Sweet potatoes aren’t grown from seeds like most vegetables, or even seed potato chunks like potatoes are. Sweet potatoes are grown from small seedlings, known as slips. It’s very simple and inexpensive to sprout your own!
When to Start Sweet Potato Slips
The timing is important if you want to grow large and tasty sweet potatoes. This plant loves warm weather and should be planted when the soil reaches 65 degrees. The slips take about 4-6 weeks to mature, so you should be starting sweet potato slips indoors about six weeks before the last frost date in the spring, about mid-April here in the Northland.
SOIL METHOD (FASTER): This method usually takes around 4-6 weeks.
- Poke holes in the bottom of a foil pan for drainage.
- Fill the foil pan with moist potting soil or seed starting mix.
- Nestle sweet potatoes in soil, covering about half the potato with soil.
- Place the foil pan on top of its lid to contain drainage.
- Place the pan on a warming mat, on top of the refrigerator, in the heat from a grow light or near a sunny window.
- Keep soil moist as roots and sprouts form.
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.
Scroll down to “How to Remove Sprouts” to see the rest of the directions.
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SUSPENDING METHOD (SLOWER): The suspending method often takes 6-8 weeks (or more) to produce slips.
- Simply put toothpicks into the top 1/4 of the sweet potato and suspend in water. The rooting or pointy end should go in the water. Here are a few ways to determine the difference between the rooting end and the sprouting end:
- One end will appear larger and bulbous. This is the sprouting end.
- The end of the sweet potato that tapers is typically the rooting end.
- Look for thin roots on one end. This is 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 will speed up the process.
- Keep the water level up in the jar and keep 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, follow the directions below.
How to Remove Sprouts
When sprouts are about 5-6 inches tall, remove them by carefully twisting or cutting them off the potato. These are now called slips.
- Remove lower leaves from the slips and place in a jar of water to root them. Roots will develop quickly; you should begin to see them in 1-2 days.
- Keep the jar in a warm, bright place to 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 water fresh. Discard wilted or rotten slips.
Once roots are fully formed and several inches long, it’s time to plant! Plant rooted sweet potato slips in your garden bed or containers about 12-18” apart and 4” deep.
