A tray of unlabeled seedlings looks nearly identical by the second true leaf. Tomato, pepper, eggplant, and potato all share the same plant family.
The confusion is not imagined. It is built into their shared ancestry.
Plants that look like tomatoes fall into two groups. Some are genuine cultivated relatives that share the nightshade family Solanaceae. Others are volunteer relatives, like ground cherries, that show up uninvited and grow in a similar way.
This guide covers how to tell each one apart. It starts at the seedling stage, where most of the confusion actually happens.
The short version
Potato, pepper, and eggplant are the three plants most often confused with tomato seedlings, since all four belong to Solanaceae. A smell test settles most cases. Rubbed tomato foliage carries a sharp, unmistakable scent that pepper leaves do not share.
Eggplant gives itself away with a spiny stem and coarser leaves. Potato foliage looks similar but runs a bluer green, and a potato plant can even set small tomato like fruit if left to flower.
Ground cherries and tomatillos are lower growing and sprawl more than a young tomato plant. Both eventually wrap their fruit in a telltale papery husk.
Potato: the closest relative in the garden
Potato and tomato share the same genus, Solanum. That explains why their foliage looks so similar at a glance, since both grow compound leaves made of several smaller leaflets along a central stem.
The tell is color and posture. Potato foliage runs a slightly bluer, more matte green than a tomato’s brighter leaf. The plant also tends to grow lower and bushier, rather than reaching upward the way a staked tomato does.
The strangest overlap shows up later in the season. A potato plant left to flower can set small green fruit that looks disturbingly like a cherry tomato. It is genuinely poisonous and should never be eaten, even though the resemblance is close enough to fool an experienced gardener.
Pepper: similar leaves, no tomato smell
Pepper plants share the family but not the giveaway scent. Home gardeners on plant identification forums lean on this test constantly. Rub the leaves, and if there is no sharp tomato smell, the plant probably is not a tomato.
Pepper leaves are also smoother and glossier than a tomato’s fuzzy, deeply lobed foliage. A tomato leaf is compound and toothed along the edges. A pepper leaf, by contrast, is simple, with a smooth, unbroken margin.
Growth habit differs too. Pepper plants stay more compact and upright from the start. Young tomato seedlings, especially under low light, often show sprawling, floppy stems that a pepper seedling does not.
Eggplant: the spiny stem gives it away
Eggplant belongs to the same nightshade family as tomato, potato, and pepper. Its leaves are large and coarse, noticeably heavier in texture than a tomato’s finer, more deeply cut foliage.
The clearest identifying feature is the stem. Eggplant stems are often spiny, a texture no tomato seedling ever has, even on the fuzziest heirloom varieties.
Toxicity runs the opposite direction from the fruit, too. Eggplant leaves and flowers are poisonous even though the fruit itself is a common vegetable. A tomato plant’s leaves carry a milder version of the same alkaloid family, still worth keeping away from pets and small children.
Ground cherry and tomatillo: the sprawling cousins
These two are true tomato relatives, not just lookalikes, but their growth habit sets them apart early. Ground cherry plants stay under 30 inches tall and tend to sprawl outward rather than climb upright the way a tomato does.
Tomatillo plants go the other direction. They grow bushier and often larger than a tomato plant, easily needing 3 feet of space per plant in a home garden bed.
Both eventually produce the unmistakable giveaway. It is a small fruit wrapped entirely in a papery, lantern shaped husk that no tomato variety ever grows.
Seed starting timing offers one more clue before any fruit appears. Ground cherries typically need six to seven weeks indoors before transplanting, a week or two longer than most tomato varieties need.
Frequently asked questions
How can you tell a tomato seedling from a pepper seedling?
Rub a leaf and smell it. Tomato foliage has a sharp, distinctive scent that pepper leaves do not share, and it is the fastest test home gardeners use.
Tomato leaves are also compound and toothed, while pepper leaves are simple and smooth edged.
Why do potato plants look so much like tomato plants?
Potato and tomato belong to the same genus, Solanum, so their compound leaf structure looks nearly identical at a glance. Potato foliage runs a bit bluer and more matte, and the plant grows lower and bushier than a staked tomato.
What plant has spiny stems but otherwise looks like a tomato?
Eggplant. Its stem is often spiny, unlike any tomato variety, and its leaves are larger and coarser than a tomato’s finer, more deeply lobed foliage.
Are ground cherries the same thing as tomatoes?
No, though they are true relatives in the nightshade family. Ground cherry and tomatillo plants sprawl or bush out more than tomatoes.
They eventually produce fruit wrapped in a distinctive papery husk that no tomato ever grows.
Can a potato plant actually grow something that looks like a tomato?
Yes. A potato plant left to flower can set small green fruit that closely resembles a cherry tomato.
It is poisonous, though, and should be discarded rather than eaten.
Bottom line: most plants that look like tomatoes turn out to be actual relatives sharing the nightshade family, which is exactly why the leaves and stems look so familiar. A smell test separates tomato from pepper fastest, a spiny stem points to eggplant, bluer foliage points to potato, and a papery husk always means a ground cherry or tomatillo rather than a tomato. For the specific fruit these lookalikes eventually produce, see this site’s guide to fruits that look like tomatoes at https://knowtomato.com/fruit-that-looks-like-a-tomato/.
SOURCES
University of Florida IFAS Gardening Solutions: Eggplant. https://gardeningsolutions.ifas.ufl.edu/plants/edibles/vegetables/eggplant/
University of Florida IFAS Gardening Solutions, Master Gardener Plant Identification: Tomato. https://gardeningsolutions.ifas.ufl.edu/mastergardener/outreach/plant_id/vegetables/tomato.shtml
University of Minnesota Extension: Growing Tomatillos and Ground Cherries in Home Gardens. https://extension.umn.edu/vegetables/growing-tomatillos-and-ground-cherries
University of Arkansas Cooperative Extension Service: Tomatoes or Potatoes? What Is This Fruit on My Potato Plant? https://www.uaex.uada.edu/counties/white/news/horticulture/202007Tomatoes_or_Potatoes.aspx