Mysterious, potentially dangerous squash are appearing in gardens across Maine.
These squash, which were not planted by people, often have mixed features from different species. Some are familiar shapes with mismatched colors — such as the spinning-top silhouette of an acorn squash, speckled yellow instead of its typical dark green and orange coloring — while others are misshapen tubes in unexpected shades.
These “volunteer” squash often come from seeds that didn’t break down in a compost pile, were dropped from rotten fruit the season before or were carried in by animals.
Quirks of squash biology mean that they interbreed with each other more easily than most vegetables, often producing fruit the next year that you’ve never seen in a seed catalog. They might be safe to eat, but could have a different chemical content that will make you sick.
Squash are especially likely to create mixed offspring when the female flower is pollinated with pollen from the male flower of a different variety, resulting in fruit that have qualities of both. Called “cross-pollination,” this can happen with different types of squash that are the same species.
For example, cross-pollination happens among plants within the species Cucurbita pepo, including the subspecies of zucchini, some pumpkins and squash such as acorn, spaghetti, patty pan and delicata.
In very simple terms, this means the resulting seeds can produce very different fruit the next year, and the squash that appears on its own in your backyard may look unlike anything you’ve grown before.
Should you eat a wild squash?
We buy seeds from professional breeders for a reason. Commercial varieties are bred to have less of a bitter-tasting compound called cucurbitacin, which is also found in other members of the cucurbit family such as cucumbers and zucchini.
Cucurbitacin can make you sick in high concentrations, causing stomach cramps, abdominal pain and diarrhea for up to three days.
Researchers have called this effect “cucurbit poisoning” or “toxic squash syndrome,” and two women in France reported losing clumps of hair afterward.
In much smaller amounts, these compounds may actually be good for you. Researchers have found cucurbitacins can be effective in fighting cancer, diabetes and inflammation, among other ailments.
One of the simplest rules of thumb for consuming wild foods applies here: don’t eat it if it makes you gag. Even if the squash just tastes bitter, spit it out and don’t eat the rest.
If you are trying to save squash seeds yourself, you can minimize the possibility of cross-pollination by covering the beds to keep out pollinators or taping the flowers shut when they begin to form until you’re ready to pollinate the plants by hand.
