How to Grow Sweet Potatoes in Arizona
Sweet potatoes need a long, warm growing season. They tolerate heat and dry air, and they have few pests or diseases. On paper, that makes them perfect for Arizona’s low desert. They’re supposed to be easy. Then many desert gardeners dig in October and find a huge tangle of vines and almost no sweet potatoes. That happens in my garden sometimes too.
I grow sweet potatoes in raised beds, in the ground, and in containers in Mesa, Arizona. Timing makes the biggest difference here, followed by watering through the summer and how you cure them after harvest. This guide walks through what I do, what has gone wrong, and how to get an actual harvest instead of only vines.
Key Takeaways: Growing Sweet Potatoes in Arizona
- Sweet potatoes thrive in Arizona’s warm climate but require proper timing and care for a successful harvest.
- Start slips indoors from January to April, and plant them outdoors between March and June for best results.
- Ensure well-draining, slightly acidic soil; plant slips deeply and give them space to grow for larger tubers.
- Water deeply, but less frequently, allowing the soil to dry between watering to prevent sogginess.
- Cure harvested sweet potatoes in a warm, humid area for 10-14 days, then store them in a cool, dry place for long-lasting quality.
Article Outline:
- Quick Answers for Growing Sweet Potatoes in Arizona
- When to Plant Sweet Potatoes in Arizona
- Which Sweet Potato Varieties Grow Best in the Low Desert?
- Where to Plant Sweet Potatoes
- How to Plant Sweet Potato Slips
- How Often to Water Sweet Potatoes in Arizona
- Do Sweet Potatoes Need Fertilizer?
- Should You Trim Sweet Potato Vines?
- Why Am I Getting All Vines and No Sweet Potatoes?
- Other Sweet Potato Problems in the Desert Garden
- Can You Eat Sweet Potato Leaves?
- When to Harvest Sweet Potatoes in Arizona
- How to Dig Sweet Potatoes Without Damaging Them
- How to Cure Sweet Potatoes in a Dry Climate
- How to Store Sweet Potatoes When It’s Warm
- Growing Sweet Potatoes FAQs
Quick Answers for Growing Sweet Potatoes in Arizona
- Start slips indoors from January through April.
- Plant slips outside March through June. For a harvest, plant in March or April. May and June plantings work best as a summer cover crop.
- Plant in full sun and give the vines several feet to spread in every direction.
- Water as often as every other day in summer, less often when it cools down. Mulch the soil.
- Leave them in the ground until late October if you can. Dig down and check before you harvest.
- Cure them somewhere warm and humid for about 10 days, then store them somewhere cool, dark, and dry.
When to Plant Sweet Potatoes in Arizona
In the low desert, plant sweet potato slips outside from March through June, once the soil has warmed to about 65°F. You can check soil temperature before planting with an inexpensive soil thermometer instead of guessing. See all the low desert planting dates in my Vegetable, Herb & Fruit Planting Guide.
Start slips indoors from January through April so they’re ready when the soil warms. You can learn how to make sweet potato slips with the fast soil method or the traditional water method in this post.
If you want sweet potatoes to eat, plant in March or April. Slips planted in May and June grow plenty of vines, but they don’t always give you a harvest.
Heat is the reason. Sweet potatoes start forming their storage roots in the first few weeks after planting. Daytime highs above 104°F and nighttime lows above 90°F can hurt storage root formation. Slips planted in March or April get to set roots while days are warm and nights are still mild. Slips planted in May and June are still setting roots when the heat arrives.
I plant sweet potatoes twice a year, for two different reasons:
- Spring planting for a harvest. Slips go in during the spring and stay in the ground until late October.
- May and June planting as a cover crop. I tuck slips into empty spots in the garden in late spring and early summer. These later plantings don’t always give me a harvest, but the vines cover the soil and keep something growing during the hottest months. I pull them out when I’m ready to plant in the fall.
For more summer cover crop options, see these heat-tolerant summer cover crops.
Which Sweet Potato Varieties Grow Best in the Low Desert?
Most sweet potato varieties do well in our long growing season. I’ve grown Beauregard, Stokes Purple, and Murasaki. They grow differently and taste different, so it helps to know what you’re choosing.
| Variety | Skin and flesh | Days to maturity | Texture and flavor |
|---|---|---|---|
| Beauregard | Copper-red skin, orange flesh | About 90 to 100 days | Moist and sweet. The classic orange sweet potato. Get Beauregard slips here. |
| Murasaki | Purple skin, white flesh | About 100 to 120 days | Drier, fluffier, and nutty. Holds its shape when roasted. Stores longer than orange types. |
| Stokes Purple | Purple skin, purple flesh | About 120 days or longer | Dry and dense, less sweet. Cooks best low and slow. |
Purple varieties generally take longer to mature than orange ones. In my garden, that means planting purple varieties early in the spring window matters even more.
Days to maturity on a slip label are written for milder summers. In the low desert, summer heat slows tuber growth, and a lot of the sizing up happens as temperatures cool down in September and October. Treat the number as the earliest you might dig, and plan to leave them in longer.
Dry-fleshed varieties like Murasaki and Stokes Purple won’t turn soft and syrupy the way Beauregard does. That texture is normal for these varieties. They’re great roasted, and the drier flesh helps them last longer in storage.
Where to Plant Sweet Potatoes
I grow sweet potatoes in full sun. They handle our summer sun well, and the more sunlight reaches the leaves, the bigger the sweet potatoes underground. Give them room. My vines spread several feet in every direction, over the edges of the bed and into the paths. Plan for that before you plant them next to anything you need to reach.
Soil
Sweet potatoes need loose, well-draining soil so the roots can expand. Loosen the soil at least 8 to 10 inches deep. Heavy clay or compacted soil leads to long, skinny, twisted roots.
If you’re planting in the ground, mix in plenty of compost first. In raised beds, start with good raised bed soil and top it off with compost. The best soil for raised bed vegetable gardens is loose and full of organic matter, which is what sweet potatoes want.
Go easy on fresh manure and high-nitrogen amendments. Rich, nitrogen-heavy soil grows beautiful vines and fewer sweet potatoes.
Raised beds, in the ground, or containers
All three can work.
- Raised beds give you loose, well-draining soil that warms up quickly in spring.
- In-ground plantings give the vines the most room to roam.
- Containers and grow bags work if you’re short on space. Use one that holds at least 10 gallons so the roots have room to form. Containers dry out much faster in summer, so plan on more frequent watering.
How to Plant Sweet Potato Slips
Sweet potatoes grow from slips, which are rooted shoots that sprout from a mature sweet potato. You can grow your own or buy them.
- Bury each slip up to its top leaves. Roots form along the buried stem.
- Space plants 12 to 18 inches apart.
- Water well after planting.
Keep the soil evenly moist for the first two weeks. Letting the soil get close to dry in the first two weeks after transplanting leads to more pencil roots and misshapen sweet potatoes. Once the plants are growing, they can handle drier soil between waterings. For more information on growing your own sweet potato slips, read this guide.
How Often to Water Sweet Potatoes in Arizona
Once sweet potatoes are established, they tolerate dry conditions better than soggy soil. Too much water causes problems like root cracking.
In summer, I water as often as every other day. In cooler months, I water less often. How I water depends on where they’re growing:
- Raised beds: I water raised beds with a Garden Grid. It waters the whole bed evenly, which matters when vines cover the soil and you can’t see what’s dry. I cover watering raised beds with a Garden Grid in more detail in this post.
- In the ground: drip irrigation.
- Containers: ollas. Containers dry out fast in summer, and an olla keeps moisture steady at the roots. I get my ollas from Growoya.
Mulch the soil. Mulch keeps the soil cooler, slows evaporation, and smooths out the wet-dry swings that lead to cracking. This post explains what I use for mulch in a desert vegetable garden.
For containers in summer, see these tips for watering containers in summer heat.
Do Sweet Potatoes Need Fertilizer?
Sweet potatoes don’t need much. Soil with plenty of compost does most of the work.
I feed lightly with AgroThrive general-purpose fertilizer once the plants are established, usually in July, and I don’t feed again after that. Extra nitrogen pushes vine growth at the expense of the sweet potatoes.
Should You Trim Sweet Potato Vines?
Let the vines grow if you want the largest harvest. The leaves feed the sweet potatoes, so the more leaf area in the sun, the bigger the harvest.
Watch for vines that root into the soil along their length. Each spot where a vine roots can form its own small sweet potatoes, which spreads the plant’s energy across lots of undersized ones. Lift those vines every so often to break the new roots.
If space is tight, you can grow vines up a trellis. I usually let mine tumble over the ground.
Why Am I Getting All Vines and No Sweet Potatoes?
This is the most common sweet potato problem, and it’s frustrating. You water all summer, the vines look amazing, and there’s almost nothing underneath. It happens to me sometimes too.
Several things cause it, and in Arizona they often pile on top of each other.
Heat during root formation
Sweet potatoes decide early how many storage roots to form, mostly in the first few weeks after planting. Heat during that window is a major factor. Days above 104°F and nights above 90°F can be detrimental to storage root initiation. By late June and July, Phoenix-area days pass 104°F, and nights are in the 80s.
Research on sweet potatoes and temperature found that high temperatures shift the plant’s growth toward leaves and vines. Vine and leaf growth kept increasing with heat, while the share of growth going to the roots dropped sharply.
My spring plantings usually give me sweet potatoes. My May and June plantings grow lots of vines but don’t always produce a harvest.
Too much nitrogen
Rich soil, fresh manure, and high-nitrogen fertilizers grow lush vines. Research has linked high soil nitrogen from heavy manure use to fewer storage roots. Use compost to build the soil, and skip fresh manure and lawn-type fertilizers.
Dry soil right after planting
If the soil dries out in the first two weeks, slips form more pencil roots and fewer sweet potatoes. With desert sun and wind, new slips can dry out fast. Keep them evenly moist until they’re growing.
Soggy or compacted soil
Waterlogged soil hurts root development. Heavy, compacted soil gives the roots nowhere to expand. Loose, well-draining soil is a must.
Vines rooting everywhere
Vines that root along their length form lots of small sweet potatoes instead of a few good ones. Lift them to break those roots.
Harvesting too early
Sweet potatoes keep sizing up into fall in the low desert. If you dig in August, you may find only skinny roots. I leave mine in until late October whenever I can.
Other Sweet Potato Problems in the Desert Garden
Cracking
Cracks form when the soil swings from dry to very wet, especially late in the season. Consistent watering and mulch help. Overwatering established plants can cause it too.
Long, skinny roots
Long, skinny roots usually come from compacted or heavy soil, or from soil that dried out right after planting. Loosen the soil deeply before you plant, and keep new slips moist.
Rodents and slugs
Rodents and slugs both eat sweet potatoes underground. You often don’t know until you dig and find tubers with chunks missing or holes chewed in. Check a few plants by digging carefully in early fall. If you see damage, harvest sooner.
Whiteflies
Whiteflies show up on the undersides of sweet potato leaves, especially in late summer. A strong spray of water knocks them back. I share more ways to get rid of whiteflies in the garden in this post.
Can You Eat Sweet Potato Leaves?
Yes. Sweet potato leaves and tender stem tips are edible, and they’re one of the few leafy greens that grow through a desert summer. Cook them like spinach. We don’t eat them as often as we should.
My chickens love them too. When I’m cutting back vines or pulling the cover crop in fall, the trimmings go to the chickens. If you keep a flock, my guide to keeping backyard chickens in Arizona covers the basics.
Sweet potato leaves and regular potato leaves are different plants. Regular potato leaves are toxic, so only eat leaves from true sweet potatoes.
When to Harvest Sweet Potatoes in Arizona
Sweet potatoes take at least 90 to 120 days, depending on the variety. In the low desert, I usually leave mine in until late October if possible. They keep sizing up as temperatures ease in the fall.
The most reliable way to know if they’re ready is to dig down and check. Gently move the soil away near the main stem and look for sweet potatoes at least 2 to 3 inches across. If they’re still small, cover them back up and give them more time.
Yellowing leaves and vines are another sign that production is slowing. Harvest before your first frost. Frost damages the vines, and cold soil can damage the sweet potatoes.
Expect about 4 to 6 sweet potatoes per plant. Sometimes I get fewer, and sometimes a plant gives me a couple of very large ones instead of several medium ones.
How to Dig Sweet Potatoes Without Damaging Them
Sweet potatoes bruise and scrape easily, and damaged ones don’t store well.
- Cut back the vines first so you can see what you’re doing.
- Loosen the soil around the plant with a spade fork, starting well away from the main stem.
- Find the main crown and dig carefully around it. Sweet potatoes can spread farther from the plant than you’d expect.
- Lift them out by hand. Don’t pull them up by the vine.
- Keep them out of direct sun once they’re out of the ground.
- Don’t wash them. Brush off loose soil and leave the rest until you’re ready to eat them.
Set aside any bruised, cut, or nibbled sweet potatoes and use them first.
How to Cure Sweet Potatoes in a Dry Climate
Freshly dug sweet potatoes aren’t very sweet yet. Curing heals cuts and scrapes, toughens the skin, and gives the starches time to convert to sugars. Skip curing and your sweet potatoes will taste bland and won’t keep as long.
Sweet potatoes cure best around 80 to 85°F with high humidity, for about 7 to 14 days. Temperature is easy in Arizona in late October. Humidity is the hard part in our dry air.
I use two methods:
- Humidity domes. This is my favorite. Lay the sweet potatoes in a single layer under a humidity dome, with a damp towel or a shallow dish of water inside to keep the humidity up. Check every day for condensation or mold, and crack the lid if it gets too wet.
- Plastic grocery bags. Put a few sweet potatoes in a plastic grocery bag and set the bags somewhere warm, like near a sunny window but out of direct sun. The bags hold in the moisture the sweet potatoes give off.
Curing is done when the skin stays intact when you rub two sweet potatoes together. Don’t leave them curing too long, or they’ll start to sprout.
How to Store Sweet Potatoes When It’s Warm
After curing, store sweet potatoes somewhere cool, dark, and dry. Around 55 to 60°F is ideal. Don’t refrigerate them, because cold damages the flesh and shortens storage life.
Storage is tricky here. Most of us don’t have a basement, and our garages heat up early in the spring. Storage life drops quickly above about 70°F.
We keep ours in the garage while it’s cool in fall and winter, and we use them up before the garage gets hot. If it’s too warm out there, we move them to an indoor cupboard. Wrapping each sweet potato in newspaper and keeping them in a box helps too. Check them often for sprouting or soft spots.
Plan your harvest around storage. If you grow more than you can eat by spring, share them, or bake and freeze them. Our make-ahead sweet potato casserole recipe freezes well and is one of our favorite ways to use a big harvest.
Growing Sweet Potatoes FAQs
Plant sweet potato slips outdoors from March through June in the Phoenix area, once the soil reaches about 65°F. For a harvest, plant in March or April. Slips planted in May and June face extreme heat while they’re trying to form roots, so they often grow lots of vines with few sweet potatoes. Those later plantings make a good summer cover crop.
Most varieties need at least 90 to 120 days, and purple varieties often take longer. In the low desert, summer heat slows growth, so spring-planted sweet potatoes are usually best harvested in late October.
The most common causes are planting too late in the heat, too much nitrogen from manure or fertilizer, soil that dried out right after planting, and heavy or soggy soil. Vines that root along their length can also produce many small sweet potatoes instead of a few good ones.
Keep new slips evenly moist for the first two weeks. After that, water deeply as often as every other day in summer and less often in cooler months. Mulch the soil, and avoid keeping it soggy, which can cause cracking.
Yes. Sweet potatoes grow best in full sun, even in the low desert. Sunlight on the leaves drives the size of the sweet potatoes underground.
Space slips 12 to 18 inches apart. The vines will still spread several feet in every direction, so leave room around the planting.
Use a container or grow bag that holds at least 10 gallons. Smaller pots don’t give the roots enough room to form good-sized sweet potatoes, and they dry out too fast in desert heat.
You can grow slips from store-bought sweet potatoes, but some are treated to prevent sprouting, so organic ones tend to sprout more reliably. You won’t always know the variety, which matters for timing in the desert.
No. Regular potatoes grow from seed potatoes and are a cool-season crop in the low desert, planted in late winter. Sweet potatoes grow from slips and need the heat. Learn how to grow regular potatoes in containers in this post.
Ornamental sweet potato vines are bred for their leaves, not their roots. Any tubers they form are usually bitter and not worth eating. See how to grow ornamental sweet potato vine.
Do you add any fertilizer during growth period? and if do, what?
I usually feed lightly with Agrothrive general purpose once they are established in July. https://agrothrive.com/?ref=GITG
Hello Angela! I am in Casa Grande, AZ. I am attempting to use large 25 gallon grow bags with my sweet potatoes this year. Can I place an olla in the grow bag? I just want to make sure I am watering them correctly.
Yes, I would use an olla.
Hi Angela,
Whitney here again from St. George. I e had tons of flowers on my sweet potatoes and was hoping they would die back soon. I need the rest of that bed to plant my garlic, even though the vines are not dead do you think I will still get a harvest if I start digging them up right now so I can plant the garlic.
Hi Whitney – dig down and carefully check the size of the tubers. Then you’ll know if they are as large as you would like them to be for harvesting.
I’m about to try growing Japanese sweet potatoes (they call this variety ‘imo’, they’re a deep burgundy with cream=colored flesh that is beautifully sweet and when cooked is the texture of a ripe banana.) Has anyone here tried growing these? I picked my potatoes up for growing slips from a local Asian market. I used to eat these in Japan and have cooked the same ones that I bought to grow slips from– they’re truly delicious!
I’ve been growing sweet potato slips. Some are quite large and are starting to vine while still in the jars of water. Is there anything I can do to slow the growth. Or can they be temporarily put in pots and transplanted outside when it gets warmer. Any suggestions will be greatly appreciated. Thanks.
Hi I’ve been growing sweet potato slips. They have gotten very large. Some of them have started to vine while still in the jars with water. Is there a way to slow their growth. Or can I temporarily plant them on pots and transplant in February or March. Please help. Thanks so much.
Hi.
My sweet potato slips are very large and starting to vine while still in the jars? Is there anything I can do to slow the growth or can I plant in temporary pot until I can plant outside in my garden beds. Help please!
You can cut them in half and make two slips if you want or just trim. You could also plant in a pot while you wait. Good problem to have 🙂
Hello,
I’ve removed the slips from the sweet potato and have placed them in water to root.
If it’s warm enough, can I leave the glasses of slips outside? Or is it best to complete the rooting process inside?
Thanks so much for your help!
You can do it outside, I would avoid full sun areas if it’s really hot. Keep an eye on the water level, it could dry out more quickly outside.
First time growing sweet potatoes in the Deer Valley section of North Phoenix. I ordered 10 slips that I expect any day. Does it make sense to successive plant or all at once. If successive planting is the route I go, how do I keep the slips not planted viable. I plan to put one each in 10 gallon potato grow bags.
They are a long season crop – its best to get them all in the ground right away.
Hi Angela,
Thanks for all your helpful information. When you say sweet potatoes can take full sun, how much exposure can they take here in Phoenix? I have a bed at the inside corner of my block fence, so it’s got hot, reflecting surfaces on two sides. It also gets full sun until about 3 hours before sunset, year-round. Is that going to be too much for sweet potatoes? (I’ll be planting the first week of May.) It’s such an intense amount of sun I’m not sure what will do well in that spot. Thanks again!
I planted some slips, and a few sweet potatoes last summer. They took off quite well. Then they were an inch tall. Deer! They always attempted to regrow, and the deer would get around my protections. Aggravated me. This year, I may go full electric fence on the predators. They ate my beets, my carrots, beans, corn and anything else I had out in the garden. I planted some grapes and had those chewed up as well. Even my fruit trees and a bald cypress tree. I haven’t hunted in a while, but if I can’t harvest my veggies, I may harvest a deer or two.
[Zone 7] I had a purple sweet potato slip, Molokai, given to me in the middle of the summer. I put it in a peat pot, & it is well-rooted, but I never put it in the garden. Should I plant it in a bigger pot & keep it indoors? Put it in the garden now?
Sweet potatoes do not like cold weather, so I wouldn’t plant them outside this fall. If you can keep it alive through the winter and plant it out next spring, that may work.
Live in Lake Havasu City new to gardening in AZ. Had a great garden in high desert in Ca. Can I use the same planting times as the Phoenix area? We are a lot hotter here. Getting shade cloth for my raised beds .
Dates may be similar, not exact. Use our dates as a guide and go from there. Soil temperatures may also be helpful for you to determine planting times.
I’m in mesa, New to gardening, and I just want to say your blog will help me so much. I feel like you just saves me 5 years of trial and error. Thanks so so so much
You’re so welcome! Best of luck to you.
Good morning, I planted my slips in April, and this morning I found two big potatoes pushing up out of the ground. I wasn’t expecting to harvest until the fall. This is my first time growing sweet potatoes. Should I cover the potatoes with dirt? Leave them alone? Seems to soon to harvest. I wonder if I planted the slips too shallow. Thanks!
I’d cover them up if you don’t want to harvest right now.
do you need, or should you use a trellis for sweet potatoe vines?
I usually let mine tumble on the ground. I have seen people use a trellis for them with success.
Hi there, I’m in Gilbert, AZ! I do not have anysweet potato slips. Is there any where I can buy slips or speed up the process of making them so I can get something in th ground?
I haven’t seen any for sale. I would try using the soil method of starting slips and look for sweet potatoes at the store that are beginning to sprout – that would speed it up a bit for you.
@Angela Judd,
Hi. I have been loving your videos and information you have presented. I’ve successfully grown sweet potatoes but I’m stumped as to how to store them at 55 to 60° in Arizona. The fridge is too cold, the garage varies in temperature too much and my house is at 70°. Where do you store yours? What options do I have for storing at the required temperature for long term? I also want to grow potatoes and some more squash this year which will also need to be stored. Thank you for any help you may offer.
Hi Margaret. It’s true – it can be tough. I added some storage tips to the article. We usually store ours in the garage and use them up before temperatures warm up in the spring. Storage is definitely tricky here in the low desert.
Hi Angela! I’m in Gilbert, AZ and temps are supposed to be in the high 70s-low 80s during the day and 50s at night for the next couple of weeks. It’s not very humid, though. Would the back patio be a good place to cure these sweet potatoes right now? I’m not sure where to find a place around 80 degrees and humid without setting up a humidifier in the house but temps are only in the 70s inside, too. Thanks!
I cure my sweet potatoes by putting them in plastic grocery bags near a warm window. The bag traps the moisture and helps them cure.
Great idea! Thank you!
Can you eat the sweet potato you used to make starts when you’re done getting sprouts?
Maybe? Usually it’s pretty shriveled up by the time it’s finished, but it’s probably still edible.
I like the plain and simple honesty of this comment. No one of us can know everything or have answers to everything, and when we don’t have the answer, that means someone should try it and report back and teach the rest of us!
This is precisely the thing that is making me subscribe to your site, even though I live in New England and have a completely different set of growing conditions than you do! We should all always be learning and sharing and helping each other toward success! Good on you!!
Technically you can but scientifically you shouldn’t.
Look up how their composition changes.
My first try didn’t work out so well I planted too late. They are tiny more like green beans fat green beans. Can I still eat them?
Sure. They are edible at any stage.
So when do I start doing the slips process ?? I have to have them ready around may to June to transferred them??
It can take 2-3 months. So count back from the best time to plant for your area.
My neighbor grows the bush variety in grow bags. The bush variety yield has been smaller than the vining variety in her experience.
That’s great to know that you can grow some types in grow bags. Thanks for the feedback.
Can you grow sweet potatoes the way you do regular potatoes in those 40 gallon grow bags?
Potatoes and sweet potatoes grow differently. It may need a larger growing area, but you could give it a try. Use the largest size bag you can and fill it completely before planting the slips, rather than adding soil as the potatoes grow (as you would with regular potatoes).
Thank you very much I didn’t know you could grow sweet potatoes in the AZ. desert. I thought the climate had to be humid.So again thank you.