When the plants die, it's time to harvest that potato crop
Vegetable gardeners know that the arrival of August is often also the arrival of potato-harvesting season. If you're new to growing potatoes, you may find it challenging to know when it's time to dig them up, but there are some sure signs to watch for that will tell you precisely when it's time to pull the digging fork out of the shed.
As soon as potato plants come into flower, you know they've reached maturity and have begun to form their below-ground tubers. The plants will continue to grow and flower for several months, and eventually, they'll naturally begin to die back.
Mature potatoes are ready to dig just a few weeks after the plants have completely died. At first, just the lower leaves will yellow, but soon enough the entire plant will turn brown and flop to the ground. After this happens, wait two more weeks before digging up the tubers.
By leaving the potatoes in the ground for those extra two weeks, their skin thickens and cures, improving their shelf-life and cutting down on post-harvest disease issues.
When harvesting time arrives, choose a dry day and use a digging fork or pitchfork, or a three- or four-pronged potato hoe, to gently pry up each plant. Work around the outside of the plant, starting a foot or so from its base and working your way inward so you don't accidentally spear any tubers. Be sure to insert the fork down underneath the plant and gently pry in an upward direction to lift each plant up out of the soil. As you unearth each potato, pick it up and dig around in the loosened soil for more nearby spuds.
If you happen to accidentally damage any of the potatoes, use them within a few days. Do not store them with undamaged tubers because any rot that may develop can quickly spread.
Once your harvest is complete, brush the potatoes off with your hands, gently removing any excess soil. Do not bruise or break the skin, and do not wash them before storing.
Spread the dug potatoes in a single layer in a well-ventilated, dry garage or basement, and let them rest for three or four days.
Store homegrown, fully cured potatoes in cold, dark conditions. The ideal temperature is between 45 and 55 degrees F. Don't put them where they'll freeze or store them in the fridge. Protect the tubers from light to keep them from turning green.
It's also possible to save some of your potatoes for next year's plantings. After harvesting, separate the smallest tubers and store them in a completely dark box or bin, wrapped in layers of newspaper. Put the box or bin in a cold garage but do not allow it to freeze. They may be shriveled or sprouted by the time planting-time arrives next spring, but the tubers can still be used.
Be aware, however, that saving your own tubers for replanting may increase your chances of developing a disease in subsequent seasons. Pathogens can easily overwinter on the potatoes and be reintroduced to the garden upon planting.
Horticulturist Jessica Walliser co-hosts “The Organic Gardeners” at 7 a.m. Sundays on KDKA Radio with Doug Oster. She is the author of several gardening books, including “Attracting Beneficial Bugs to Your Garden: A Natural Approach to Pest Control” and “Good Bug, Bad Bug.” Her website is jessicawalliser.com.
Send your gardening or landscaping questions to firstname.lastname@example.org or The Good Earth, 622 Cabin Hill Drive, Greensburg, PA 15601.