If a sweet potato starts sprouting in your pantry, this might be your sign.
I know it’s not the ideal way to remember it’s time to start slips, but here we are—February in Kentucky, and those tubers are ready whether I planned for it or not. This year I’m testing both the water method (my tried-and-true) and the soil method to see which gives me stronger slips for May planting—because in Kentucky’s Zone 7 garden, every experiment teaches you something.
Watch how I’m starting my slips this year:
Sweet potatoes take 8-10 weeks to develop strong slips, which means my February work sets up my May garden. No rush, no perfection—just paying attention and letting things grow.
Do I Need to Start My Own Sweet Potato Slips?
Short answer: Nope!
You can absolutely buy slips from reputable companies and skip the DIY route. In fact, purchased slips often come disease-free and give you access to varieties specifically bred for consistent production. If I’m buying, I go straight to the experts.
Starting your own slips is a rewarding project, especially if you’re already
winter sowing seeds in recycled containers
or planning your spring garden.
Where to Buy Quality Sweet Potato Slips
- Southern Exposure Seed Exchange – Heirloom and organic varieties perfect for our climate
- Fedco Seeds – Great selection with detailed growing information
- Steele Plant Company – Sweet potato specialists with tried-and-true favorites
- Sweet Potatoes Grow – Excellent for beginners
Most companies ship slips at the right time for your growing zone, which takes the guesswork out of timing.
But if you want the experience of starting your own (or you have sprouting potatoes demanding attention), keep reading.
When Do I Start Sweet Potato Slips in Kentucky?
The Zone 7a Timeline
I live in Zone 7a, so I start slips in early to mid-February. Here’s the math that matters:
- 8-10 weeks = time needed for strong, plantable slips
- Mid-April = Kentucky’s typical last frost date
- Early May = safe transplanting window
Starting in February gives my slips plenty of time to develop robust root systems and multiple leaves before they go outside.
Kentucky is in 3 zones, 6a, 6b, 7a. Check your zone here
Sweet potatoes are just one piece of your Kentucky garden puzzle.
Check out my complete guide to the best tomatoes for Kentucky Zone 7
for another warm-season crop that pairs perfectly with sweet potato timing.
What If I Miss February?
You can start slips through March, but you’ll be cutting it close for a May planting. Sweet potatoes need warm soil (at least 60°F), so don’t rush them outside. Better to start later and transplant in late May than to plant too early and shock tender slips with cold soil.
See the where to purchase slips above if you have missed the time frame.
Two Methods I’m Testing: Water vs Soil
After asking fellow Kentucky gardeners and researching best practices (shoutout to the UK Cooperative Extension guide), I’m using both popular methods this year. Honestly, the soil method seems faster, but in February, stores often haven’t stocked seed starting mix yet. That’s where the water method becomes your best friend.
Method 1: Starting Sweet Potato Slips in Water
This is the method I’ve used successfully for years. It’s simple, requires minimal supplies, and you get to watch the entire process unfold on your windowsill.
What You Need:
- Organic sweet potato (grocery store works if it’s organic—conventional potatoes are often treated with sprout inhibitors)
- Glass jar or container
- Toothpicks (3-4 per potato)
- Fresh water
- Sunny windowsill
Step-by-Step Process:
1. Identify the ends – Sweet potatoes have a pointy end (top) and a rounded end (root end). This matters!
2. Insert toothpicks – Stick 3-4 toothpicks around the middle of the potato, evenly spaced.
3. Suspend in water – Place pointy end UP in the jar. The toothpicks rest on the rim. Fill with water until the bottom third of the potato is submerged.
4. Find the right spot – A sunny windowsill with bright, indirect light works perfectly. Warmth speeds things up.
5. Change water weekly – Fresh water prevents rot and keeps oxygen levels up.
6. Wait for sprouts – You should see shoots emerging from the top in 2-4 weeks. Leaves follow shortly after.
7. Separate slips when ready – Once slips are 6-8 inches tall with several leaves, gently twist them off at the base and pot them up in soil.
Pro tip: Pointy end up! I can’t stress this enough. Roots grow from the bottom, slips sprout from the top. Get this backwards and you’ll wait forever.
Method 2: Starting Sweet Potato Slips in Seed Starting Mix
This year I’m trying the soil method based on what a fellow grower recommended. The University of Kentucky Extension mentions this method too, and sweet potatoes placed in moist potting soil will often grow slips in a few weeks.
What You Need:
- Organic sweet potato tubers
- Seed starting mix or potting soil
- Shallow container (4-6 inches deep works great)
- Spray bottle for gentle watering
Step-by-Step Process:
1. Choose healthy tubers – Look for firm potatoes without soft spots, mold, or obvious damage.
2. Fill your container – Add seed starting mix, leaving about 2 inches at the top.
3. Plant the potato – Bury it halfway, oriented horizontally or at a slight angle. You can also cut it in half lengthwise and bury each half cut-side down.
4. Water thoroughly – Soil should be moist but not waterlogged. I use a spray bottle to avoid oversaturating.
5. Provide warmth and light – Place near a sunny window or on a heat mat. Sweet potatoes love warmth (70-80°F is ideal).
6. Keep soil consistently moist – Check every few days and mist as needed.
7. Watch for sprouts – Shoots should appear in 1-3 weeks, often faster than the water method.
8. Separate slips – When slips reach 6-8 inches with good leaf development, carefully separate them from the mother potato and pot individually.
What Sweet Potato Varieties Grow Best in Kentucky?
According to the University of Kentucky Cooperative Extension, varieties known to grow well in Kentucky include Beauregard, Hernandez, O’Henry, Japanese/Murasaki, and Covington.
Here’s what I’ve learned about each:
- Beauregard – The standard. Copper skin with deep-orange flesh, quick maturing with good shape. This is likely what you see in grocery stores.
- Covington – Rose skin with orange flesh, superb flavor and luscious texture, with heavy yields of uniform tubers that are easy to harvest. Takes about 100 days.
- Hernandez – Bright orange skin and flesh with a tapered root that can get quite long.
- O’Henry – White skin and pale flesh for folks who want something different from the standard orange varieties.
- Japanese/Murasaki – Purple skin with drier, white flesh. A fun option if you want variety in your harvest.
If you’re buying slips, most of these varieties are readily available. If you’re starting from grocery store potatoes, you’re likely working with Beauregard, which performs beautifully in Kentucky.
Just like choosing the right tomato varieties for Kentucky’s unpredictable weather,
picking sweet potato varieties that perform well in Zone 7 makes all the difference.
What Happens Next? The May Planting Preview
Once your slips have strong roots and are 6-8 inches tall (usually by late April), it’s time to start thinking about transplanting. But that’s a whole different conversation.
In May, I’ll share:
- How to harden off slips for outdoor life
- Traditional mounding vs raised bed planting
- My spacing strategies for maximum yield
- That hanging basket experiment I mentioned
In May, I’ll share planting methods, spacing strategies, and companion planting ideas (see my companion planting series
for how I approach this).-Erin
For now, your job is simple: get those slips started. February you is setting up May you for sweet potato success.
Quick Troubleshooting Tips
My potato isn’t sprouting:
- Check warmth—sweet potatoes need 70-80°F to get moving
- Give it time—some potatoes take 3-4 weeks
- Make sure it wasn’t treated with sprout inhibitors (buy organic)
My water is getting cloudy/slimy:
- Change water more frequently (every 3-4 days instead of weekly)
- Make sure the potato isn’t sitting too deep in water
Slips are leggy and weak:
They’ll strengthen up once transplanted to soil
Move to brighter light
Frequently Asked Questions About Starting Sweet Potato Slips
In water, slips develop roots in 1-2 weeks. In soil, you’ll see sprouts in 2-4 weeks. The entire process from starting a potato to having plantable slips takes 8-10 weeks total.
Yes! Buy organic sweet potatoes—conventional ones are often treated with sprout inhibitors that prevent sprouting. If a sweet potato has already started sprouting in your pantry, that’s perfect proof it’ll work.
The pointy, tapered end goes UP. The rounded end (where it attached to the mother plant) goes down in the water. This is crucial—roots grow from the bottom, slips sprout from the top.
A single sweet potato typically produces 5-15 slips, sometimes more. Small and large potatoes produce similar numbers of slips, so don’t feel like you need giant tubers.
Yes! Gradually expose indoor-grown slips to outdoor conditions over 1-2 weeks. Start with 30 minutes of outdoor time, increasing daily until they’re acclimated to full sun and Kentucky’s spring weather.
Check three things: warmth (needs 70-80°F), time (some take 3-4 weeks), and whether it’s treated (buy organic). If it’s been a month with no sprouts and conditions are right, try a different potato.
Yes, but they establish better if you pot them in soil for 1-2 weeks first. This develops a stronger root system before the stress of transplanting outdoors.
Resources That Helped Me
I learned this process from watching other gardeners and researching Kentucky-specific information. Two resources that helped me most:
- University of Kentucky Cooperative Extension: Growing Sweet Potatoes – Free PDF with Kentucky-specific guidance
- YouTube tutorials – Visual learners benefit from watching the process (search “starting sweet potato slips” for great videos) My Go to for this process is this one HERE
The Extension guide is gold for Kentucky gardeners—it covers not just slip starting but planting dates by region, pest management, and storage.
Ready to Start Your Slips?
Whether you choose water, soil, or both methods, the important thing is getting started in February. Those slips need 8-10 weeks to develop, and May will be here before you know it.
Are you team water, team soil, or team “whatever works”? Drop a comment and let me know what method you’re trying this year.
And if you want to see my slips grow in real-time, follow along on Instagram where I share daily updates from the Kentucky garden.
Coming Soon:
- Kentucky Garden Planning for Zone 7a (coming soon)
- Transplanting Sweet Potato Slips: The May Guide (coming in May!)
- What to Plant in February in Kentucky (coming soon)
Pin this for next year! Bookmark this guide so you’ll have it ready when February rolls around again.
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