Sweet potato harvest

Harvested some Vardaman and Nancy Hall sweet potatoes today.

Good size to them (even the usually smallish Nancy Hall), but about 75% are cracked, plus, no matter how careful I was, I sliced and broke a couple.

A. Why the cracks?
B. Will they still keep?


I think the cracks are from uneven watering or rain. Mine always stored fine once cured, though you will have to cut away the cracked part when you eat it.
Others may be able to offer different perspectives.


Agreed. Cracks ‘skin over’ during curing and present no problem in storage. Extreme changes in soil moisture can cause cracking. Lots of organic matter in the soil modulates the soil moisture (plus mulching) to avoid extremes.


So after a few days, dark spots are appearing. They look like scurf, except they weren’t there at harvest, and my understanding is scurf would have been present at digging.

I lightly scrubbed and rinsed off the dirt…maybe I damaged the skins?


They do bruise easily before curing. Can you cut one open and see what the flesh under the discoloration looks like?

I did, and in cross-section, it looks a bit “off” about a millimeter deep or so.

If I bruised them, and ruined their ability to keep, I’ll be all kinds of pissed off.

My only option, I guess, would be to cook them now, sweeten if needed, and mash them, since you can freeze frozen mashed sweet potatoes with reasonable success.

There is a method I read about to “force” the conversion of starch to sugar, to hold them at 140 - 170 degrees for several hours. I’m not sure how to do that, except maybe in the “warm” setting in the oven, or put a very large pot of water on a small burner on low.

What do you think? Might they end up curing OK?

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I cook mine within a week of harvest.

I very lightly brush the dirt off and store them dirty. I still have a few of last years in the pantry.

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I want to save them for Thanksgiving.

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From my notes.

Storing. Do not wash – some dirt on skin is good, just remove excess dirt by lightly brushing. Cure sweet potatoes by holding them for about 10 days at 80-85°F and high relative humidity (85-90 percent). If the warmest temp is lower, say between 65-75°F, the curing period should last 2-3 weeks. To maintain the required high humidity (85-90 percent relative humidity), stack storage crates or boxes and cover them with paper or heavy cloth. Packing in perforated plastic bags will also keep humidity high, yet the perforations will allow excess moisture to escape. During curing process the skins thicken, the cuts heal over and the starches turn to sugars. Curing is complete when rubbing 2 potatoes together does not damage skin. Once the sweet potatoes are cured, move them to a dark location where a temperature of about 55-60°F can be maintained during storage. Place them in open plastic grocery bags so they don’t dry out over the winter. Sweet potatoes are subject to chilling injury, so keep them out of the refrigerator. Outdoor pits are not recommended for storage because the dampness encourages decay.

Those instructions are for market gardeners. I just brush off the dirt and place them on a horizontal rack I made from 1/2" hardware cloth suspended from the garage ceiling. They stay there until temps go into the 30s, then I bring them inside. They do keep a LONG time if cured properly.


I’m hoping that the dark spots are skin scuffs and not actual bruises.


Maybe cook and freeze some, and then store the rest. That way, if they do get worse, you’ll have the frozen for Thanksgiving, but if they keep fine, you will have saved a lot of work. I’ve never been terribly careful with mine and never had enough rotting or bruising to worry about.


(Long time lurker, first time poster!)

I had a similar experience this season with Vardaman sweet potatoes, but due to staggered plantings was able to make a couple of additional observations. I planted two beds of Vardaman in late May, and a single bed about three weeks later in mid June. When I harvested the May planted beds last weekend, 95% of the of the roots had cracked. The majority of those that were not cracked were from plants located in what I would expect to be the driest part of the bed (south side next to the edge of the bed). When I harvested the June planted bed, 95% of the roots had NOT cracked.

My area received a ton of rain just around the time I believe the skins would have been hardening up for the May planted beds, and since then almost no rain (during the time the June planting would have been hardening). I think this supports what others have posted here regarding watering/rain being the culprit. Even with very good drainage conditions (20" high concrete block raised beds with 6" stone footers, amended with compost and mulched) the May planted beds still split. This leads me to believe that there’s not much you can do to prevent damage in the event of ill-timed heavy rains, other than maybe physically covering the beds.

While we’re on the topic, here are a few other observations regarding Vardaman in raised beds. Planted at 16"x13" spacing, 9 slips per 4’0 x 3’4 bed, the May beds yielded 2.0 lbs/plant. The June bed yield 1.1 lbs/plant, but was planted in a bed that received significantly less sun than the other two. The vines in the June bed were noticeably shorter than the other two and the roots themselves were thinner. The vines in the May planted beds ranged from 3’ to 5’ long, which is a very manageable size for raised beds. And lastly, and maybe most importantly, they keep well and taste great! Equal to and often better than any supermarket variety we’ve purchased.


Mine are flavorless and starchy after 4 days of curing st 85 degrees…

Mine are flavorless and starchy after 4 days of curing st 85 degrees…

I’ve actually never tried them after such a short period of curing. We usually cure for 10 days or so in less than perfect conditions, in a spare bathroom with occasional space heater and steam shower to increase the temperature/humidity. This is the third season we’ve grown and they’ve tasted excellent during the prior two. Like Graftman and JustAnne4, I just brush off the excess dirt and cure/store without washing. When handled this way, even cracked roots seem to keep.


I’d set them aside and forget about them for 3 weeks or so in order that they can convert the starch to sugars

I’ve still got them in the box where it’s warm, it’ll be a week on Thursday. A lot of them have darker spots on them.

Many of the smaller, skinnier ones are so soft I can actually bend them a little bit now.

If they were mine, I’d move them to cool room temperature for a few weeks. Mine got soft during curing a few years ago, but firmed up once stored.