How to Grow Sweet Potato Slips

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.

What are sweet potato slips?

Sweet potato slips are the shoots that grow from a mature whole sweet potato. The new growth or sprouts can be cut or broken off the sweet potato to form a “slip”. 

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What type of sweet potato do you need?

An organically grown sweet potato is best for growing slips. Most sweet potatoes aren’t sprayed with a sprout inhibitor because they are less likely to sprout than a regular potato. However, an organic sweet potato is a better choice because you can be certain it will sprout. 

Also, an organic sweet potato will have less chemical inputs and the slips coming off of it are more likely to thrive in the home garden setting.

Slips can also be grown from last year’s harvest of your own sweet potatoes or a neighbors! 

There are many sweet potato varieties to choose from for growing. My personal favorite is Beauregard. 

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.

The Water Method

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.

Hardening off Slips

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.

When to Plant Sweet Potatoes

The best time to plant sweet potatoes is when the soil temperature consistently stays above 60ºF (15ºC).

If you don’t have a way to test soil temperature, plant sweet potatoes two weeks past your average last frost. 

Use CAUTION! Sweet potatoes hate cold temperatures and the plants will be damaged if the soil temperature drops below 55ºF.

Got a Late Start And Want to Buy Slips Instead? 

If you got a late start this year and didn’t realize it takes a long time to grow slips, you purchase them. Here’s where I recommend buying sweet potato slips for your first year. They are relatively inexpensive and you can skip the extra work.

More Information on Growing Sweet Potatoes

After your sweet potatoes are planted and growing, here’s my guide to help you know when to harvest sweet potatoes.

I also share all my secrets for growing huge sweet potatoes!