Growing, Planting and Harvesting Sweet Potatoes

Home of Ontario Sweet Potatoes & Round Plains Plantation Bakery

Growing Sweet Potatoes

Is there anything that tastes better than maybe SWEET POTATO FRENCH FRIES or maybe SWEET POTATO PIE.
First we must grow them!  Sweet potatoes and yams are not the same, contrary to advertisements in your grocery flyer.
Yams are grown in hot temperature areas, not in the United States or Canada.  Sweet potatoes are a relative of the Morning Glory flower plant, they can have similar flowers  and vines.  Sweet Potatoes are grown throughout the U.S. if the soil conditions are appropriate. In Canada former tobacco land in southern Ontario is the location of most of the crop.
There are between 1000 and 2000 acres grown annually with the balance imported from the United States.  There is a current consumption of at least 10,000 acres in Canada and this is growing every year.

What is involved in growing sweet potatoes?

  1. 1. Soil must be a loose sand type.  The tuber can grow to 2 liters/quarts or more in size. If the growth tuber is restricted by the soil it will be compromised.
  2. 2. Growing season in June to late September or early October, at least 100 frost free days.
  3. 3. The hotter the temperature the better.
  4. 4. Moisture is not critical, they like the hot weather and are drought tolerant after they are initially established.
  5. 5. They will not grow well in marsh soil if there is a cool water sub soil base.
  6. 6. There are no sprays available to control weeds, a hoe is essential to control weeds.

Sweet Potatoes are grown from "slips" which are harvested from tubers planted in green houses in Canada or fields in the warm states.  They are not grown from "eyes" like table potatoes.  The source for most "slips" is South Carolina which are packed in 1000 slips to the box for approximately $70/box available for pickup the first week of June from Round Plain Plantation and Ontario Sweet Potatoes in the Waterford area.  It takes about 14 boxes to the acre.
There are several varieties (4500 varieties grown around the world), Beauregard for years has been considered to be best suited to Ontario because of its shorter growing season. A new variety, Covington appears to be another variety to be considered... The Beauregard variety produces large tubers which grow horizontal and vertical. Covington grows more vertically with more medium size tubers with a lovely taste.


  1. 1. The slips are from 15cm /6 inches to 30 cm/12 inches long.  They do have leaves but do not have roots or any part of the host sweet potato attached.  Disease carries in the root and no soil is present as it not allowed to be carried across borders.
  2. 2. Establish straight rows a little more than a metre or yard wide.  This allows tractor cultivation.
  3. 3. Slips are plants 30 cm/1 foot apart in the rows.
  4. 4. The slips are inserted into the soil 5 cm/ 2 inches or more with 2 leaf nodes covered with soil.  The plant roots and the tubers will grow from the nodes.
  5. 5 .If the soil is moist at the time of planting, a water supplement is not required.
  6. 6. The slips will wilt for a week or so then come back to life.
  7. 7. In about a month a small bush will develop with a few short runners.
  8. 8. Time to get the hoe ready to attack the weeds is required.
  9. 9. In about another month the runners will get fully established with a mass of vines making weed control difficult until harvest.  The vine canopy will assist in weed control.

Harvesting Sweet Potatoes

  1. 1. Before the first frost, get out the lawn mower to chop the vines, it is impossible to harvest with the vines in place.
  2. 2. After the vines have dried or been removed start harvesting.
  3. 3. If the quantity to be harvested is significant, a sweet potato digger may be required (Willsie Equipment, Thedford). For a small quantity a shovel and strong back will do the job.
  4. 4. Tubers can be 20cm/8 inches long with points at both ends, 10 cm/4 inches in diameter.  Be careful not to damage or break off the points.
  5. 5. With the vines removed it is difficult to locate the tubers in the ground, thus the need for straight rows.  The tubers develop horizontally and vertically thus the width of the tuber growing area can be quite wide (50cm/15 inches) and deep (30 cm/12 inches).
  6. 6. Tubers in the ground have very tender skin, exposure to heat and sun for a day or two will toughen up the skin for less damage.  Digging and placing the tubers in containers can result in damage to the tuber if not done carefully.  Damaged tubers should be left in the field unless processing facilities are available.  (Sweet potatoes are used for pet food).
  7. 7. Having dug the tubers and carefully placing in moveable containers, the next step is converting the starch of the tuber to sugar.  This is done by storing the tubers in a heated area at 30 degrees C or 85 degrees F with 85% humidity with good air circulation for 10 to 14 days.
  8. 8. For small quantities cover the boxes with tarp and blankets to retain the heat, using a vaporizer to add water and an electric heater to add heat.  Use your outdoor temperature sensor to monitor the temperature and humidity within your little igloo, make adjustments as required.
  9. 9. The tubers are now ready to be enjoyed.
  10. 10. Tubers should be stored at 15 degrees C or 60 F with 50% humidity.  They will keep over a year in suitable conditions.
  11. 11. For small quantities boxes covered with a blanket placed along and exterior wall in the basement works well.
  12. 12. Yield should be about .5 k/1 lb of tuber per slip.  It looks like and sounds like a lot of manual work, that's why the price in the produce department is much higher than "white, yellow, red, green, blue, black" table potatoes.

Living the sweet life article in Brantford Expositor
TheSpec com - food - Sweet perfection
Giving thanks for sweet potatoes