Why Dig Your Own?
Digging for sweetpotatoes is like opening a box of assorted chocolates. You never really know what you’ll find until the digging is underway. Each year, harvest time continues to amaze me! Unlike fruits and vegetables that grow above ground, with sweetpotatoes, all you can see is the vine growth (and occasional blossoms). That’s part of the attraction. It’s the expectation, the anticipation of what’s there. How many good size bakers will be in each hill? Will the sweetpotato roots be uniform in shape and size? Will I get one over 3 pounds? Will there be an unusually shaped one this year? You just never know about the harvest, until you dare to dig.
Unlike other crops where the harvest date is critical for picking the best produce a delayed harvest will generally result in larger roots. Size does not seem to negatively affect the flavor of the Ipomoea batatus, the scientific name for the sweetpotato.
When the soil is dark and rich, the contrasting color of the expansion roots (which can be red, burgundy, orange, purple or cream colored) is a sight to behold. I put that tiny slip (a plant not bigger than a seedling) in the ground just three months ago! Now, 90 to 100 days later I have a 2-3+ pound yield per plant. It’s nothing short of miraculous!
There is no real nutritional advantage to digging your own sweetpotatoes. You will, however, have the personal satisfaction that what you have dug up is very fresh. If, however, you just can’t wait to taste the freshly dug sweetpotatoes, you may be slightly disappointed in the immediate garden-to-table taste. Give it time. The freshness does not yeild sweetest. Sweetness takes time In fact, it usually takes several weeks after the curing process for the enzymes to release most of the sweetness for which sweetpotatoes are known. Be patient. The best is yet to come.
To Wash or Not to Wash?
Some farmers will tell you not to wash newly dug sweetpotatoes right after harvest because unwashed sweetpotatoes will keep better/longer. Even so, I gently rinse them off with a garden hose and they have kept nicely for 10+ months after curing. After harvest, wash your sweetpotato roots. Lay out your harvest in a convenient spot in the garden and gently hose them off without scrubbing or bruising. (Rinsing keeps all the mud and mess outside and allows you to inspect each root before arranging them for curing.)
Curing. Harvest Day Is Curing Day – start within hours of digging
If you want the full flavor of the sweetpotato (and why settle for anything less?!), then curing is a must. Curing seals in the moisture, heals injuries and activates the enzymes which convert the starch to malt sugar, thereby sweetening the flavor. This process involves activation of “suberin” – a waxy substance that is like an organic “plastic baggy” which helps retain moisture and heal harvest wounds. Without curing the sweetpotato will shrivel up from moisture loss and rot.
Curing Rule of Thumb: The warmer the curing temperature, the shorter the cure.
Longer Method: An Easy and Simple Sweetpotato Curing Method. Put your sweetpotato roots in doubled paper bags in the warm (75+ degrees), moist (75% humidity) area of the house. The bathroom?) Leave them there for 3 to 4 weeks.
Shorter Method: Ideal curing takes 5 to 7 days at 85 to 90 degrees and 80 to 90% humidity. If the temperature drops even 5 to 10 degrees, curing time doubles.
If you have a gas oven with a pilot light, put the sweetpotatoes in a paper bag and keep the oven door slightly open. Temperatures are usually right around 90 degrees.
Remember the goal of curing: to activating the enzymes, to sweeten the potato, and to seal in its natural moisture. How can you keep the temperature at 85 degrees and prevent moisture loss? Create a mini controlled environment with heat source. Build a pup tent out of tarps/blankets. If needed, use a small space heater with a thermostat and a method to achieve moisture containment (double paper bags (loose folded over) in a cardboard box. This will allow for “breathing” of the sweetpotatoes and curing gases to escape) This process will prevent moisture loss from the sweetpotato, stabilizing storage for 6 to8 months following the curing procedure.
For larger quantities, I’ve used a boiler room with a small humidifier. I drape the containers with loose plastic coverings (with small breathing holes for gas/air exchanges). Spare bathrooms will also work, particularly those with room thermostats. (Use an oil-filled electric “radiator” heater. They work very nicely and most models have a thermostat.) Turn up the heat to 85° for 7 days. Occasionally turn on the shower to produce steam bath effect. You might need to be creative. Use a small self-standing, camping tent in the house with an oil-filled electric heater inside. Most camping tents will hold the heat and moisture while allowing “breathing” -- an escape of the by-product gas from the suberin production. Allow for adequate ventilation.
Storage of Sweetpotatoes After Curing.
Keep the cured sweetpotatoes between 55 and 68 degrees for the best long-term storage. Temperatures lower than 55 degrees will trigger the cold chill injury factor – (hard-core centers in the sweetpotato no matter how long you bake them). Higher room temperatures will promote sprouts … depleting moisture and draining nutrients. Usually a spare bedroom – with the thermostat adjusted to 58-60 degrees. Keep the roots inside paper bags inside cardboard boxes (waxed boxes, if you can find them). It is possible to successfully keep roots for over 10-12 months with only minimal deterioration of quality.
Experiment with creative uses of this most wonderful delicious/nutritious blessing from the garden. Sweet potatoes are a nutritional natural; eat them twice weekly. Blessings to you!
Jack D. Osman, Ph.D. Additional information on sweetpotatoes is available at:
Stewartstown, PA 17363 © Jack D. Osman, 2011