Curing sweet potatoes
May 13, 2017 9:09 PM   Subscribe

I am about to dig up my sweet potatoes. Going by last year's harvest, I'm expecting I might have a couple of hundred large ones. The internet tells me I should cure them for 1-3 weeks in a place with high humidity and temperatures of 18-30 C (65-85 F). I'm not sure exactly how to do this without spending more money than my potatoes are worth! Any clever ideas?

Last year I didn't know to cure them before storage, and they were okay, but not that sweet, and they didn't last very long before rotting. This year I'm thinking I'm going to give a lot away, and make a lot of freezable things too, so I'm not so worried about rotting, but I'd like to maximise sweetness.

The temperatures at the moment in the house are around 22C during the day and fall to around 12C some nights. The daytime temperatures are fine, but the night time ones not so much. We have central heating, but haven't started using it yet, and I'd rather not. Also, to get high humidity, I was thinking I'd put the potatoes in the laundry/bathroom, but that's one area of the house that doesn't have heating.

We have a garage, but it's unheated, and has a problem with cockroaches and spiders. I'd worry about leaving the potatoes down there because of the insects even if the temperatures are okay.

The internet recommends a covered porch (do not have), a sunny backyard (temperatures too low at night), or building a little greenhouse-like structure, or something complicated with crates and straw and a roof, none of which we have the building materials for, and which are going to work out to cost more than the potatoes are worth.

We also don't own a space heater. (Some sites recommend putting one in a bathroom and leaving the potatoes in there).

We also don't have any crates, racks or even any newspaper, which most sites think the potatoes should be spread out on. (I'm happy to buy newspaper, but not so much crates or racks for a few hundred potatoes).

Given all these constraints, is there any clever way to cure the potatoes? Will they be fine anyway if I leave them on the laundry floor in these conditions for a few weeks?
posted by lollusc to Home & Garden (8 answers total) 3 users marked this as a favorite
Could you staple them inside sheets of scrap cardboard and affix flat bundles of them to the surface of your water heater tank?

Assuming you have a water heater and its tank's surface is in the correct temperature range and it's not covered in fiberglass insulation or something like that.

(I have no potato-specific knowledge.)
posted by XMLicious at 10:44 PM on May 13, 2017

You could make a small cheap greenhouse with some shipping pallets and some Visqueen (polyethylene sheeting). A quick search shows some free ones available in your area on a site called gumtree. You may want to borrow some for a store so you will not have to store them or dispose of them when you are done. You probably want a minimum of 4 for bottom and three sides, but could use 6 to make a full cube or 5 to have one side open. You probably want to Visqueen the top and sides but leave the bottom open as you should get some heat out of the ground. You could put some earth from your garden around the base to help hold the heat in. The pallet on bottom will allow air to circulate.

If your clothes dryer vents out the side you could try to direct this into your greenhouse as this will put to use hot humid air that would go to waste. Do your laundry at night. You could put blankets on top at night to keep more heat in.

If you have a friend/neighbor with a space heater, you could barter the use of it for a few weeks for some sweet potatoes.

Keep in mind you are looking for a chemical reaction to happen, converting the starches to sugar. With higher temperature and humidity the reaction will happen more quickly, bit will still happen if you are at the lower limits, it will just take longer. And I am not an expert, but I assume if the temperature drops below the limits of the reaction, it will pause until it raises enough to resume, taking even longer.
posted by Yorrick at 10:59 PM on May 13, 2017 [3 favorites]

Good ideas. I don't have a clothes dryer, and my water heater is outside and therefore extremely well insulated, so I think that won't work either.

The small make-shift greenhouse idea is a great one. Unfortunately because I was overly enthusiastic I went and dug up the potatoes in the last couple of hours since I posted this question, and now it's Sunday night and I won't have time for gumtree sourcing of materials again until next weekend.

I have put them in a wheelbarrow for now. I'm actually wondering if that can be the basis of my storage system. It doesn't let air circulate from below or the sides, but I could probably rig up a towel over the top with some gaps for ventilation, maybe. They are all piled on top of each other, though, not spread out in a single layer. Is that okay?
posted by lollusc at 12:09 AM on May 14, 2017

Fwiw space heaters are quite cheap (though running them for so long might not be).

How insulated is your kitchen? Do you cook a lot? If it's fairly insulated cooking at night might keep it warm enough. Is it possible to keep things next to the side (or even back) of your fridge?
posted by trig at 1:14 AM on May 14, 2017

Cover the wheel barrow with garbage bags or glad wrap for now; it will make a decent albeit not greet green house. An old blanket or towels on the bottom might help, too.
posted by smoke at 4:37 AM on May 14, 2017

Where were you planning on storing them after curing? If you can just air dry the skins for 7 days or so they should be fine for a few months without any other treatment. I would leave them out in the yard in the shade under a tarp for a week. Slightly lower overnight temps aren't going to ruin them, nor is slightly lower humidity.

Here's some good info from U. Illinois in case you haven't seen it.
posted by SaltySalticid at 7:36 AM on May 14, 2017

Since your average temperature is not too far off, you might just put them in an insulated space, e.g. a picnic cooler. This assumes that it's OK to keep the closed up.
posted by SemiSalt at 10:02 AM on May 14, 2017 [1 favorite]

Sitting out in a cardboard box (protected from direct sun and rain) can do it as well.

Neighbor kept a shipping container at his plot (for tools etc), and would cure his sweet potatoes in it.

I use my open/unheated garage - laid them out on newspaper on a table for two weeks. Daytime temps were 80s/90s, night time 60s-70s, all but 2 kept over winter. Bugs/spiders left them alone, but we use our garage for car parking, etc, so it's opened all the time.
posted by k5.user at 8:31 AM on May 15, 2017

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