The Fastest Surefire Way to Start Sweet Potato Slips For Planting

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If you are concerned about personal food security, here is a garden-to-table, sustainable, nutritious, and fun springtime project and a great way to prepare to grow sweet potatoes in your container garden, raised bed, or directly into non-clay ground where the soil has been well-worked.

It’s easy and cheap! And unlike most garden vegetables, sweet potatoes aren’t grown from seeds.

Some of you may remember when you were back in grade school and would try to sprout a promising-looking sweet potato with toothpicks in a jar of water to make a cool house plant.

You might have produced a robust, green vining plant OR the result may have been a rotting mess of sweet potato. To know which end should go up in your glass of water, simply place the tuber in a warm place for 1-2 weeks (I just set them behind my kitchen sink), and let the buds emerge. That end goes up!

But there is a faster, more successful, way!

The Fastest Surefire Way to Start Sweet Potato Slips

Sweet potato slips can be started in two ways, in water or in dirt. Of course, both propagation methods work, but starting a slip from a sweet potato in dirt is the more rapid method.

Set several small or medium whole sweet potato tubers on their sides, half exposed, in peat moss or potting soil in a plastic or aluminum pan with a few drain holes and a catch plate.

Keep the bed evenly moist (but not soggy), and in a few weeks shoots will emerge to grow upwards. Put it in a warm, sunny window or under a Grow-Lamp. (See 2 minute video below).

Slips will be abundant in four to six weeks, and abundance is what you want:

(Source for image on left)

The slips take about a total of eight weeks to mature, so you should be starting sweet potato slips about six weeks before your LAST frost date in the spring.

The timing is important if you want to grow large, tasty sweet potatoes. This plant loves warm weather and should be planted only when the soil reaches a consistent 65 degrees F. (18 C.).

Included in that time, slips grown indoors need to be gradually exposed to strong summer sun over a period of 1-2 weeks. This is easily accomplished by placing the mother plants in warm filtered shade out of strong winds.

But wait. Aren’t sweet potatoes a tropical crop, difficult to grow in cool climates? Barbara Pleasant says, “Yes and no. In recent field trials in chilly New Hampshire, for example, fast-maturing varieties like ‘Beauregard‘ and ‘Covington‘ produced three to four nice tubers per plant when planted into black plastic mulch, which helps warm the soil. Still, you will get a bigger harvest when growing sweet potatoes in a warm climate than a cool one. In warmer climates, gardeners sometimes harvest eight or more tubers per sweet potato plant. (source)

Gathering and Rooting Slips:

Take the slips from the main sweet potato root by twisting them while tugging on the slip.

Once you have the slips in hand, place them in a glass or jar of water for about two weeks.

And when the roots look strong and your soil is 65 degrees, they are ready to plant. It doesn’t take long.

Planting Outside:

If you have several large container(s) (like 55 gallon blue drums, hacksawed in half), that will work, but they need 3-4 drain holes drilled.

Where the vines touch the soil, they will set roots, and you may or may not want that. I don’t let this happen in my pretty stone garden paths.

Years ago, my sweet husband and our sons made raised 4’x8′ garden boxes for us, so it will be easier for us to harvest.

My Potager Kitchen Garden. The 4’x8′ boxes are filled with loose soil, peat moss and vermiculite. Here is the exact recipe.

Sweet Potato Tips:

Feeding – Mix a very light application of a balanced organic fertilizer (12-12-12) into the soil before planting. Too much and there will be small potatoes and excessive vines.

Spacing – 18” (45cm) each way (minimum)

Harvesting – Potatoes are usually ready as the ends of vines begin to turn yellow or just before frost. Harvest before frost as cool temperatures can reduce tuber quality and storage. To harvest, find the primary crown of the plant you want to dig, and use a digging fork to loosen an 18-inch wide circle around the plant. Pull up the crown and use your hands to gather sweet potatoes. Cut vines out of your way before digging. Cure tubers to develop sweetness by lightly brushing off soil, laying unwashed tubers in a warm (80°F to 90°F), well-ventilated place for about 10 days.

Storage – Store sweet potatoes in a cool, dry spot. Do not refrigerate or store below 50°F. Cured sweet potatoes can keep up to 4-6 months when stored around 60°F with high humidity. A basement is ideal, though a cool storage room works, too.

Troubleshooting – Deer are fond of sweet potato vines.

2 minute visual recap: