COLUMN: Curing root crops essential for storage

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By Jeneen Wiche

Potatoes, garlic and onions: these three vegetables are staples worldwide partly because of their versatility and partly because of their storage-ability.
Late July and August are when our spring planted onions, garlic and potatoes reach maturity and are ready for harvest. If you want to harvest some new potatoes, onions or garlic before they reach maturity, enjoy them at the table in short order, but if you want to store them, it is important to harvest them at the correct time.
Check your seed packet or variety information for details about how many days are expected for maturity. Some varieties may be later.
Garlic is the easiest in my experience. Wait for the tops to die back by about 50 percent. I used to wait until they were completely brown, but have altered my plan a bit after reading what other garlic growers do. The longer a crop is in the ground, the more that can go wrong, right? So, as soon has the cloves have formed (which is usually by summer solstice) and the tops begin to brown noticeably, the garlic comes out of the ground. This year the harvest was nearly perfect.
To cure the garlic for storage, leave the garlic and stalk intact and lay them over a screen, or some similar device, for one to two weeks in a shaded, well-ventilated location. Once the bulbs feel dry, braid them all together or cut the stems ,leaving a couple of inches above the bulb and store in a mesh bag. A cool, dark storage space with good ventilation is ideal.
The signal that your onions are ready for harvest can be seen above the soil, as well. The tops of the plants will begin to flop over and die back. Once about half of the tops have turned brown and flopped over, the onions are at their peak for harvesting.
You don’t want to harvest too early, because the bulb size will be small, and they will cure slowly and be more likely to decay before you use them. Putting off harvest too long also increases the chances of decay.
Once the tops flop and have died out, get digging. During the curing process, you want to cut the tops back to about 2 inches and lay them out on a screen in that same dry, well-ventilated, shaded place your garlic enjoyed for about two weeks. As they cure, the necks shrink up and phenolic compounds accumulate there, which helps to stop rot.
Those onions with thicker necks have a harder time protecting themselves from rot, so go ahead and sort those out and use them first. Those that look clean can have the remaining tops snipped after two weeks of curing. Onions are most successfully stored at 32 degrees with a low humidity level. Rot and sprouting during the bulb’s dormant period are more prevalent when they are stored at temperatures above 40.
Other ways to increase your onion harvest and successful storage is to start with the right variety at planting time. In Kentuckiana we should plant intermediate, day-length onions (these onions set bulbs when day-length averages 12-14 hours) including the Super Star, Candy, Ebenezer, Stuttgarter, Spartan Sleeper, Storage King, Sterling and Big Daddy varieties.
Interestingly, the more pungent the onion the better it stores because of higher levels of the phenolic compound, which helps to keep disease down in the bulb.
Potatoes, depending on the variety, can be harvested early, mid or late season taking as little as 70 days to maturity up to 135 days. For storage, wait until the tops have completely died back. I typically wait another week or two after this before digging so that the skin has a chance to harden off. If you do not do this, then be sure to let them cure in the shade once dug.
Sort your potatoes and keep the bruised or cut ones for eating now; set the clean ones aside so they can cure for one to two weeks at 65-70 degrees and high relative humidity.
Be sure to keep them out of the sun. Sun exposure causes the potato to turn green. Once they are cured they are ready to be stored in a cool, moist, dark place that maintains a temperature between 40-50 degrees.
Better not to store them in refrigerator, the cold turns the starch to sugar.