You can create slips from a sweet potato using two main methods. The water method suspends the tuber in a jar with toothpicks. The soil method buries it halfway in damp potting mix. Both work well, but I've found the soil method gives you stronger slips with better roots.
I start my sweet potato slip propagation indoors about 8 weeks before the last frost each spring. The first year I tried it, I used the water and toothpick method on three tubers. The slips grew fine but looked thin and weak when I pulled them off. The next year I switched to burying tubers in soil and the slips came out thicker with roots already forming at the base. That switch made a huge difference at transplant time.
Slips need steady warmth of 70-80°F (21-27°C) to wake up the dormant buds on the tuber. A warm spot near a sunny window works great for this. Once buds appear, green shoots push up fast. Utah State says slips are ready to pick when they reach 6-8 inches tall with 4-5 leaves on each stem. At that size they have enough energy stored to survive on their own.
USDA research shows that one sweet potato can produce up to 50 slips over several harvests from the same tuber. Just twist or cut the slips off when they hit 8-10 inches and the tuber will keep growing new ones. I got 30 slips from a single large tuber last season by harvesting in batches over six weeks.
Water Method Sweet Potato Slips
- Setup: Push 3-4 toothpicks into the tuber's middle and rest it in a jar so the bottom half sits in water.
- Care: Change the water every 2-3 days to prevent bacteria and keep the jar in a warm, bright window all day.
- Timeline: Expect sprouts in 1-2 weeks and harvest-ready slips in about 4-6 weeks from the start date.
Soil Burial Method
- Setup: Bury the tuber halfway in a tray of damp potting mix and press it down so it stays in place.
- Care: Keep the soil damp but not soggy and place the tray on a heat mat or warm spot near 75°F (24°C).
- Timeline: Sprouts show up in 1-3 weeks and slips are ready to harvest in about 5-7 weeks total.
Start growing sweet potato slips indoors 8-12 weeks before your planned outdoor planting date. This gives you plenty of time for the slips to reach full size. Mark the date on your calendar and count backward from your last frost date. In most areas, that means starting in March or early April.
Once your slips hit 6-8 inches, twist them off the tuber and stand them in a cup of water for a week. Roots will grow from the base and the slip will be ready for the garden. Harden them off outside for one week before planting by setting them in a shady spot during the day. Bring them inside at night if temps drop below 50°F (10°C).
The whole process is simple and costs you almost nothing. One sweet potato gives you enough slips to fill a whole garden bed. You'll enjoy watching those green shoots push out of a plain tuber every spring. The water method sweet potato slips grow well, and the soil method gives you even stronger starts for your garden.
Your best bet is to try both methods your first year and see which one you like more. Set up two or three tubers in water jars and bury two more in soil trays. Compare the results at harvest time and stick with your winner going forward. Either way, you'll end up with more slips than you know what to do with by planting day.
Read the full article: Growing Sweet Potatoes: Full Guide
