
Sweet potatoes aren’t grown from seed – they are grown from slips. A slip is a rooted sprout from a mature sweet potato. You can order sweet potato slips online, or you can grow your own. If you’re wondering how to grow sweet potato slips, you’ve come to the right place.
Begin the process about 8-12 weeks before your planting date for sweet potatoes. Here in the low desert of Arizona, our planting window for sweet potatoes is from March – June.
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How to grow sweet potato slips: Choose which method you would like to use
There are a few methods for growing sweet potato slips. I’m sharing three successful methods I’ve used.

1. The Traditional Water Method
The traditional method of making sweet potato slips is suspending the sweet potato in water. This method works, but often takes 6-8 weeks (or more) to produce slips.
Choose this method if you have plenty of time before you plant and don’t have indoor lighting. A bright window works well for this method.

Pros: Simple
Cons: Takes longer; requires frequent changing of water.
Jump to instructions for the traditional water method
2. The Indoor Soil Method
In my experience, the indoor soil method of making sweet potato slips is a much faster way to make sweet potato slips. This method usually takes around 4-6 weeks.
Choose this method if you would like slips faster, and you have bright indoor lighting available.

Pros: Quickest method
Cons: Requires indoor lighting & heat mat for best results. Must keep the soil moist. Chance for potato rotting.
Jump to the instructions for the indoor soil method
3. The Outdoor Soil Method
The outdoor soil method of making sweet potato slips works best in warm climates. This method takes 4-6 weeks once the soil is warm enough.
Choose this method if you have a long growing season and don’t want to bother with starting slips indoors.

Pros: Easiest method; does not require any upkeep if your garden is already being watered.
Cons: Soil must be warm before you begin. Areas with short-growing seasons may not have enough time to produce slips.
Jump to the instructions for the outdoor soil method
Before you begin:
The first step for all three methods is to choose a healthy organic sweet potato. Organic potatoes are less likely to be treated with a sprout inhibitor.

Do you have a sweet potato beginning to sprout in the cupboard? Perfect! Now you have a head start in whichever method for sprouting sweet potato slips you choose.

1. Traditional “water method” of making sweet potato slips

Suspend half the sweet potato in a jar of water using toothpicks.
Does it matter which half of the potato is submerged in water when making sweet potato slips? Yes, the rooting end should go in the water. Here are a few ways to determine the difference between the rooting end and the sprouting end:
- Look for small thin roots on one end. This is the rooting end.
- One end may be larger with more eyes. This is the sprouting end.
- The end of the sweet potato that tapers is typically the rooting end.
You want the bottom (rooting) half to be immersed in water and the top (sprouting) half above the jar. Roots will form in the water, and sprouts will form in the top part of the potato.
Providing warmth (a seedling warming mat or on top of the refrigerator) and light (a grow light or sunny window) will speed up the process considerably.
Keep the water level up in the jar and keep the water fresh by replacing it every week or so. Within a few weeks, roots will develop first, and then sprouts will start to form on the suspended potato.

Once several 5-6 inch sprouts have formed, see the rest of the directions below.
2. Faster “indoor soil method” of making sweet potato slips


- Poke holes in the bottom of a foil pan.
- Fill foil pan with potting soil or seed starting mix.
- Moisten soil.
- Nestle sweet potatoes in soil, covering about half the potato with soil.
- Place the lid under the pan to catch any excess water coming out of the holes.
- Keep soil moist as roots and sprouts form.

Once again, providing warmth (a seedling warming mat or on top of the refrigerator) and light (a grow light or sunny window) will speed up the process considerably.
If the sweet potato becomes soft or rotten, you may need to begin again.


In about a week, if you wiggle the sweet potato, you will feel that roots are forming in the soil. Within another week or two, small sprouts will begin to grow from the top of the sweet potato. Once several sprouts have grown to 5-6 inches long, remove the slip.

You may be able to remove the slip with roots attached. If so, you can go ahead and plant. If there are no roots, go ahead to the next step.
3. “Outdoor soil method” for making sweet potato slips

- Check soil temperature. Once the soil is at least 65°F (18°C), you can begin.
- Moisten soil. This is the soil thermometer I use.
- Bury the bottom (rooting half) of sweet potatoes in the soil, covering about half the potato with soil.
- Use a milk jug or cloche to warm the soil and encourage rooting and sprouting.
- Keep soil moist as roots and sprouts form.
If at any time the potato becomes soft or rotten, you may need to begin again.

Within a week or two, if you wiggle the sweet potato, you will feel that roots are forming in the soil. Within another week, small sprouts should begin to grow from the top of the sweet potato.

Once several sprouts have grown to 5-6 inches long, remove the slips from the sweet potato and begin the next step.
Whichever method you choose for making sweet potato slips (the water method or either soil method), the next steps are the same:
- When sprouts are about 5-6 inches tall, remove sprouts from the sweet potato by carefully twisting off or cutting off at soil level.
- Remove lower leaves from sprouts and let “root” in a jar of water. Roots will develop quickly; you should begin to see roots in 1-2 days.
- Placing the jar on a seed germination mat for warmth and under a grow light will speed up the process of developing roots.
- Keep the water level high in the jar. Switch out the water about once a week to keep the water fresh. Discard wilted or rotten slips.
- Once roots are fully formed and several inches long, it’s time to plant.
- Plant the rooted sweet potato slips about 12-18 inches apart and 4 inches deep.
- Water newly-planted slips well and feed with a starter solution high in phosphorus to ensure the plants continue rooting.




One sweet potato will produce a dozen or more sprouts. Allow sweet potato to continue rooting and producing slips until you have as many as you (and your neighbors) need.


Once you’ve grown sweet potato slips, learn how to grow sweet potatoes in this blog post.

- PLANTING GUIDE: Each month lists vegetables, fruit & herbs to plant outside & seeds to start indoors.
- HARVEST GUIDE: Photos show what may be ready to harvest that month.
- Planting dates are for the low desert of Arizona (zone 9b).
If this post about how to make sweet potato slips was helpful, please share it:


Danette
Thursday 27th of April 2023
Hi Angela! I am doing the soil method and have the potatoes set up under lights & on a warming mat as specified. I bought organic sweet potatoes and got everything set up one month ago. I've kept the soil moist. Nothing has happened so far. At what point do you throw the potatoes out and try again?
Angela Judd
Friday 28th of April 2023
If the potatoes are still firm hopefully they are rooting in the soil - give them a little jiggle and see if they are firming up in the soil. They often develop roots first and then sprouts.
Chuck
Monday 24th of April 2023
Hello and thank you for the tutorial. I started several different types sweet potatoes in potting soil under grow lights. After a few weeks, the all became very soft to the touch. Will they produce or should I start over?
Angela Judd
Friday 28th of April 2023
They rotted. Start over.
Dan
Wednesday 19th of April 2023
I appreciate your insights on sweet potatoes, but I have a question. Last fall, I harvested sweet potatoes that I grew in a large container. However, I kept one of the large vines (after removing the potatoes) and stuck the end in a 5-gallon bucket of water and have maintained it through the winter months . . . lots of root growth and the vine portion appears to be healthy. The vine has become "thicker" but not longer (for whatever reason). The question I have is, can I cut the vine into pieces say, 4- or 5-inch, place those pieces (with possibly some leaves attached) into some water, and expect those portions to root or should I just put that one large root mass with the entire vine into the ground/container?
Angela Judd
Friday 28th of April 2023
I'm not sure what the difference would be. You could always try it with a couple and experiment.
Kay
Saturday 15th of April 2023
I started by sweet potatoes in mulch in a plastic container and I have let them grow really tall before I was given your podcast from a friend. The slips are very tall with lots of leaves. I am worried that they are too tall and I will not have very many to plant. Can the slips be cut in pieces and put in water to be able to have more slips? I appreciate your information.
Angela Judd
Tuesday 18th of April 2023
I would keep the slips as is. The sweet potato will continue producing slips and you should have all you need before long for planting.
Sue
Saturday 11th of March 2023
I live in Tucson and have some soil slips growing. I need to know the best things; best container in which to grow and how much direct sunlight will it need? Our yard has a lot of rock mulch and gets very hot in summer. I do have some spots the morning Sun and afternoon shade. Would this be best?
Angela Judd
Saturday 11th of March 2023
You'll find more growing information here: https://growinginthegarden.com/how-to-grow-sweet-potatoes/ At least a 10-gallon container. Morning sun with afternoon shade is great if you can.