Nightshade Family

The name nightshade conjures images of dark, hidden doings of dubious intent. And in some cases, you do have to be careful around these plants. Without them, however, there would be no pizza, lasagne, or ratatouille.

The nightshade family (Solanaceae), or tobacco family, is usually the first reason people start gardening at home. After years of tasteless, watery tomatoes, we long for the summer sweet richness of homegrown tomatoes. Welcome to the world of the nightshade family!

Tomato flowers

Nightshade plant description

Plants in the nightshade family share many common characteristics that make this group easy to recognize. These traits include:

• alternate leaves, which can be simple, lobed, or occur in groups of three, each with three leaflets (biternate)
• no latex or colored sap is produced
• pubescent, which means they are covered with tiny hairs
• flowers have 5 petals and connivent anthers (come together in a point)
• fruit is a berry
• most are perennials, grown as annuals

Eggplant flower (Earth100) CC BY-SA 3.0

​ Potato flowers (Keith Weller) Public Domain

Nightshade plants

The nightshade family includes many garden favorites, including tomatoes, bell peppers, chili peppers, eggplant, tomatillos, groundcherries, and potatoes. Tobacco is also a member fo the nightshade family, but I wouldn’t eat it! Petunias, datura, mandrake, Devil’s Apple, and belladonna (deadly nightshade) are also members of this family.

Growing nightshade plants

These plants prefer rich, damp soil, with lots of organic matter. Most of the edible nightshade plants tend to get large, so be sure to give them plenty of room. These plants can carryover certain pests and diseases, so regular crop rotation should be used. The most common diseases of nightshade plants include tobacco mosaic, verticillium wilt, fusarium wilt, and blights. Nematodes, potato tuberworms, and hornworms are the most common pests.

Nightshade toxins

Many members of the nightshade family contain toxic alkaloids believed to be defensive mechanisms against herbivores and insects. These alkaloids include the capsaicin responsible for chili peppers’ heat, and nicotine, which acts as an insecticide. Solanine and tropanes, two other alkaloids, can cause digestive upset at low doses and kill you at higher concentrations. The green skin sometimes seen on potatoes contains high levels of solanine. Be sure to remove and discard the green skin, if you want to avoid digestive problems a few hours later. The leaves and stems of nightshade plants should not be eaten or fed to pets, chickens, or livestock. It might not hurt them, but, then again, it might.

Tobacco flower (William Rafti) Public Domain

Belladonna flower (Flobbadob) CC BY-SA 4.0

In the case of the nightshade family, as in life, you need to pick your garden mates carefully.