If you have a sweet potato that is going bad on one side but has a few sprouts and is still firm on the other, cut off the bad end, then continue on with the following steps.
1 sweet potato
If you have a sweet potato with a few little sprouts/leaves stick it in a cup and add water until it is ¼- ½ way up the side of the sweet potato. Make sure any leaves sprouting are on top of the potato and not in water.
If there aren’t any sprouts forming, I like to stick toothpicks in the side of the sweet potato so they rest on the edge of a cup or jar, then fill with water about ½ up the sweet potato.
Change the water once a week and watch as roots begin to form. This can take 2-3 weeks. Once you have roots, plant in well-draining garden soil and water 2-3x a week.
Harvest sweet potatoes when the ends of the vine start to turn yellow or just before the first frost, this is typically around 100 days after planting.
Notes
Tips and Tricks
I have also successfully just planted sweet potatoes that had sprouted from sitting on my table, straight into soil, without developing roots in water first.
This is by no means a full guide on growing sweet potatoes and is just a fun experiment to do if you have some sweet potatoes going bad or sprouting.