You can’t see the potatoes growing underground, so how do you know when they’re ready to harvest?
Unlike tomatoes and radishes that you can watch grow and ripen, potatoes are buried beneath the soil, and there is no easy way to see if they are ready to harvest or not. Since we can’t see the potato, we have to look at the rest of the plant for signs that the potatoes are ready to be pulled out of the soil.
The first sign that your potato plant gives you to tell you that little potato spuds have started forming underground is flowers! When potato plants begin to bloom and develop many star-shaped flowers, you can be sure that some small potatoes grow just below the soil surface. Potato plants generally start to produce flowers around 60 days, or two months, after planting. If you’re looking to harvest small, tender baby potatoes, this is the perfect time to dig around the plant and collect some new potatoes.
If you want to grow big potatoes to store and use through the winter, you will have to wait another 4 months and look for another signal from your plant before digging up the buried treasure. After flowering, the next sign from the plant that your potatoes are ready to harvest is the yellowing of leaves and the slow dying-back of the plant. The potatoes are the storage organ of the plant, so if the plant is still flourishing, there is still starch to be stored in the potatoes. When the weather starts to cool down in fall, and the plants can no longer keep a steady flow of food moving to the potatoes, the plants begin to die back, and the potatoes start to prepare themselves for the winter.
Once the plants have died, you can chop off the greens and leave the potatoes in the soil for another week or two. Leaving the potatoes in the soil gives them time to develop tough outer skin—a process called curing. Allowing your potatoes to cure is essential if you plan to store them throughout the winter. The tougher skin protects the potatoes from damage, which is critical as damaged potatoes can rot in storage.
If you grow potatoes in an area that experiences wet winters, you can harvest them when you cut the vine and cure them in a cool, dry place for two weeks before storing them. Take care when harvesting your potatoes before allowing them to cure, as the skins are still soft, and it is easy to cause damage.
Harvesting potatoes is like nature’s own treasure hunt!