Maine Gardener: The thing about gardening? There are always surprises

They may look like unripe cherry tomatoes, but they are actually the fruit of the potato plant. Don’t eat them! They are poisonous. Photo by Tom Atwell

While “stealing” some new potatoes for dinner a few weeks ago, I was surprised to see berries growing on some potato plants.

I say berries, but they looked more like cherry tomatoes that hadn’t ripened yet. The fruit appeared on only one variety, ‘Rose Gold’, which we purchased a few years ago from Wood Prairie Farm in Aroostook County. Since then, we keep some of them as seed potatoes.

That potato berries look like green cherry tomatoes is not surprising as the two are related. Both belong to the nightshade family, also called nightshades. Potatoes produce flowers every year – Fort Fairfield in Aroostook County even has its Maine Potato Blossom Festival every July. But while the mostly yellow flowers of tomatoes regularly produce fruit, the white to pink flowers of potatoes rarely do.

A Michigan State University Cooperative Extension article explained the puzzle. Potatoes only fruit during cool growing seasons. In southern Maine, the start of summer was cool (although too dry).

Potato berries are inedible; in fact, they are poisonous. They contain solanine, which probably wouldn’t kill you but would make you sick. Solanine is also formed in potatoes which are left in the sun and turn green.

After discovering these potato fruits, what to do with them? My first reaction was to cut them. Berries could steal energy from underground tubers, the reason we grow potatoes in the first place. My second reaction was, heck, let them grow. I’m curious. I want to see what happens.

Curiosity took over. Fortunately, I was reassured by reading further the article on the extension. Leaving the fruit alone, I learned, will not stunt the growth of the tubers. When ripe, the berries sometimes turn purple and fall to the ground. They also produce seeds which, if left to grow for several years, would produce potatoes.

Such plants would not be the same as the “Rose Gold” potatoes that produced the fruit. To breed a variety, you need to plant the eyes of preserved potatoes. Likewise, no new potato grown from the seed of the berries would be identical to either parent. In practice, hybridizers are the only ones likely to plant the seeds of these potato berries. They would do this in hopes of developing a unique colorful or flavorful potato to capture the market.

Some readers might wonder why I was harvesting potatoes in late June and early July instead of September and October. I love new potatoes. I eat them barely cooked, soft and tender, with butter and pepper. They don’t even need salt. New potatoes are the reason I grow potatoes; harvest them using a trowel to carefully remove soil from the roots of the plant to reveal the tender little potatoes. Cultivating ours wouldn’t be worth it for the kind you dig up at the end of the season. These are available at low prices in the fall, although I would miss the unusual varieties like Rose Gold, Red Thumb and Carolina. New potatoes, however, are worth it.

Another note: After reading about the process last winter, I tried grinding our potatoes before planting them this year. The process involves taking seed potatoes out of their dark storage space, cutting them up, and placing them in a warm, sunny room three or four weeks before planting them. Eyes produce small shoots early and are believed to speed up production.

It worked. We had our first new potatoes earlier than ever this year.

Tom Atwell is a freelance writer who gardens in Cape Elizabeth. He can be contacted at: [email protected]


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Terri S. Tomasini