Unlike regular potatoes and other vegetables, sweet potatoes are not started from seed or from an older potato, they’re started from slips. Sweet potato slips are small plants that sprout from the sweet potato tuber. And they’re super easy to grow at home and without any special equipment.
The first time I grew sweet potatoes, I purchased slips from our local feed store…they cost $9! I decided right then and there to figure out how to start my own sweet potato slips.
I knew it could be done because every year I would have sweet potatoes that I bought on sale during the holidays sprout in January. And that’s all sweet potato slips are… the sprouts that pop up on a sweet potato tuber that’s been in storage too long.
How to start sweet potato slips
The hardest part about growing sweet potato slips is the timing, but I have a trick to help make that easier. Since sweet potatoes can’t be planted outside until all danger of frost has passed, you’ll need to know what the average last frost date is and then add a couple of weeks to it to be on the safe side.
To grow slips, the first thing you need is a sweet potato. This can be one you harvested last year or one you bought. If you use one from the store, try to use an organic one since some conventionally grown sweet potatoes are sprayed with a chemical, chlorpropham, to prevent sprouting.
That being said, I’ve had plenty of conventionally grown sweet potatoes sprout, so if you can’t find any organic ones, it’s worth trying to sprout conventionally grown ones.
If you find a sweet potato that is already starting to sprout, that’s an ideal candidate for growing sweet potato slips. The important thing is you want to pick a sweet potato that’s healthy looking.
Each sweet potato can grow up to 50 slips so don’t start more than two or three. If you are planting sweet potatoes to harvest for storage you’ll want to plant more than if you just want some to eat fresh. If you need help deciding how many sweet potato slips to plant to feed your family, you can get our planting worksheets emailed to you by filling out the form below.
Once you have the potato you need a warm sunny spot. This might be hard to find during the dead of winter. If you have a south facing window (if you live in the Northern Hemisphere) you’ll want to put the sweet potato near it if possible.
There are several ways to sprout sweet potatoes and each has pros and cons.
You can just put the sweet potato in the warm sunny spot and in time it will start to sprout. Be aware, this can take a month or more.
You can lay the sweet potato in a shallow pan of damp peat moss or soil and put it in a warm place. Keep the peat moss or soil damp and the sweet potatoes will sprout. This method is quicker than just putting the sweet potato in a warm sunny area but you run the risk of the sweet potato rotting or attracting fruit flies.
I think the easiest way to start sweet potato slips is to cut the sweet potato in half and put the cut end in a small bowl of water. Some people use toothpicks to suspend the sweet potato on the rim of the bowl or jar but there’s really no need for that.
Just make sure there’s always an inch or so of water in the bowl; top if off as needed. Once a week or so pour the water out and replace it with fresh water.
In time you’ll see white roots start to pop out from the cut end and little green buds starting at the tips of the sweet potatoes. Those green buds will grow into slips.
When the slips are about 5″ long you can gently remove the slips from the sweet potato. Most will not have roots so you’ll need to root them by putting them in a small glass of water until roots develop – this should only take a couple of days.
Remember I said the tricky part is the timing? You’ll have to start growing your sweet potato slips at least 2 months before you plan them outside. There are quite a few variables that you really have no control over, so they may or may not be ready when it’s time to plant.
Because of that, I like to start three months before I need to plant them outside. This allows plenty of time for the sweet potato slips to grow.
But what happens if they’re ready before it’s time to plant them outside? Plant the sweet potato slips in pots until it’s warm enough to plant them outside. They don’t each need their own pot, just put a bunch randomly in a pot of soil and when it comes time to plant them outside treat them just like any other transplant.
Plant them in loose, well draining soil after all danger of frost has past. The will need at least 100 days of frost free weather to mature. If that is a stretch for your climate, grow the sweet potatoes in large pots so you can bring them in when it frosts. Here are some sweet potato growing tips.
Sweet potato vines will usually grow well indoors and the leaves are edible. You won’t get tubers but having a pretty but edible indoor plant is also fun, especially if you live where you can’t grow sweet potatoes outdoors anyway.
Don’t forget to make notes about how you grew the sweet potato slips in your gardening notebook.