A pomato (often sold under commercial trade names like “TomTato” or “Ketchup ‘n’ Fries”) is a real, dual-bearing plant that produces cherry tomatoes above ground and white potatoes underground on a single vine. However, it is not a genetically engineered hybrid, a mutant cross-breed, or a brand-new species. There is no such thing as a “pomato fruit.” Instead, the plant is a physical horticultural graft that splices the fruiting stem (scion) of an ordinary tomato plant onto the root system (rootstock) of an ordinary potato plant. Because both species belong to the genus Solanum within the nightshade family (Solanaceae), their vascular tissues naturally fuse and share water and nutrients. While physical grafting allows both vegetables to grow simultaneously, the plant cannot reproduce itself. Planting the harvested potatoes will grow only normal potato plants, and saving seeds from the tomatoes will grow only standard tomato vines.
How a Grafted Pomato Works
Potatoes and tomatoes are closely related. They are both part of the nightshade family (Solanaceae) and share the same genus, Solanum. Because their cellular anatomy is so compatible, you can take a scion (a young shoot) from a tomato plant and splice it directly onto the cut stem of a potato plant. The two vascular systems fuse, cooperate fully, and continue growing.
The potato plant forms the rootstock, anchoring the plant and forming underground tubers. The grafted tomato top forms the foliage, flowering branches, and fruit.
In theory, the combined plant enjoys distinct advantages from both species:
- Temperature Resilience: Potatoes tolerate colder soil temperatures than tender tomatoes, giving the root system a slight edge in early spring frosts.
- Foliage Heat Tolerance: The tomato canopy handles intense mid-summer heat better than potato foliage, which often wilts when temperatures spike.
The Stone Fruit Myth: Just like the pomato is mistaken for a lab-engineered hybrid fruit, another familiar grocery staple has tricked eaters for generations. Millions of people grew up believing the smooth skin of a nectarine proved it was a cross between a peach and a plum. In reality, it is a 100% natural mutation of a standard peach that simply lacks the gene for fuzz. Discover how nature pulled off this ancient genetic trick in Nectarine vs. Plum: Is a Nectarine a Peach-Plum Hybrid?.
The Cherry Tomato Secret: Photosynthetic “Sink” Competition
While virtually any tomato variety can physically take to a potato rootstock, commercial nurseries like the makers of the “TomTato” almost exclusively use indeterminate cherry tomatoes. This isn’t an arbitrary choice. It comes down to a problem of resource competition:
- Nutrient Sinks: In plant physiology, developing fruits and swelling tubers are known as carbohydrate “sinks.” Potatoes demand immense amounts of starches directed downward to swell underground tubers. If you graft a heavy slicing or beefsteak tomato onto a potato root, both ends of the plant engage in a brutal tug-of-war for limited photosynthetic sugars. The result is almost always stunted, hollow tomatoes and marble-sized potatoes. Small cherry tomatoes demand far less energy per fruit, allowing the plant to balance both harvests.
- Mechanical Weak Points: A grafted herbaceous stem never achieves the full structural integrity of an undisturbed seedling. A heavy vine weighted down by clusters of 10-ounce beefsteak tomatoes exerts massive torque on the splice union, easily snapping the plant during high winds. Lightweight cherry tomato trusses protect the fragile graft.
The Disease Problem
While dual-cropping sounds ideal for small spaces, splicing the two plants together creates a significant horticultural liability: cross-species disease transfer.
Potatoes and tomatoes are vulnerable to many of the same devastating pathogens, including late blight (Phytophthora infestans), tobacco mosaic virus, and various bacterial wilts. In standard agricultural practice, potatoes and tomatoes are planted as far apart as possible to prevent cross-contamination. On a pomato plant, they share same vascular pathway. If the tomato foliage catches blight from airborne spores, the infection travels straight down into the root system to rot the tubers, and vice versa.
Physical Graft vs. Genetic Hybrid: Key Differences
The pomato continues to cause confusion online. Most of this confusion stems from a misunderstanding about the difference between a commercial nursery graft and true botanical hybridization:
The Real Potato-Tomato Hybridization Attempts
There have indeed been serious scientific attempts to create a real pomato, a plant engineered at the cellular level that would possess novel genetic characteristics and produce a genuinely new kind of fruit.
Parade-raining time: such efforts were never truly successful.
The first experiment to produce a somatic pomato was performed by Georg Melchers of the Max Planck Institute for Biology in Tübingen in 1977. Using protoplast fusion, a technique where the protective outer cell walls are stripped away using enzymes so the naked cellular membranes of two distinct species can fuse, he managed to generate a hybrid plant.
The scientific dream was to engineer a plant that carried productive potato tubers below ground and heavy tomato crops above ground, with the ability to reproduce normally as a unified species. Unfortunately, Melchers’ fused plants produced neither edible potatoes nor edible tomatoes. While potatoes and tomatoes are close relatives, their chromosomes cannot easily align to produce fertile, functional reproductive organs.
In 1994, another attempt at somatic hybridization was conducted at the Max Planck Institute for Plant Breeding. Researcher Lewen-Dörr and a company called Green Tec produced hybridized plants that were described as “vigorous.” Yet despite their strength, they behaved almost entirely like potato plants with a single cosmetic mutation: they produced yellow flowers instead of typical white or off-white potato blossoms.
The somatic hybridization attempted in these experiments does work in some agricultural sectors. It’s routinely used to breed new citrus cultivars, for instance. But citrus varieties are far more genetically compatible than potatoes and tomatoes and routinely hybridize naturally in the wild without any input from humans.
Let’s Throw in Some Eggplants: The “Brimato”
The internet’s love affair with multi-crop nightshades doesn’t stop at tomatoes and potatoes. An article in The Times of India once described a “brimato” plant, touting it as an astonishing agricultural engineering breakthrough.
In reality, researchers simply created a standard potato-and-tomato graft, and then grafted an eggplant (brinjal in India) scion onto the upper stem. Eggplants also belong to the Solanaceae family, so their tissue fuses just as easily.
It was a horticultural assembly trick, not a genetic hybrid. A true hybrid produces a brand-new, unified fruit sharing the traits of its parentage. Splicing three distinct stems together merely creates a living novelty rack producing three genetically distinct vegetables on a shared root.
Grafting Is a Practical Tool, Not a Species
Grafting plants and fruit trees is a standard, centuries-old horticultural practice. For instance, species within the Prunus genus (plums, nectarines, apricots, cherries, and peaches) are routinely grafted onto a single rootstock to create multi-bearing “fruit salad” trees.
Yet nobody expects those branches to yield a mutant “Plumeachacrot.” The tree simply possesses a peach root system feeding separate branches that produce ordinary plums or ordinary apricots.
There is nothing wrong with growing a grafted pomato. For gardeners with limited space, such as urban rooftop growers or container gardeners using deep 15-gallon patio planters, a pomato offers a fun dual harvest from a single footprint.
Just don’t let viral headlines or marketing gimmicks convince you that science has invented a miracle crop. At the end of the season, you are still harvesting ordinary cherry tomatoes from the vine, digging ordinary white potatoes from the dirt, and having to buy a brand-new nursery graft if you want to do it again next year. It’s far easier to plant separate tomatoes and potatoes.
Further Reading
- Where is the Blackberry Juice? The Food Science of a Missing Grocery Staple
- Is Red Food Dye Made from Crushed Bugs? The Carmine & Cochineal Reality