If the potatoes are still firm and the skin is not green, yes, then you may certainly eat them. When you harvest them, inspect them for diseased looking tubers. If the potatoes appear fine, then yes, you can also use them to start new potatoes. Though it is recommended to plant certified disease free tubers.
After the greenery has died back, potatoes can stay in the ground for several days, if the conditions are right. As long as the soil is dry, and the temperature is above freezing, you don't have to harvest potatoes immediately. But it is best to dig them up within a few days to prevent rotting.
What happens if you don't harvest potatoes? You'll create a perennial potato patch! Depending on your climate, the potatoes left in the ground will either sprout soon and grow new plants or will overwinter and sprout new plants next spring.
After harvesting, potatoes must be cured. Let them sit in temperatures of 45 to 60 degrees Fahrenheit for about two weeks. This will give the skins time to harden and minor injuries to seal.
Generally speaking, storing potatoes in the ground is not the most recommended method, especially for any long term storage. Leaving the tubers in the ground under a heavy layer of dirt that may eventually become wet will most certainly create conditions that will either rot the potato or encourage sprouting.
However, be sure you allow the cut potatoes to cure prior to planting. If you don't, they'll rot in the ground.
The flowers and foliage determine when to best harvest your crop. Harvest baby potatoes (new potatoes) two to three weeks after they've finished flowering, and harvest potatoes for storing (mature potatoes) two to three weeks after the plant's foliage has died back.
Before curing potatoes, I lightly rinse them in cool running water to remove excess soil, but I make no attempt to remove soil from eyes and crevices. Serious scrubbing should always be delayed until just before the potatoes are cooked.
Truly new potatoes are sold right after harvest, without any curing. They're higher in moisture so have a little bit different texture, and their flavor has, to my taste, a slight bitterness that complements the earthy flavor.
Mature potatoes should be cured before eating. Curing causes the skins of potatoes to thicken and slows the respiratory rate of the tubers, preparing them for storage.
Cure potatoes at a temperature of 45 to 60 degrees Fahrenheit and high relative humidity (85 to 95 percent) for two weeks. Healing of minor cuts and bruises and thickening of the skin occurs during the curing process. Once cured, sort through the potatoes and discard any soft, shriveled, or blemished tubers.
On that somber note: To scrub potatoes, rinse them under cool water then brush them with a vegetable brush if you want to be extra thorough. You can skip the brushing if you like; sometimes I use a nubby kitchen towel to scrub and dry all in one step.
Boil New Potatoes:
Place the potatoes in a medium saucepan and just cover them with salted water. Bring the water to a boil, cover, then lower the heat and simmer until the potatoes are tender when poked with a fork, about 20 to 30 minutes. Make sure the potatoes do not stick. Drain the potatoes dry in a colander.
Harvesting potatoes: the right time
Early potatoes can be harvested as early as mid-June and second earlies take a few more weeks to mature, being ready to dig up around July and August. Harvesting of maincrop potatoes usually takes place later, from late August to October.
The Food and Drug Administration advises you wash potatoes before you eat them. Potatoes grow in the ground, and carry not only dirt but also bacteria to the grocery store and later, your table. Pesticides also remain on potato skin; even organic potatoes carry some degree of contaminants.
Dig potatoes too early, and you'll harvest a measly crop of minuscule tubers. You'll also risk stressing the plant and its precious root system, so although you could try replanting it, the plant might not thrive. Wait too long, and your potatoes may get damaged by frost, or begin to sprout, crack or rot underground.
Nestle your spuds into ventilated bins, bushel baskets, a Root Storage Bin or a cardboard box with perforated sides. Completely cover the boxes or baskets with newspaper or cardboard to eliminate any light. Even a little light will cause potatoes to turn green and be rendered inedible.
A year after your potato harvest, plant low-yielding, leafy vegetables, such as lettuce, radish (Raphanus sativus), pea (Pisum sativum) and spinach. Followed by green manure the year after, which will replenish organic matter in the soil and rebuild humus.
The health risks of eating spoiled potatoes
Cooked potatoes carry a high risk of food poisoning. After a few days, they may begin to harbor pathogens and bacteria that could result in illnesses, such as salmonella, listeria, botulism, and staphylococcal food poisoning.
Contaminants. Finally, because raw potatoes have not been cooked, they may contain bacteria and other contaminants that could lead to foodborne illness and infection. Any time you're eating raw foods, it's important to wash them thoroughly to remove as many contaminants as possible.
When do you wash potatoes before cooking? It's best to wash potatoes just before you use them, says the Idaho Potato Commission. Waiting to clean your potatoes is essential because they can collect bacteria after washing, says Livestrong. Leaving washed potatoes out provides ample opportunities to get them dirty again.
Raw potatoes contain solanine and lectins, two compounds that can cause gastric distress and potentially make you sick. Additionally, raw potatoes contain resistant starch, which is difficult to digest, and their overall taste and texture is nothing like the potatoes you know and love. When in doubt, cook that potato.
As you plan this year's vegetable garden, include a few slightly off-beat veggies among your tomatoes and potatoes, and they'll reward your efforts by providing fresh food next year without the work of replanting. Each of these veggies (yes, rhubarb is a vegetable!) will come back on their own.
Do not plant potatoes in the same place every year because diseases will build up in the soil. Potatoes in the home garden are often planted too deep.