With a bit of work and effort I got the sweet potatoes planted here last week. That is normally one of the last things to get planted in the vegetable garden, and I usually get it done sometime in late May to early June so I am pretty much on schedule. Sweet potatoes are an easy to grow crop here, and they require a fairly long growing season and warm weather. We can easily supply both of those conditions, and they usually do quite well for me.
Another thing sweet potatoes like is a well-drained and loose soil that’s slightly acidic, and not too fertile. I like to make a ridge of soil that is 8 to 10 inches high and about as wide before planting, so the edible roots can form there. Our soil is a silty loam, with good levels of nutrients (including both phosphorus and potassium) according to recent soil tests, and I never add fertilizer to the bed before or after I plant sweet potatoes. Too much nitrogen tends to make for vigorous vines but small, spindly roots. For a heavier soil, the ridge might need to be a bit higher. And if soils are lacking in nutrients then modest amounts of fertilizer may be needed.
In years past I bought slips for planting, but the last few years I have made my own slips using sweet potatoes from the previous year. If you order sweet potato slips, they will often arrive in the mail looking wilted and you might wonder if they will live. The slips are tough though, and should do just fine if kept well watered until they are established. To read about how I start my slips, you can read Starting Sweet Potatoes, while Sprouting the Sweet Potatoes has tips on how to encourage them to sprout earlier. The are several advantages to growing your own, starting with the fact they take off faster since they have a well-developed root system. They also won’t have disease problems, assuming you had no issues the year before. And another good thing is: they are free!
Based on several sources, the recommended spacing between plants is anywhere between 12 and 18 inches apart. I’ve experimented with several different spacings over the years, and I now try and set the plants somewhere between 15 and 16 inches apart in the row. I like to sit the pots down the row before I start planting to make sure there’s room for all the plants I want to grow. This year I set out 29 plants in a ridge that was about 40 feet long, which averages just over 16 inches between plants. Setting them farther apart generally results in larger roots, at least in my experience, while planting closer can result in smaller roots but possibly a bit higher total yields. This year I am growing the Murasaki, Purple, Beauregard, Korean Purple and Bonita varieties.
I set the plants a bit deeper than they were growing, firming the soil well around each plant. If you are setting out slips they should be planted 3 to 4 inches deep. Then I give them a good watering, and I’ll keep them well watered for a couple of weeks until they start to grow. I tilled up the bed the day before planting, and I was able to make a ridge and get everything planted and watered in just over an hour.
And that is the how I plant our sweet potatoes here at Happy Acres. In our garden the vines are rarely bothered by pests, but if it weren’t for the fencing they would likely be nibbled on by rabbits, groundhogs and deer. I also rotate my crops so sweet potatoes and other vegetables aren’t grown in the same place every year. Once planted, they need about an inch of water per week either from rainfall or through supplemental irrigation. In a few days I will be laying a soaker hose down the length of the bed, and mulching with cardboard to help conserve moisture and keep down the weeds.
For more information about growing sweet potatoes check out these sources: