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.
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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.
Cons: Takes longer; requires frequent changing of water.
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
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.
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.
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.
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).