay or kill the saplings of the potatoes

A gardener digging the soil to take out the sweet potatoes

When the temperature at night time rises above 13°C, you should plant your slips. Since it’s colder in the U.K., you can also plant sweet potatoes under cloches or polytunnels to protect them against the chill and allow them to thrive in a warm place. If you’re growing the plant indoors, you can transplant the sweet potato tubers once they’ve established firm roots. You can also train the foliage up a trellis, strings, or canes to support the potato vines

Another consideration for the right time to plant the slip is how you obtain the slip itself. Sweet potatoes do not grow from seeds but sprouts. These can be bought from plant stores or grown at home. The time needed for preserving or growing the slip needs to be coordinated with the planting time. This will ensure the potatoes have sufficient time to grow and provide a successful harvest. You can keep the slips in potting soil till it is time to plant them. The sweet spot for growing sweet potatoes, pun intended, lies in the perfect timing of planting them.

Preparing the planting site 

Once you have your slips prepared and the spring weather is approaching, you can begin preparing the site where the potatoes can be planted. Sweet potatoes require warm soil as well as warm air. You can either wait for the soil to warm up naturally, or speed up the process by adding a thermal black plastic sheet to the garden bed or pot. This will help warm up the soil and create the optimum soil temperature for slips to thrive.

By adding a thermal mulch or plastic layer, you can plant your slips about a week earlier! Just put down the sheet around three weeks before the plantation, and you’re good to go! If you opt to wait until the weather conditions become optimal, the soil should be at least 15°C. The air temperature that is best for planting potatoes is between 15 and 30°C. Since it’s colder in the U.K., you can also plant potatoes in greenhouse borders or under cloches or polytunnels to protect them against the chill. 

Expert hand of farmer checking soil health before growth a seed of vegetable or plant seedling. Gardening technical, Agriculture concept.

Other measures that are essential preparations for the planting site are ample amounts of sunlight. Sweet potatoes require a steady intake of sunlight throughout their growth, so make sure your site has direct access to the full sun. In terms of the soil texture, potatoes do not have specific preferences. However, the soil must be well-drained. Try to avoid muddy and dense soil. Instead, make sure the soil is fertile and light. This will ensure the roots have sufficient air space to grow and reach. Sandy soil is ideal, and if your soil is compacted, clay or rocky, raised beds for the slips are preferred. 

Sweet potatoes require good nutrition, and proper preparation of the soil can help fulfil their dietary needs. The soil should be fertile and adding multi-purpose compost to it before planting is your best bet. Other options can be organic liquid fertiliser, perlite, or coconut coir, but avoid adding animal manure. Finally, make raised mounds about 15 to 20 centimetres above the soil bed, and make sure they have a distance of 1 foot or 30 centimetres between each one.

How to plant sweet potatoes

Once your garden or soil bed is prepared, you can plant your sweet potato slips. To sow the slips, wait for a warm, sunny day when the soil temperature is around or above 15°C. If you’ve used a thermoplastic sheet, cut holes where the mounds are to be placed and sow the slips in place. Cut the leaves stemming from the sides of the slips, so only the top part has leaves, and push the slip in the soil, so it generously covers the roots and stems. 

Depending on how many potatoes you are planning to grow, each slip should be 30 centimetres apart from the next one. 40 centimetres would be even better if your soil bed has the capacity. This is essential as it allows the roots to expand comfortably and yield a well-sized potato. You should also space individual rows about 3 feet apart to give potato vines a comfortable space to grow. You can add liquid fertiliser to the water you will give to the slips, and make sure it is plentiful. 

For the first week and a half, between 7 and 10 days, water the potato slips daily, so the soil is evenly moist. Congratulations! Your potatoes have been planted and will yield a harvest in 3 to 4 months.

How to grow and care for sweet potato plants

Sweet potatoes grow best when the temperature is between 24°C and 35°C during the growing season, so keep an eye on the weather while tending to your plants. Keep the soil well-drained and ensure that it contains sufficient organic matter to support the growth of the potatoes. Sandy soil should be used if you have that available. Keep the soil evenly moist, and practice deep watering during hot, dry spells to maximise yield. Additionally, be careful not to overwater in the weeks before harvest to avoid splitting or cracking the skin of potatoes.

Some sweet potatoes planted in a site

After the two week mark following planting, start weeding the sweet potato bed. Also, be sure to fertilise, but in moderation, or else you’ll end up with more foliage than tubers. Add commercial 5-10-10 (5% Nitrogen, 10% Phosphorus and 10% Potassium) products to the side of the plants 3-4 weeks after transplanting the potato plant to the soil. Keep the pruners away from potato vines. Let them grow as they need to support the vegetable. Also, keep the deep digging tools away from the roots

Tending to sweet potato plants also involves protecting them from pests. Mist the plants frequently to avoid spider mites and mottled leaves. These insects need hot and dry conditions to thrive, so you should ensure a certain level of moisture. Use beneficial insects or sticky traps to eliminate whiteflies that suck sap from potatoes plants and inhibit their growth. Use disease-free slips bought from the grocery store to grow your sweet potatoes. This will reduce the vulnerability of the plant to disease and damage from wireworms. Lastly, rotate the crop each year, planting the new plants in a different location the next year to counter the risk of infection. 

Harvesting sweet potatoes 101 and tips for storage

Harvest sweet potatoes

You can harvest the sweet potatoes three to four months after planting them when they are fully formed and edible. The leaves can be eaten as greens throughout the season. However, you should be careful not to overdo it, as the plant needs a certain amount of leaves to keep growing.

  • When the foliage starts yellowing, around 100 days after planting, you can dig up the potato, which should be close to the soil surface – about 15 cm deep
  • You can use a garden fork to loosen the soil around the potatoes. Work about 40 cm from the centre of the vine and move inwards. 
  • Then, use your hand to dig out the potatoes by gently pulling at the primary crown of the plant. Work slow and be gentle not to damage the vegetable.
  • Shake off any extra dirt on the potatoes when you’ve freed them, and you’re done!

Harvesting sweet potatoes without damaging the crop

Try to complete the harvest before the first frost in the fall so that the harsh weather doesn’t damage the tubers. The sweet potatoes can still be harvested if the leaves die due to the first frost, but time is of the essence to avoid rotting. It’s best not to cut it too close so all your time, effort, and potatoes, do not go to waste. 

Store sweet potatoes

Before you can eat your hard-earned sweet potatoes, you need to cure or harden them in a warm (around 26°C) place that’s out of direct sunlight. This process takes about 10-15 days after harvest. This will allow the potatoes to develop a second skin to cover up any damage or bruising, and more importantly, develop the sweetness that gave the vegetable its name. 

To store the sweet potatoes, wrap each one completely in a newspaper and place them in a wooden box or a similar container. Be sure not to wash the potatoes to prevent rot. You can store them for up to 6 months in a dry, cool (13-16°C), and well-ventilated place. If you want to refrigerate the potatoes, make sure the temperature inside does not fall below (10°C).

Some sweet potatoes being cut in slices with a knife

Growing sweet potatoes can end up being one of the most rewarding things you ever do, so it’s important to do it right. There is no exact way of growing and tending to potatoes, but this guide has outlined what you should or shouldn’t do to become the best sweet potato grower you could be. The instructions and tips aren’t exhaustive, but they cover all the basics you need to know to get started. Now that you’ve gone through this article and hopefully learned a few things, get out there and get growing!

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