When is the right time to dig potatoes?
Question: We have a few raised beds in our backyard. We’ve grown zucchini, tomatoes, peppers and basil for the last few years, and we planted seed potatoes in one of the beds earlier this spring. The plants are green and very big, but we aren’t sure when to dig the potatoes up. Can you tell us how long we have to wait to harvest? Thank you.
Answer: Potatoes are a terrific backyard garden crop, especially for beginner gardeners. They require very little care after planting and typically produce a good crop of spuds, as long as the soil is healthy and the plants are kept well watered.
Knowing when it’s the best time to harvest potatoes isn’t difficult. However, you may find it surprising to hear that potatoes can be dug and eaten at two different times.
First, early harvests, called “new potatoes,” can be made anytime after the plants begin to produce flowers. New potatoes have soft skin that doesn’t store well, but they have a smooth, buttery flavor and are prized in the kitchen. To harvest new potatoes, simply dig around the outside of a potato plant, being careful not to uproot the entire plant. Harvest a few new potatoes from each plant, but be sure to leave the plant intact so it will go on to produce full-sized potatoes for later harvest. New potatoes should be eaten within a few days of harvest.
For mature potato harvests, you have to wait until a few weeks after the plants fully die off to dig them up. Keeping your spuds in the ground for several weeks past dieback thickens, or cures, the skin. This extends the shelf-life of your harvest and allows you to enjoy homegrown potatoes for many months.
When the potato plants begin to turn yellow and die back, stop watering them to allow the soil to dry out a bit. It can take several weeks for the plants to completely brown and die off. Wait two more weeks before carefully digging up the potatoes with a pitchfork or shovel.
Eat any potatoes damaged by the harvesting process as quickly as possible. Brush any excess soil from the rest of the dug potatoes and set them on a table in the garage for a week or so to finish curing. Do not wash potatoes before storage.
When the potatoes are ready for storage, brush off any remaining dry soil and place your spuds in a box, basket or bin. Keep them in a cool, dark room.
To increase the production of potatoes in future plantings, hill extra soil up over the plants once or twice throughout the growing season. Hilling buries more of the stem underground, encouraging the production of more potatoes. I use a hoe to mound soil from between the rows up against the stems of the potato plants. I do this when the plants are about 8 inches tall. I keep mounding soil until the plants are nearly covered.
If you don’t have extra soil to hill up around your potatoes, you can also bury the stems under a thick layer of straw. Straw makes for easier harvesting, but if it’s not thick enough, it will allow light to reach the developing potatoes which causes them to turn green. Eating green potatoes can make you sick due to compounds found in the green pigment.
Homegrown potatoes are a fun crop that pays big rewards. Both kids and adults will love digging for “buried treasure” when the time is right.
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,” “Good Bug, Bad Bug,” and her newest title, “Container Gardening Complete.” Her website is jessicawalliser.com. Send your gardening or landscaping questions to [email protected] or The Good Earth, 622 Cabin Hill Drive, Greensburg, PA 15601.