Texas is actually one of the largest producers of sweet potatoes, so you can pretty much bet this kind of plant will do well in your home garden as long it gets plenty of sun.
The sweet potato is a tropical plant and the only member of the morning glory family you might grow for food production. Even though it’s in a totally different plant family than the humble potato, it has similar needs and growing habits.
WHEN TO PLANT SWEET POTATOES IN CENTRAL TEXAS
Sweet potatoes are warm-to-hot-season plants that originated in tropical regions. They love two things: long, hot days and warm nights. Thus, warm climates like ours are the perfect place to grow them at home.
Even though sweet potatoes are actually perennial plants, we grow them as annuals because they can’t stand anything more than a light frost.
Here in Texas Hill Country, the best time to plant sweet potatoes is from April to June. Sweet potato plants won’t grow if the soil temperatures are too low, so you’ll want to wait at least two weeks after your last anticipated frost of the season. Here in the greater Austin area, our last frost is around mid-March, so we’d wait until the beginning of April to plant sweet potato slips just to be safe.
If conditions are ideal, we can expect to harvest sweet potatoes around late July.
THE BEST SWEET POTATO VARIETIES TO GROW IN TEXAS
Picking out which type of sweet potato to grow is a little different than other veggies because you won’t be seed shopping. Sweet potatoes are typically grown from slips, or vine cuttings, instead of seeds. Sweet potato slips are shoots grown from a mature sweet potato’s eye (you know, those little sprouts that pop up when you keep a sweet potato in your pantry a little too long).
Slips are genetically identical to the parent sweet potato, so if you really like a type of sweet potato you got from the store, you can try to grow your own slips (I’ll tell you how in a bit). You can also buy slips at a local nursery, garden center, or online.
Many online seed companies won’t ship slips to Texas. Slips can also be pretty expensive (upwards of $25). I’ve found it’s best to just head to a nursery near you and see what they have if you don’t want to start your own slips.
Look for popular varieties of sweet potatoes that are known to thrive here in Texas. These include:
- Vardaman (bush, or short vine, variety great for smaller garden spaces)
WHERE TO GROW SWEET POTATO PLANTS
Your prime focus should be picking a spot that gets as much sun as possible. These plants need full sun to produce. That’s at least 8 hours, but really, they’re much happier with 10 or more hours of direct sunlight.
Sweet potatoes like sandy soil. You can grow them in a raised bed or in the ground.
Growing sweet potatoes in a raised bed
Raised beds filled with well-drained soil are a great place to grow this root vegetable.
Keep in mind, though, that one sweet potato vine can quickly cover a large area and shade your other plants. I find it’s best to devote a bed to growing nothing but sweet potatoes. This is actually a great option if you’re heading out of town for the summer. All you have to do is set your drip irrigation on a timer, and your plants will be perfectly happy without you.
Growing sweet potatoes in the ground
A lot of us have clay soil in our backyards. This thick soil can hold too much moisture and cause sweet potatoes to rot or succumb to disease. Before you plant sweet potatoes, amend your native soil with coarse sand and compost to improve the drainage. You can make little planting ridges about 8″ to 12″ high to give your plants a great start.
HOW TO START SWEET POTATO SLIPS
Before planting time, you’ll need to buy or prepare your slips. This is where we see some differences between regular potatoes and sweet potatoes. With sweet potatoes, we’ll only plant the slip. Planting a whole sweet potato or even just part of one is likely to produce nothing but rot and mold.
If you’re starting your own slips, you’ll need to plan ahead. It takes about 2 weeks to sprout a sweet potato, and then those little sprouts will need about 6 to 8 weeks to mature enough to be planted.
The best time to encourage a sweet potato to sprout, then, is about 6 to 8 weeks before your last frost date. That way, the slips will be ready for planting 2 weeks after that last frost. Here in the greater Austin area, you’d want to start your sprouts in late January or early February.
The two keys to sprouting are warmth and humidity. Your kitchen is often a great place to encourage growth.
Follow these simple steps to sprout sweet potatoes:
Steps to start sweet potato slips
Buy an organic sweet potato from the grocery store or a local farmers’ market. Going with organic is important here because regular sweet potatoes are often sprayed with something called Bud Nip to prevent sprouting. In this case, we want those sprouts.
One sweet potato should grow dozens of slips, more than enough to fill your garden space.
Scrub your sweet potato clean and cut it in half (hamburger-style, not hotdog-style).
Insert toothpicks on four sides of each half so that you can suspend them over a jar of water, cut side down. You want just the bottom of the potato to be submerged.
If you have seed starting supplies, you could also place sweet potatoes in a flat without drainage holes, with some soil add a bit of water, and then set the flat on heat mats.
Place the sweet potatoes in their jars on a sunny windowsill. Watch for shoots to develop within a couple of weeks.
Once the sprouts have grown about 2″ long, you have to root them so they become little plants.
Gently break them off the sweet potato. You’ll place these sprouts in a cup of water together so that only the very bottoms of the sprouts are in water. Keep them in a sunny spot while you wait for them to develop roots. This typically happens in about 1 to 2 weeks.
You can transfer your sweet potato slips to soil as soon as they each have a couple of strong roots. Plant them outdoors if it’s the right time. If you’re still waiting on your planting window to arrive, put them in a little pot and keep them under grow lights or in a sunny windowsill.
HOW TO PLANT SWEET POTATO SLIPS
Once you’ve got some rooted slips and you’re at least two weeks past your last spring frost, it’s time to plant some sweet potatoes.
If you’re buying or ordering slips, you’ll want to get them in soil as soon as you bring them home. The best time to plant is in the evening so that the plants have some time to settle in before the heat of the day.
Follow these three steps to plant sweet potato slips:
Step 1 to plant sweet potatoes
Add 2 to 3 inches of organic matter to the top of the planting area. I like using fresh compost or worm castings. Either will give the plants enough nutrients for their entire time in your garden space.
If you’re planting in the ground, you can build up mounds with about 8 inches of soil and compost. Each mound should be about 12″ to 18″ apart in rows that are 3′ apart. This gives each sweet potato vine plenty of room to stretch out.
Step 2 to plant sweet potatoes
Dig holes about 2″ to 3″ inches deep. I like to sprinkle some MicroLife Multi-Purpose granules in each planting hole for a nice nutritional boost.
Bury each slip up to the bottom set of leaves. (You won’t bury the leaves like you might a regular potato.)
Step 3 to plant sweet potatoes
Water the planting space well to welcome your slips to their new home. You’ll want to keep the soil around these transplants moist for the first week or so while they settle in.
HOW TO TEND SWEET POTATO PLANTS
Once they’re established, sweet potato plants are super low-maintenance. Like I said, you could go out of town for a month and not worry about them as long as you’ve got the watering situation under control.
If you feel like your plants could use more nutrients, you could add some liquid seaweed every 2 to 4 weeks. I typically just leave my plants be.
Really, your only tending tasks when growing sweet potatoes will be to weed in the beginning and provide water.
Task #1: Keep the planting area weed free
This really only matters if you’re growing in the ground since raised beds typically don’t have weed issues. You’ll want to keep the area around your sweet potatoes weed free so that the plants don’t have any competition for resources.
Once the trailing sweet potato vines spread out (after about 40 days), you’ll have better ground cover and won’t have to worry as much about weeds.
Task #2: Water
Like seedlings, newly transplanted slips need daily watering to help them get established. If they feel too much stress from lack of water, you won’t end up with a high yield.
One week after they’ve been transplanted, you can cut down to watering every other day.
Two weeks after they’ve been transplanted, you can reduce to one really deep soak a week. Aim for plants to get about an inch of water per week.
If you only rely on rain to water your plants, you risk ending up with a bunch of split and cracked tubers if we experience some dry spells.
My favorite way to deliver deep, consistent water to my plants is via drip irrigation systems. This is by far the most convenient watering method if you’re growing sweet potatoes in raised beds. If you don’t already have lines installed, Garden in Minutes has a great kit that’s super easy to install.
Here’s something important to note: Stop all watering about 2 to 3 weeks before harvest time. This prevents the tubers from rotting.
WHEN TO HARVEST SWEET POTATOES
Don’t worry if your plants haven’t produced any flowers by late summer. These aren’t necessary for production, and not all sweet potato plants flower near the end of their growth cycle anyway.
If your plant does flower, it’s more like a sweet bonus. You might notice similarities between sweet potato flowers and their cousin, morning glories.
Sweet potatoes need between 85 and 120 days in good conditions to mature after being planted as slips, depending on the variety you’re growing.
One good sign that your sweet potatoes are ready for harvest is when the leaves turn yellow or look like they’re dying. That indicates the root system is mature, and you shouldn’t expect any more growth below ground.
If you got a late start on your sweet potato crop and are expecting your first frost of fall, go ahead and harvest before the freeze.
As a reminder, stop watering your plants the last few weeks before harvest.
HOW TO HARVEST SWEET POTATOES
If possible, wait for a sunny day when the soil is dry to harvest your sweet potatoes. Sweep vines to the side so that you can see the base of the plant. (Or just cut the vines and clear the area.)
Use a hori hori, a small shovel, or a digging fork, if you have one, to dig down about 12″ to 18″ away from the base of each plant.
The sweet potatoes you’re used to handling from the store have been cured. The ones you’re about to dig up have not. That means their skin is super delicate, very prone to bruising and tearing. (Damaged sweet potatoes aren’t great for storing.) You’ll need to be super careful when digging them up. You’ll even want to place them gently in your harvest bucket instead of tossing them.
Once you’ve dug down about 6″, it’s best to use your hands to dig toward the middle of the plant. Gently lift each sweet potato out of the ground.
Lay them flat somewhere to dry under the sun for about an hour before bringing them indoors. You can brush dirt off their skin (gently!) but avoid washing them.
HOW TO SAVE AND ENJOY SWEET POTATOES
Your sweet potatoes will need to cure for about 7 to 10 days before you eat or store them. Curing gives them time to turn all their sweet potato starches into sugar. It also toughens up their skin a bit so you don’t have to worry about injuring them so easily.
How to cure sweet potatoes
The best place to cure them is somewhere warm (about 85 degrees) and humid. I like to put my sweet potatoes in single layers inside plastic grocery sacks. Loosely tie the sacks closed, leaving some gaping around the knot for air ventilation. Put these bags in a sunny spot indoors (a bathroom is ideal).
Another option is to cure sweet potatoes in a closet or bathroom with a space heater set on low and either a humidifier or a bucket of water.
How to store sweet potatoes
Sweet potatoes will keep for 5 to 8 months after being cured. The best spot to store them is somewhere cool but not a fridge or freezer. You only want to refrigerate cooked sweet potatoes.
The part that we eat is basically the storage roots of the plant. That means two things: One, sweet potatoes are made to keep for a long time, and two, sweet potatoes are filled with lots of essential nutrients.
How to enjoy sweet potatoes
It bears repeating: Sweet potato roots are super nutritious. They’re rich in beta-carotene (which we convert to vitamin A), vitamin C, and manganese. Sweet potatoes with orange flesh especially have lots of beta-carotene, an antioxidant that can help protect us from chronic illnesses. These little roots also improve our immune systems, making them the perfect food to eat over winter during cold and flu season.
My favorite way to enjoy them is to make sweet potato fries or sweet potato casserole. (I search for a Ruth’s Chris copycat recipe online and then halve the sugar.)
I also love a baked sweet potato with some black beans, plain yogurt, and cilantro on top, plus a good squeeze of lime juice. So yummy!
LETTUCE HELP YOU GROW
Here’s to growing bushels of sweet potatoes right in your backyard.
Let us know in the comments if you have any questions! We’re here to help you grow!