Growing Sweet Potatoes

Sweet potatoes are not grown from seed. They are grown from rooted slips. A slip is a propagated rooted cutting from a plant.

Sweet potatoes are not potatoes but a member of the morning glory family. If you look at the leaves you can see the resemblance.

Sweet potatoes in Colorado need at least 4 months of full hot sun with plenty of water to produce a crop. They take a long time from start to finish with a few little tricks in between.

I start my potato slips in Jan/Feb because it takes a long time to get the potato to sprout. I harvest and root the sprouts, then continue growing them indoors, increasing the roots.

I have tried a couple of different ways of starting the slip.

The toothpicks and water way is to put the toothpicks into the potato and suspend the potato in water until the potato sprouts and you can harvest the slips.

The soil method is easy. Place the whole potato in a bin or pot and cover the bottom half of the potato, leaving the top half exposed. Water the soil so it is wet, but not soggy. Sometimes I will use a pan and cover with plastic. I like to use the seed tray and dome with the heat mat. These are the same tools I will use to cure them after harvest.

I prefer soil over toothpicks and water. It seems that the soil works faster. Both ways sometimes end up with the potato rotting, so I like to start a few potatoes of each variety to hedge my bet.

I plant the rooted plants outside the beginning of June in black buckets with good soil mixed with potting soil. 7 gallon size being the smallest bucket I use. The bigger the bucket, the better they produce. The black buckets absorb the heat and respond like a tropical environment. The buckets are placed in the hottest sunniest part of my yard.

Sweet potatoes are not regular potatoes and do not need to be planted as deep. Bury the slips 2-3 inches below the soil with the leaves out the top. Water well using either a granular or liquid root stimulator. I fertilize my sweet potatoes every month and quit in August. Since they are in pots, there isn’t many nutrients available. In the ground you wouldn’t need to fertilize as often. I try to mix up my fertilizers, but still try to keep with a 1-2-2 ratio.

Harvest begins when the threat of frost is against me, and by then the plants have quit growing. The bucket is emptied on a tarp, and the largest roots that are kept. The smallest roots are used in a mashed sweet potato casserole. The larger ones I use for baking or making sweet potato pie.

Once harvested, they are cured to get a sweeter potato. This is accomplished using a seed tray, humidity dome and heat mat.

Curing them with 80 degree temperature and 80 humidity for 5-6 days will cause a reaction in the potato and keep them sweeter. Curing doesn’t only give you a sweeter potato, but extends the shelf life of the crop. You will know if they are cured by the hardness of the potato.