Growing sweet potato slips is easy! A single sweet potato can grow dozens of slips. We usually grow about two to three hundred pounds of sweet potatoes a year from just 40 slips.
Growing sweet potatoes from seed is an enjoyable and rewarding gardening experience. With just a bit of knowledge, you can easily grow these nutritious root vegetables in your own backyard. In this comprehensive guide I’ll walk you through everything you need to know from choosing the right variety to harvesting your crop. Whether you’re a seasoned gardener or planting for the first time, let’s dig in and learn how to grow sweet potatoes from seed!
Selecting the Best Sweet Potato Variety
The first step is choosing which sweet potato variety to grow. There are hundreds to choose from but generally they fall into two main categories
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Orange-fleshed – These have orange flesh and skin are sweeter in taste, and contain more beta-carotene. Popular orange varieties include Beauregard Centennial, and Jewel.
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White-fleshed – These have white or pale yellow flesh and drier texture. They’re less sweet but have a more potato-like taste. Some common white varieties are O’Henry, Bonita, and White Triumph.
Consider your climate when selecting a variety. Choose an early maturing type if you have a shorter growing season. Talk to local gardeners to see which varieties grow best in your area.
I recommend trying a few different kinds to see which you like best! Good ones for beginners are Beauregard and Jewel.
Starting Slips from Sweet Potato Roots
Growing sweet potato slips from roots is easy and the most common way to start plants. Here’s how:
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1. Purchase certified disease-free sweet potato roots from a garden store or online retailer. Regular grocery store potatoes may harbor diseases.
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2. Cut the roots into 2 inch chunks, making sure each piece has a couple buds or “eyes”.
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3. Place the root chunks sideways in jars of water so the bottom half is submerged. Put them in a sunny spot and change the water every 2-3 days.
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4. Slips will begin sprouting in about 2 weeks – these are stems growing from the buds. Once they reach 5-7 inches tall, they’re ready to plant outside.
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5. Carefully twist or cut off the slips close to the root. Avoid damaging the roots so they continue producing slips.
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6. Place slips in a cup of water until you’re ready to transplant them in the garden.
Root chunks can yield 10-20 slips each. Stagger planting a new batch every 2 weeks for a longer harvest.
Planting Slips in the Garden
Sweet potatoes require warm soil and air to thrive. Transplant slips outdoors after all danger of frost when soil temperature reaches 65°F. Follow these steps:
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Bed Preparation: Build raised soil beds that are 8-12 inches tall. This allows the soil to warm faster. Cover beds with black plastic mulch 1-2 weeks before planting to help heat the soil.
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Planting: Poke holes 6-8 inches apart in the mulch, then transplant slips into holes. Bury the lower 2-3 inches of each slip. Water well after planting.
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Ideal Conditions: Sweet potatoes grow best in full sun. Space rows 3-4 feet apart for vine varieties. Bush types can go 2 feet apart.
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Fertilizer: Work compost or balanced fertilizer (10-10-10) into soil before planting. Side dress with nitrogen fertilizer 4 weeks after transplanting.
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Water: Keep soil consistently moist but not saturated. Use drip irrigation or soaker hoses to water at soil level. Avoid overhead watering.
With the right conditions, slips will quickly establish roots and start growing vines along the ground.
Caring for Sweet Potato Vines
Once your slips are happily growing, there are just a few things needed to keep vines thriving:
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Weed Control – Mulch heavily with straw to smother weeds. Gently hand pick any that sprout around plants.
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Vine Training – For bush types, no training is needed. Vining varieties may need help spreading across rows.
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Hill soil – When plants are 12 inches tall, pile more soil around bases to prevent tubers from growing above ground.
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Pest Management – Watch for caterpillars, beetles, aphids and other pests. Remove by hand or use organic insecticidal soap sprays.
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Water – Supply 1-2 inches of water per week. More is needed in hot, dry weather. Proper moisture prevents misshapen tubers.
With minimal care, vines will rapidly spread and produce an abundance of sweet tubers underground!
Harvesting Sweet Potato Roots
Sweet potatoes take 90-170 days to reach full size, depending on the variety. Use these tips for the best harvest:
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Time – Dig roots after vines turn yellow or are killed by frost. Waiting too long allows them to over-mature.
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Harvesting – On a sunny day, gently dig tubers with a spading fork. Take care not to stab or bruise them.
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Curing – Place roots in a warm, humid area (80-85°F) for 10-15 days. This thickens skins and converts sugars to starch.
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Storing – After curing, move tubers to a cool spot (55-60°F) with high humidity for long term storage. They will keep 2-6 months.
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Uses – Enjoy fresh boiled, baked, or mashed. Prepared roots also freeze well for longer storage.
With the satisfaction of biting into your first homegrown sweet potato, you’ll be hooked! The work of raising them from seed will feel very rewarding.
Troubleshooting Common Problems
Even experienced gardeners run into issues sometimes. Here are solutions to a few potential problems:
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Slow slips – If roots are rotting or sprouting slowly, the water may be too cold. Move them to a warmer area.
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Weak plants – Spread more fertilizer around plants if growth is stunted. This adds nutrients to soil.
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Spotted leaves – Leaves with brown spots could indicate fungal leaf spot disease. Improve airflow and avoid wetting leaves when watering.
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Misshapen roots – Poor soil drainage causes twisted or stubby roots. Build raised beds to improve drainage.
Don’t get discouraged! With attentive care and optimal growing conditions, you can achieve a bountiful harvest of homegrown sweet potatoes.
Enjoy Your Sweet Potato Harvest
Two Methods to Grow Sweet Potato Slips
There are two common ways to grow sweet potato slips. The water method and the soil method. Even though the water method is popular, the soil method is the preferred method. Growing sweet potato slips in soil cuts the time needed to grow them in half.
With either method, as sweet potato slips are taken off the potato, the potato can be left in the water or soil for a longer time and new slips will continue to grow in the same place.
The downside of taking multiple slips off one sweet potato over a long period of time is that they will be at different stages of growth.
On a personal note, I put 10 sweet potatoes in soil to grow 40 slips. I do this so there are enough slips at a similar stage of growth and I can plant them all at once in the garden.
For the water method, a jar is filled part way with water. Then a whole sweet potato is poked with several toothpicks in the center. Place the rooting side of the sweet potato in the water. The toothpicks should rest on the top of the jar and the sweet potato end is suspended in the water. Take the whole thing and place it by a sunny window.
This method takes 4-8 weeks (sometimes even longer!) until slips are full size. Once they are full size and have a few leaves, break the stem off the sweet potato and place it in a container filled with moist potting soil.
The stem should be buried an inch or so in the potting soil. But take care to keep the leaves above the soil level. This process allows the slip to form roots.
Once the slip has formed roots, it can be hardened off (see method below) and planted in the garden.
The Soil Method (Preferred)
For the soil method, whole sweet potatoes are placed flat in a container or tray. Then pour moist seed starting soil mix over the top and level it. It’s best for the sweet potatoes to be fully covered with soil.
However, if your tray is shallow the only essential parts of the sweet potato that need to be covered are the pointy end and opposite end. If a little bit of the widest part shows above the soil that’s ok!
Then the tray is placed under grow lights, in a greenhouse, or near a very sunny window. Keep the soil moist but not soaking during this time. Sweet potato slips form in 3-4 weeks.
A huge benefit of the soil method is newly grown slips form roots in the soil as they grow. This cuts out an entire step of rooting the slips. If the slips already have roots, they can be planted directly into the soil or planted in containers until they are ready.
With either method, the final step is to harden off the sweet potato slips. For those unfamiliar, this means that the plant and leaves need to get used to being outside in the sun, wind, and other elements.
To harden off sweet potato slips, place them in a container and cover the roots with a moist seed starting soil mix.
When the temperature is warm enough outside, take the slips out for a half hour and place them in the sun. Then bring them back inside. The next day take them out for one hour, then bring them back inside. The third day take them out for three hours, then bring them inside.
Increase the time by an hour a day until a full eight hours is reached. After that you can plant if it’s warm enough, see below for when to plant.
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FAQ
Can I grow a sweet potato from a sweet potato?
Can I just plant a sprouted sweet potato?
Yes. Then plant the sprouts when it’s not going to freeze anymore. The warmer the better. You don’t really need to root them much. The sweet potatoes grow down, not up like normal potatoes. So just plant em and wait.
What is the best month to plant sweet potatoes?
Before planting sweet potatoes, you should also consider the right time to plant them. This will vary according to the area you are in, as they thrive in warm climates. It is best to plant them between April and June.