Growing purple sweet potatoes is super easy and anyone can do it. You can even grow them in containers! Purple sweet potatoes are healthy and filling and they store very well. In this post, we’ll go over everything that you need to know in order to grow purple sweet potatoes.
Purple sweet potatoes are a bit different than the common orange sweet potatoes that we know so well.
They have a different texture (heavier and creamier) and they are not as sweet as the orange potatoes. They are super healthy for us (more details on that later) and they are just as easy to grow as orange sweet potatoes.
I got my first purple sweet potatoes at a farmer’s market years ago. I was walking around and noticed a vegetable that I hadn’t seen before. I got curious and bought a few of them.
I didn’t mean to grow them, I simply wanted to taste them. I tried to sprout a regular orange potato that year to produce slips that I could plant in the garden but it didn’t work… My potato grew many roots but not one slip.
Purple sweet potatoes are one of the most beautiful and flavorful varieties of sweet potatoes you can grow. Their deep purple flesh is packed with antioxidants and has a rich creamy texture when cooked. Though most popular in warmer climates gardeners across a wide range of zones can have success growing purple sweet potatoes with the right care.
What Growing Zones are Best for Purple Sweet Potatoes?
Purple sweet potatoes thrive in hot humid environments similar to their orange-fleshed cousins. While not cold hardy they can adapt to a variety of climates when properly cared for
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Zones 8-11 – These warm zones are ideal for purple sweet potatoes. Plant slips after the last spring frost when soil temperatures reach 65°F.
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Zones 6-7 – Purple sweet potatoes can grow well here, but may need season extending strategies like black plastic mulch to boost heat and soil temps. Wait until late spring to plant.
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Zones 5 and cooler – Challenging but possible! Choose early maturing varieties and use season extending methods. Start plants indoors up to 8 weeks before your last expected spring frost to get plants off to an early start.
Growing Tips for Cooler Zones
Don’t let a shorter growing season stop you from trying purple sweet potatoes! Here are some tips to help you succeed in cooler climates:
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Start slips indoors in late winter or early spring and transplant after hardening off. This gives plants a head start on the season.
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Use black plastic mulch over planting rows to warm the soil, accelerate growth, and reduce weeds.
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Cover young plants with fabric row covers at night if temps may dip below 50°F.
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Provide wind protection for vulnerable young plants.
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Irrigate regularly as plants dislike drought stress in cool conditions.
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Choose early maturing purple sweet potato varieties best suited to your zone’s season length.
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Gradually hill soil over the developing tubers to insulate them and boost temperatures.
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Harvest potatoes 1-2 weeks before your average first fall frost date.
Growing Purple Sweet Potatoes in Warm Zones
Gardeners in zones 8-11 can easily achieve bumper crops of homegrown purple sweet potatoes. Follow these reliable tips:
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Plant slips 1-2 weeks after your last spring frost when soil temperatures reach at least 65°F.
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Space slips 12-15 inches apart in rows spaced 3-4 feet apart. Give those vines room to roam!
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Prepare soil by mixing in several inches of compost to improve drainage and nutrition. Avoid heavy clay.
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Water young plants regularly until well established. Mature plants are quite drought tolerant.
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Feed plants every 2-4 weeks during the growing season with a balanced liquid fertilizer.
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Remove any flowers on vines to encourage optimal tuber growth rather than seeds.
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Carefully dig up potatoes around 90-120 days after planting your slips, before heavy frosts arrive.
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Cure harvested potatoes for 1-2 weeks in warm, humid conditions before storing long term.
What Growing Conditions do Purple Sweet Potatoes Need?
To achieve the highest yields of stunning purple sweet potatoes, aim for these ideal growing conditions:
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Soil Temperature – Minimum 65°F for vigorous growth and tuber development. Warmer is better.
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Soil pH – Slightly acidic conditions between 5.6 and 6.2 are preferred.
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Sunlight – Full sun for at least 8 hours per day is essential.
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Soil – Loose, sandy loam soil enriched with compost for drainage and nutrients.
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Water – Consistent moisture around 1″ per week. Avoid overly saturated soils.
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Humidity – Thrives in humidity above 60%.
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Air Temperature – Daytime highs of 75-85°F, nighttime lows above 60°F.
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Fertilizer – Moderate feeding with a balanced fertilizer every 2-4 weeks.
Challenges Growing Purple Sweet Potatoes
While generally easygoing plants, a few potential issues can impact purple sweet potato yields:
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Insufficient heat leading to stunted growth and low productivity.
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Overly wet soil causing tubers to rot. Improve drainage.
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Drought stress inhibiting vine and root development. Irrigate when dry.
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Heavy clay soil preventing proper tuber formation. Lighten and amend soil.
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Nutrient deficiencies causing poor vine growth. Fertilize regularly.
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Pests like wireworms, grubs, weevils can damage developing tubers.
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Diseases like stem rot, pox and leaf spot. Practice crop rotation.
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Chilling injury to young plants from cold temps or frost. Use row covers.
Catch issues early and take corrective care to keep your crop thriving!
The Joys of Growing Your Own Purple Sweet Potatoes
With the right variety selection for your zone and attentive care during the growing season, you can succeed at raising a bountiful harvest of antioxidant-rich purple sweet potatoes! Their gorgeous color and creamy sweet flavor make them a treat well worth the space they take up in your garden.
Where to Buy Purple Sweet Potatoes…
Now, that’s the main reason to grow them yourself! It’s hard to find purple sweet potatoes in stores. The first ones I got were from a local farmer but I’ve never seen them in stores and I’ve actually never seen them in the farmers market again…
You might be able to find them in Chinese markets but even in our only Chinese market in the closest city I couldn’t find them.
Online, I found two places…
Friedas sells the Stokes variety by the crate. I just bought the organic crate and I am hoping to sprout them (I received beautiful and firm potatoes in a very reasonable time and I don’t think that I paid for shipping so I definitely recommend this company). Once I do that I should be able to keep a few potatoes from my harvest every year and sprout them in the spring for the garden.
Veggie Farm is based in Hawaii and sells the Okinawan Purple Sweet Potatoes. I have never ordered from them before.
I also found these on Amazon but I am not sure how good they are and if they will sprout. The reviews vary. If you buy them just for eating they might be fine, but if you want to attempt to sprout the potatoes so you can grow your own, I think it would be better to buy directly from the farmer and make sure that your potatoes were not sprayed with anti-sprouting chemicals.
So let’s say that you managed to purchase a few purple sweet potatoes… Let’s learn how to grow purple sweet potatoes…
What is a Purple Sweet Potato?
A purple sweet potato has the same shape (more or less) as the orange sweet potato but its flesh is purple. It’s a little less sweet, it’s dense, healthy, and creamy. Some purple sweet potatoes are purple on the outside as well but not all.
There are three main varieties of purple sweet potato…
Okinawan Purple Sweet Potato – has a whitish skin and purple flesh. It is believed to have come to the Philippines and China area from South America around 1490. The plant reached Japan around 1600 and was initially planted in the island of Okinawa before farmers all over Japan started growing the crop.
Somehow, this potato ended up in Hawaii and became an important part of Hawaiian culture. This is where it is cultivated today for the American market and therefore it’s known today as Hawaiian Purple Sweet Potato.
Molokai Purple Sweet Potato – these are purple on the outside and purple on the inside and were developed on the island of Hawaii. I’ve never tried them but it sounds like they are very similar in shape and taste to the Stokes potato.
Stokes Purple Sweet Potato – this variety has purple skin and a deep purple flesh (the ones in the photo above). They are dense, a little dry, very very healthy, and a little less sweet than the orange potato we know.
They are an American made potato, originated in Stoke County, NC, but are now grown mainly in central California. As far as I understand, a mysterious woman gave a farmer from NC some potato slips many years ago. He planted them and ended up with purple sweet potatoes.
He liked them so much that he kept growing them and eventually they were registered under the name Stokes potatoes. These are the ones that I am growing.
Ube – it’s important to mention this vegetable here. It looks kind of like the purple sweet potato, it’s flesh is purple but the skin is a bit more on the brown side, and many people mistake it for a purple sweet potato, but the ube is actually a yam and not a potato.
It is a staple in the Phillipino and Asian kitchen and you might be able to replace it for a purple sweet potato in recipes that call for ube, but it’s important that you know that it’s not the same thing.
Why You Should Grow Purple Sweet Potatoes | Planting Sweet Potatoes in Raised Beds
FAQ
Where do purple sweet potatoes grow best?
Purple Sweet potato vines need 6 to 8 hours of full sun a day. They can grow well in well draining garden soil, which will allow the tubers to dry out little before they need to be watered again. Growing purple sweet potato vines are different than growing purple sweet potato for the tubers.
Can I grow sweet potatoes in zone 5?
Sweet potatoes need warm soil that is not too fertile
Sweet potato plants are sensitive to chilling and should be planted only after the soil temperature is above 65°F. Here in Zone 5, I aim to transplant around June 10 and harvest in early October.
Is purple sweet potato vine a perennial or annual?
Grown for its showy, exotic-looking foliage, this fast-growing heat lover comes in various colors and forms. Sweet potato vine is easy to maintain and tolerant of different growing conditions, including heat, humidity and shade. It is a tender perennial grown as an annual in most regions.
How long does it take to grow purple sweet potatoes?
Of note, the plant requires a long and hot growing season – it may take from 120-180 days from planting to harvest.