It has been a few years since I grew sweet potatoes in the garden, and since all 3 of the kids love them, I decided to give it a go again. You can purchase slips at the nursery, but I thought it would be a fun project to do with the kids to sprout them ourselves. I bought 8 at the grocery store a month or so ago. The kids poked toothpicks into them and we set them into jars of water. The jars have been sitting in the seedling window in our kitchen. After a couple of weeks, some of them started to send down roots in the water. A few days later, some of the sweet potatoes started to sprout buds on their top sides. We now have a germination rate of 80%-ish. Not too bad considering that tubers sold in the grocery store are usually treated with a substance that is designed to prevent them from sprouting. Given our success, I might buy some more this weekend since they are on sale for $.49 a pound.
Sweet Potatoes are originally a tropical plant, so they like plenty of warmth. I'm going to put down black weed barrier to help warm the soil. I also recall seeing a video on youtube once where a guy was growing them under a plastic tunnel to boost temperatures. I think St.Louis gets hot enough on its own during the middle of summer, but I might try it out early on.
Darius over at "Gardening Along the Creek" recently posted about trying to start sweet potato slips in potting soil instead of water. She's putting them on top of a heat pad to boost temperatures and promote sprouting. That's an idea I might try in the future. It would be interesting to see how the germination rates/speed varied with and without additional heat. Even if I don't try that, I'm curious to see how many pounds of tubers I get back from a $4.50 investment.