When to Harvest and How to Store Potatoes

Jordan Tony Sep 23, 2021

It’s everybody’s favorite starchy staple crop. It can be found anywhere from a salad in a Syrian village to fast-food French fries in an American city, but this plant comes from humble beginnings as a slightly toxic wild mountain tuber. Potatoes were first transformed into their edible and delicious state by Tiwanaku and Incan farmers in the Andes Mountains of present-day Peru. Potatoes (Solanum tuberosum) are very closely related to tomatoes, peppers, and eggplants; in fact, if their flowers are left to mature, they will produce an inedible fruit very similar in appearance to a cross between a tomato and an eggplant.

Due to their diverse nutritional content, caloric density, and storability, potatoes are an excellent staple crop for homesteaders and subsistence gardeners. To capitalize on these qualities, it’s important to properly harvest and prepare your potatoes for storage. Once you understand the principles outlined below, you’ll be well on your way to caching your delicious crop of potatoes for the winter.

Types of Potatoes Potatoes split into three primary categories based on the number of days it takes for them to reach maturity. The aptly-named early-season, mid-season, and late-season varieties take around 65 days, 80 days, and 95 days, respectively, to reach maturity.

It’s important to know the days to maturity of the potatoes you are growing because this will clue you in to when you can start pulling some up to check their growth. Generally, you should wait until all of the green above-ground growth has wilted and turned brown before digging your potatoes for storage. However, if you want to harvest new potatoes, you can start pulling them up when the plant is still green, so long as you are in the vicinity of your days to maturity.

When to Harvest Potatoes If you plan on storing your potatoes long-term, you should allow them to reach their full maturity and form a thick skin in the ground before digging them up. You can usually assume that potatoes are fully mature and ready for harvest when the above-ground growth turns black and brown and looks completely dead. The one exception to this would be if you have a soil that holds a lot of moisture and it has been a particularly wet season. In that case, I would recommend you dig your potatoes early and eat them as new potatoes to avoid the risk of spoiling from fungal disease in waterlogged soil. New potatoes do not store well, but they are a delicious creamy treat and go well with basically any dish.

One other factor to keep in mind as your potatoes mature in the ground is exposure to sunlight. The leaves and stems of potatoes, tomatoes, eggplant, and other nightshade plants contain a natural pesticide called solanine that protects them from insect predation. Interestingly, the tubers of potatoes are free of this toxin as long as they are kept completely buried under the soil or mulch (likely thanks to the work of the Tiwanaku and Incan farmers who domesticated this plant). If the tubers become exposed to sunlight, they produce harmless chlorophyll which turns them green, as well as solanine which should not be consumed. It is not uncommon for some of your potatoes to start to push up above the soil line as they reach maturity. To remedy this and prevent solanine production, simply cover them with soil or mulch for the remainder of their growth.

How to Store Potatoes Once you dig up fully-mature potatoes, the final step is to cure them for long-term storage. You might be tempted to immediately wash the dirt off so you can view them in all their glory, but this would be a mistake. The added water from washing the dirt off can promote fungal growth and prematurely spoil your harvest.

When curing potatoes, you want to have some moisture in the air, but the outside of the potatoes should feel dry to the touch. Feel free to brush off any large chunks of soil that came up with the tubers, but otherwise you can pile your dirty potatoes in breathable containers and move them to a moist, well-ventilated area with absolutely no natural light. Depending on their size, it takes approximately one to two weeks to cure your potatoes properly. A corner of a basement with a fan circulating the air is ideal place for curing.

You can store your potatoes in the same baskets that you used to cure them or transfer them into burlap sacks or mesh bags for the winter. Depending on the variety of potatoes that you grew and the conditions they are stored in, properly cured potatoes can store anywhere from four to six months without sprouting or getting soft. If they do happen to sprout early, they are still perfectly edible but they will quickly deteriorate in that condition. Make sure to rub the eyes off and eat them soon after they sprout.

I’ll leave you with a fun potato fact. Because we regrow potatoes from tubers rather than letting them sexually reproduce and grow from seed, every potato variety is a genetic clone of all other potatoes in that variety. This means that if you are growing an old heirloom potato variety in your garden, you are technically touching the same individual plant as all of the gardeners and farmers who came before you and kept that potato in circulation. You couldn’t ask for a more tangible example of how food connects us to our history and each other.