Growing Sweet Potatoes

Sweet potatoes are a healthy and filling food, not to mention versatile and easy to prepare. We eat them several times a week in our home. They are a low maintenance crop to grow, but they do require heat, a fairly long growing season, and lots of space. Read on to learn how to easily grow this staple crop.

Propagation

In certain parts of the country you may see sweet potato slips available at nursery, but you can save money by sprouting them yourself. We usually begin this process 2-3 months before it is time to plant them out.

Start by purchasing organic sweet potatoes, they must be organic as sometimes the conventional ones will be treated with chemicals to keep them from sprouting. There are several ways to get them to sprout, my favorite is to cut them in half and place 1/2 of each sweet potato into a jar of water. I like to use large jars for this, as the larger they are the better the root system on the seed potato will be. Any size jar will work though! Use toothpicks to suspend the tubers. The water should come about half an inch over the bottom of the tuber.

Another way of doing this is to cut them in half the long way and place them cut side down into a seed tray. Cover them lightly with dirt and keep them moist.

Place them somewhere where they will get a good amount of sunlight and warmth everyday, sweet potatoes are a heat loving crop and they will grow faster the warmer they are.

Within a couple of weeks there should be sprouts on your sweet potato. When the sprouts are 6-8 inches long with several leaves gently pinch them off of the tuber and place into a jar of water so they can sprout roots of their own. Continue to do this until it is warm enough to plant them out. It is ok to put several slips into one jar, but don’t crowd too many as the roots will begin to tangle together. Also, make sure the tubers and the new slips get fresh water every week or so.

When To Plant Them

Sweet potatoes like it hot. They will not die in cool temperatures (as long as they are above freezing) but they will not really grow either, so don’t worry about getting them planted in the early mad rush of Spring. Instead, just keep propagating them and putting the slips into jars of water. If you grow more than you need give some to a friend! I usually get mine into the ground around mid May. The days should be warm and the nights should be above 50 degrees.

How to Plant Them

I plant the slips out about 15 inches apart. They like a loose sandy soil best, but we have clay soil where we live so we add lots of wood chips and compost. The beds the slips are planted in should be well mulched to preserve moisture.

I plant out the slips, and I plant out my starter potatoes that I grew all my sprouts on as well.

Care

Sweet potatoes are a fairly low maintenance crop. When the slips are first planted they should be watered daily for the first week, until established. After that they really only need to be watered if they are looking wilty and sad, they don’t require a ton of water. The vines grow quickly and once they start to spread feel free to harvest some to eat, the leaves are tasty (we cook ours like spinach) and they are nice to have around in Summer when it is too hot for lots of other greens.

When to Harvest

Sweet potatoes need at least 4 months of hot weather to form a decent size tuber so do not harvest before that, I like to try to wait 4 1/2 months or longer if the weather cooperates. They definitely need to be harvested before the first frost, freezing can damage them and make them susceptible to rot. When the days are not staying consistently above 80 degrees it is time to harvest them, in my area that is about mid-October. Another clue it is time to harvest them is that the vines will begin to turn yellow.

Follow the vines to the place they are connected to the dirt and gently loosen the soil. Hand tools can be used, but be careful as the potatoes are easy to scar at this point. I like to harvest them on a warm day and lay them all out on a garden bed for a few hours, this helps to start the curing process. I separate them by size (huge, normal size, and tiny) and pack them into boxes or baskets. Wipe the dirt off of them gently, but do not wash them. They will not store well if they are washed.

Curing

For the starches in the sweet potatoes to turn sweet they must be cured properly. They like a warm (80-90 degrees) and humid environment. We just cure ours in our tiny mud room because there is a lot of humidity where we live. We stretch a curtain across the area so it does not get cooled by the AC and it works great. You could also cure them in a bathroom by closing air conditioning vents and even adding a space heater if necessary. Bathrooms tend to have more humidity than other rooms of the home. This process takes a week or two.

Then the potatoes can be kept at about 55/60 degrees and they will continue to cure for a couple of months. Again we tend to keep them in our mud room because the weather begins to cool and it is around that temperature anyway if we don’t let the heat from the rest of the house in. A root cellar or garage could be a good option too.

Sweet potatoes that are properly cured will keep for several months, we have had them 6 months later when we are planting out our new slips again! Go through them every month or so to check for rot so the bad potatoes can be pulled out and put into the compost.

Tips For Avoiding Disease

There are many diseases/pests that can plague gardeners, especially when growing without any chemicals. One way to avoid disease with sweet potatoes is to carefully inspect your seed potatoes. Choose ones that are completely blemish free and as close to perfect looking as possible. Also, I always practice crop rotation which means I try and avoid growing the same crop, or even the same crop family, in the same place for 3 to 5 years. The reason for this is so that any soil diseases or pests can dissipate, whereas if the same crop is grown year after year in the one spot the problems will proliferate. Sometimes the issue is a soil pH problem. This can be complicated and is beyond the scope of this post, but most issues can be solved by adding organic material to your garden soil. Leaves and compost work well. In very acid soil lime may be required. Sweet potatoes prefer sandy loose soil so when growing in very clay soil make sure to amend heavily with compost or consider growing in raised beds. If growing in the ground in clay soil, try hilling them a little so there will be increased drainage. If any of the sweet potatoes from your harvest show signs of damage from disease or bugs, store them separately and use them first to keep the disease from spreading or the bugs from getting into the rest of your potatoes. Often times the damaged parts can simply be removed and the rest of the potato can still be eaten.

Enjoying

Baking sweet potatoes is one of the easiest ways to prepare them, 375 degrees for about an hour does the trick for a medium size potato. Letting them cool for twenty minutes or so before eating them will bring out the natural sweetness. Sweet potato breakfast custard is another one of our favorites.