How To Plant, Grow and Harvest Sweet Potatoes
Learn how to plant, grow and harvest sweet potatoes in your own home garden with this step-by-step guide that includes easy ways to start your own sweet potato slips. Learning when and how to plant sweet potatoes has a lot to do with how many pounds you’ll have at harvest time. Sweet potatoes are fairly easy to grow providing they have good warm soil and are kept weed free. Growing sweet potatoes is also an important step in growing the food to fill your pantry. Properly cured sweet potatoes can be stored at room temperature and will last up to a year without any special preservation needed.
How We Use Sweet Potatoes
There’s nothing I love more than sweet potato fries alongside a fresh juicy hamburger, especially in the middle of winter. But there are so many other great ways to eat sweet potatoes too. We enjoy them roasted or baked in the oven, in sweet potato casserole on holidays, in chili, and breakfast casseroles and the list goes on.
Growing sweet potatoes is simple and easy, but very different from growing regular potatoes. For regular potatoes, you actually plant a part of the potato in the ground and that’s the seed. But sweet potatoes grow from little sprouts called “slips” that grow on a potato from last years harvest. You can easily grow your own sweet potato slips if you have access to some sweet potatoes, or you can purchase slips from a seed catalog or local nursery.
Why You’ll Like Growing Sweet Potatoes
The number one reason why you’ll like growing sweet potatoes is that you basically plant them and forget about them until harvest. The second reason why you’ll love growing sweet potatoes is that you’ll get a prolific harvest of beautiful sweet potatoes that don’t need to be preserved. Anytime I can grow something like squash or potatoes that can be eaten all winter long without any preservation, I’m all in.
Varieties Of Sweet Potatoes
There are many different varieties of sweet potatoes and all of them have slightly different traits. There are purple sweet potatoes, orange sweet potatoes, and red sweet potatoes. Some sweet potatoes have a more sprawling growth habitat as opposed to growing more like a bush. My favorite variety of sweet potato for growing in my cold climate is the georgia jet. I’ve grown it for many years successfully. I’ve also grown Beauregard successfully as well.
Growing Zone
One of the first things you are going to want to find out is what growing zone you live in so that you know when your climate will be warm enough to plant outside. The USDA has developed a map that shows the different climates across the country. It is based on the weather history over the last century and they have broken the country up into growing zones. The zone you live in will tell you how cold your winters get on average, and when you can expect to see your last frost date in the spring and first frost in the fall.
It is also important to find other people that garden near where you live and talk to them about their experiences. Sometimes there is microclimates within the USDA hardiness zones that can be warmer or colder depending on elevation and many other factors. Over time you will get comfortable with growing a garden in your environment. Keep in mind that the USDA hardiness zones are based on averages, so before I plant anything outdoors that is sensitive to frost, I always check the 10 day weather forecast to make sure it won’t be near freezing temperatures at night.
Average Last Frost Date
To find out your average last frost date, visit https://www.almanac.com/gardening/frostdates and enter your zip code to find out when you can expect to have your last frost in the spring. After this date, you can safely plant out all of your heat loving plants like sweet potatoes and peppers. Keep in mind that the last frost dates are based on averages over many years. Before I plant anything outdoors that is sensitive to frost, I always check the 10 day weather forecast to make sure it won’t be near freezing temperatures at night.
Free Garden Planning App – Seedtime
My favorite tool for determining exactly when to plant seeds indoor and plants out in the garden, is a free garden planning app called Seedtime. It takes all the guesswork out of figuring out when to start planting seeds indoors. Once you know when your average last frost date is in the spring, you can put that information into Seedtime. The app takes into account cool season versus warm season crops and based on your average last frost date, tells you when to start your seeds indoors. It also tells you when to transplant them outside and when to plan on cultivating and harvesting your crops. Seedtime will also tell you when to plant the crops into your garden that prefer to be direct seeded like potatoes, carrots and corn. Click here to start using this free online gardening app today.
Two Ways To Source Sweet Potato Slips
Purchase Plants (Slips) From Local Garden Centers
If you are a beginner gardener, I would strongly suggest that you purchase sweet potato slips from a seed catalog or a local greenhouse. Starting your own slips is fairly simple, but they aren’t that expensive to purchase, and it’s best to learn how to grow them successfully in the garden, and then move into all aspects of starting your own plants. I purchased my plants from seed catalogts for a long time before I had room for my seed starting racks in my basement. And I still purchase them sometimes when I don’t have enough of my own slips. When you order them from a seed catalog, they will ship them to you when all danger of frost is past. They come in a small bundle of bare root plants that you just simply stick right into the ground.
Grow Your Own Sweet Potato Slips Indoors
To start your own sweet potato slips, you’ll need some sweet potatoes on which to grow your slips. Its best to get organic sweet potatoes instead of regular sweet potatoes from the grocery store because they won’t have been treated for anything that keeps them from sprouting. Mine usually start sprouting by January or February, which is the perfect time to start growing your own sweet potato slips. If your potatoes don’t start sprouting automatically, you can take a whole sweet potato, stick a toothpick in each side of the potato and suspend it in a jar of water, so that one end of the potato is sticking down into the water. Set them in a sunny window and in a few days they will start to sprout.
If you have sweet potatoes from last year’s garden that are starting to sprout like I do, you can just cut off the parts of the sweet potato that are sprouting and place them in a tray of water in a sunny window or under lights. Use the rest of the sweet potato to make something yummy for supper. Once the slips start to grow leaves and roots you can plant them in some seed starting trays or containers and they will continue to grow until it’s time to plant them outside. It’s a good idea to get your sweet potato slips started 6-8 weeks before your last frost date, or even earlier. The longer your vines, the more plants you’ll have.
When started early enough, the slips will grow into plants with long robust stems and many leaves. This will be to your advantage, because you can cut up the stems and plant sections of it in the ground and each section will turn into it’s own plant.
Planting Sweet Potatoes In The Garden
Landscape Fabric To Prevent Weeds
Keeping sweet potatoes weed free is really important for them to be able to have full access to the soil nutrients and sunlight without any competition. I prefer to grow my sweet potatoes on landscape fabric (which you will see demonstrated in the video below). It has helped me keep the weeds out of my sweet potatoes without having to spend time weeding on a weekly basis. Sweet potatoes grow long vines that cover the ground, and weeding among the lush vines can be almost impossible without some kind of fabric or mulch underneath.
Warm Soil
Sweet potatoes are a heat loving crop, and grow best when the soil temperature is at least 65 degrees. Growing on black landscape fabric helps to warm up the soil quicker in the springtime even in cold weather. If you grow in a northern climate like I do, you’ll want to prepare your beds and lay your fabric down at least two weeks before time to plant. This will allow your soil to warm up, so your plants will start growing quickly after being planted.
Plant In Beds
I do most of my growing on 30” wide beds, which is what I recommend in my garden planning tutorial. This is a better use of your space than if you are planting in rows. For sweet potatoes, we plant one row down the middle of each bed, with 12” of space between your plants in row. We average of three pounds of sweet potatoes per plant.
I usually grow 150 sweet potato plants to feed my family of seven. I don’t mind having lots of sweet potatoes because they can be used in so many ways.
Planting Your Sweet Potato Slips
Gently place each slip into a hole in the ground that is deep enough to cover the roots and the stem up to the base of the leaves. If you started your own slips and planted them in trays of soil, you will plant them with the soil intact like you would any other plant. For really long vines that grew in your trays of soil, you can cut chunks of the vine with 5 leaves per chunk. Plant three leaves down into the soil, leaving the top two leaves above ground; The leaves in the soil will turn into roots. This is a great way to get a lot of plants from just a few slips.
It’s best to transplant in the evening, or when it’s cloudy to keep the plants from getting sunburned. After planting, water the seedlings well to encourage new root growth.
Watering Sweet Potatoes
I like to water my garden with drip line because it’s an efficient way to water and I can easily control how much water the plants get. If you don’t have a drip line set up, you can also water with a sprinkler, but dripline is my preference.
Weeding Sweet Potatoes
Even when growing in the fabric there will usually be a few weeds that will germinate in the holes of the landscape fabric. I just take a few minutes and pull them out when they’re small, being careful not to pull up any sweet potatoes. I usually only have to do this a couple of times before the sweet potato vines grow large enough to shade out the growth of any new weeds.
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Harvesting Sweet Potatoes
Harvesting sweet potatoes is the fun part! It’s always fun to see what’s been growing under the soil all summer long. This is a great time to get your kids involved with the garden. It’s important to harvest before frost in the fall, but I usually do a test dig about 100 days after I planted the sweet potatoes to see if they’re ready. If the potatoes are nice sized, go ahead and dig them. But if not, I let them grow until closer to frost. If you let them grow too long they can get misshapen with cracks in them, and then they don’t store as well.
Before harvesting all of the sweet potatoes, I pull the vines off the top and put them into the compost pile. Then I pull up the fabric. I use a garden fork and gently dig up the potatoes. We gather the potatoes into buckets or tubs and then prepare to cure them.
Curing Sweet Potatoes
In order for your sweet potatoes to store for up to a year, it’s important to cure them. To cure your sweet potatoes, lay them out in a high humidity high temperature environment for up to two weeks. This will thicken the skin on the potatoes and increase their sugar content so they will store well. It’s best if the environment is 90% humidiy and 90 degrees. That can be hard for me to do living in a northern climate, so I often just lay my potatoes out in the warmest place I can find, and let them cure that way. That’s another reason for harvesting earlier if your potatoes are big enough, because your outdoor temperatures will be warmer.
You can put your potatoes in buckets in a small room like a bathroom with a heater, and some water. This will make a more ideal environment for curing your potatoes.
Storing Sweet Potatoes
Sweet potatoes are easy to store, and they prefer to be stored at room temperature. They can easily be stored in a box under your bed or anywhere in your house and should keep for a year if cured properly. Remember to save a few for starting more slips for next year. You can also pressure can them if you prefer. Just put chunks of sweet potatoes into jars, cover with hot water, and can at 10 lbs pressure for 90 minutes.
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- Landscape fabric, optional
- Propane torch – only if using landscape fabric
- Sweet Potato Slips – can be ordered different places, but I prefer True Leaf Market, Johnny’s Seeds or Berlin Seeds
- Drip Line
FAQ:
Where Can I Purchase Sweet Potato Plants?
You can purchase sweet potato slips from seed catalogs like Johnny’s Seeds, Berlin Seeds or from your local garden center.
Do Sweet Potatoes Grow Better In Pots Or In The Ground?
Sweet potatoes can be grown in pots or in the ground, but typically they grow better in the ground because the soil moisture is more consistent and they have plenty of room for their roots to grow.
Why Do Sweet Potato Plants Produce Flowers?
Sweet potatoes grow some beautiful flowers that look like morning glory flowers. This is because they are part of the morning glory plant family. The flowers don’t mean anything in particular and are not necessary for the sweet potatoes to produce fruit. They are fun to see growing on the vines in the summer.
How Long Does It Take To Grow Sweet Potatoes?
Sweet potatoes take about 100 days to grow from when you plant them in the springtime until they are ready to be harvested in the fall. Of course, that timing can vary a bit depending on the weather and the growing environment, but the average is 100 days.
What Is The Trick To Growing Sweet Potatoes?
Sweet potatoes like to grow in a warm environment and to be kept free from weeds. As long as those two conditions are present, you will grow big beautiful sweet potatoes.
How Often Should I Water Sweet Potato Plants?
When the sweet potato plants are first transplanted into the garden, they should be watered a little bit everyday to help their roots grow and develop. After that you can begin watering them less until they are only getting about 1 inch of water per week. If you can reach your hand down several inches down into the soil and feel moisture, than they probably don’t need water. The less water you give them the more it will encourage their roots to grow in search of water. If it is extremely hot outside and you see your plants looking stressed, then they probably need a little water.
What Fertilizer Is Good For Sweet Potatoes?
My favorite fertilizer for any of the plants in my garden is a liquid fertilizer called BioThrive. I mix it up in a little sprayer and fertilize my garden plants once a week for the first few weeks after transplant.
When Is The Best Month To Plant Sweet Potatoes?
The best month to plant sweet potatoes is whenever there is no longer any danger of frost. That will vary depending on where you live. To find out when to plant your sweet potatoes, use the free gardening app called Seedtime.
How Many Pounds of Sweet Potatoes Do You Get From One Plant?
How many pounds of sweet potatoes you get from one tomato plant varies greatly based on the variety and growing conditions. You can expect to get an average of 2 to 5 pounds per plant.
What Is The Best Spacing For Sweet Potatoes?
Sweet potatoes can be grown as close as 12” apart. I suggest growing them on a 30” wide bed with one row of sweet potatoes down the center of the row.
What Is The Best Way To Water Sweet Potatoes?
The best way to water sweet potatoes is with a drip system, as overhead watering can increase the chance of blight.
Where To Plant Sweet Potatoes In The Garden?
Sweet potatoes prefer to grow in full sun, in a light sandy loam soil with good drainage. They prefer a soil PH of 5.5 to 6.5 but are widely adaptable and will grow almost anywhere.
To learn more about how I test my soil, click here.
Sweet Potato Pests
Deer like to eat sweet potato plants, so it’s important to grow your sweet potatoes in a fenced area to keep the deer away. Grasshoppers sometimes chew on them a little bit, but I find that if I have properly amended soil, that the plants grow fast enough that the pests don’t have a chance to hurt them much.
Best Tomato Companion Plants Are:
- Leafy greens
- Beans
- Thyme
- Basil
- Dill
- Marigolds
- Radishes
- Corn
- Onions
- Garlic
- Beets
Worst Tomato Companion Plants Are:
- Tomatoes
- Cucumbers
- Squash
- Sunflowers
Sweet potatoes are fun, easy and rewarding to grow, and growing a lot of them gives you a greater sense of food security for the coming winter.
I hope you try growing your own sweet potatoes, and let me know in the comments below which varieties you’re growing and any questions you may have.
How To Plant, Grow & Harvest Sweet Potatoes
Equipment
- Landscape Fabric
- Drip Line
Materials
- Sweet potato slips
Instructions
Grow Your Own Sweet Potato Slips Indoors
Take a whole sweet potato, stick a toothpick in each side of the potato and suspend it in a jar of water, so that one end of the potato is sticking down into the water. Set it in a sunny window and in a few days it will start to sprout. Then proceed with this next step:
- If you have sweet potatoes from last year's garden that are starting to sprout like I do, you can just cut off the parts of the sweet potato that are sprouting and place them in a tray of water in a sunny window or under lights. Use the rest of the sweet potato to make something yummy for supper. Once the slips start to grow leaves and roots you can plant them in some seed starting trays or containers of soil and they will continue to grow until it’s time to plant them outside. It's a good idea to get your sweet potato slips started 6-8 weeks before your last frost date, or even earlier. The longer your vines, the more plants you'll have.
- When started early enough, the slips will grow into plants with long robust stems and many leaves. This will be to your advantage, because you can cut up the stems and plant sections of it in the ground and each section will turn into it’s own plant.
Planting Sweet Potatoes In The Garden
- Gently place each slip into a hole in the ground that is deep enough to cover the roots and the stem up to the base of the leaves. If you started your own slips and planted them in trays of soil, you will plant them with the soil intact like you would any other plant. For really long vines that grew in your trays of soil, you can cut chunks of the vine with 5 leaves per chunk. Plant three leaves down into the soil, leaving the top two leaves above ground; The leaves in the soil will turn into roots. This is a great way to get a lot of plants from just a few slips.
Watering And Weed
- Give your plants about 1 inch of water per week, and pull any weeds that come up through the holes in the landscape fabric. Otherwise, just leave them be until fall.
Harvesting Sweet Potatoes
- It’s important to harvest before frost in the fall, but I usually do a test dig about 100 days after I planted the sweet potatoes to see if they’re ready. If the potatoes are nice sized, go ahead and dig them. But if not, I let them grow until closer to frost. If you let them grow too long they can get misshapen with cracks in them, and then they don’t store as well.
- Before harvesting all of the sweet potatoes, I pull the vines off the top and put them into the compost pile. Then I pull up the fabric. I use a garden fork and gently dig up the potatoes. We gather the potatoes into buckets or tubs and then prepare to cure them.
Curing Sweet Potatoes
- In order for your sweet potatoes to store for up to a year, it’s important to cure them. To cure your sweet potatoes, lay them out in a high humidity high temperature environment for up to two weeks. This will thicken the skin on the potatoes and increase their sugar content so they will store well. It’s best if the environment is 90% humidiy and 90 degrees. That can be hard for me to do living in a northern climate, so I often just lay my potatoes out in the warmest place I can find, and let them cure that way. That’s another reason for harvesting earlier if your potatoes are big enough, because your outdoor temperatures will be warmer.
- You can put your potatoes in buckets in a small room like a bathroom with a heater, and some water. This will make a more ideal environment for curing your potatoes.
Storing Sweet Potatoes
- Sweet potatoes are easy to store, and they prefer to be stored at room temperature. They can easily be stored in a box under your bed or anywhere in your house and should keep for a year if cured properly. Remember to save a few for starting more slips for next year. You can also pressure can them if you prefer. Just put chunks of sweet potatoes into jars, cover with hot water, and can at 10 lbs pressure for 90 minutes.
Video
