You've probably seen the photos. A single, leafy green plant looks perfectly normal above the soil, heavy with clusters of bright red cherry tomatoes. But then, a hand pulls the plant upward, revealing a cluster of smooth white potatoes clinging to the roots. It looks like a miracle of modern bioengineering or maybe a glitch in the matrix.
It's called a hybrid potato tomato plant, though "hybrid" is actually a bit of a misnomer in the scientific sense. You can’t cross-breed a potato and a tomato through pollination to get a "pomato" seed. They are different species. However, because they both belong to the Solanaceae (nightshade) family, they are compatible enough to be physically joined together through a process called grafting.
Honestly, it’s a weirdly fascinating bit of horticulture that’s been around much longer than most people realize.
The Science of the Graft: It Isn't Magic
A lot of people think the pomato is a GMO. It’s not. There is no gene splicing involved here. Instead, it’s a mechanical process.
To make a hybrid potato tomato plant, you take a potato variety (the rootstock) and a tomato variety (the scion). You cut a notch into the stem of the potato plant and slide the sliced stem of the tomato plant into it. If you wrap it tightly and keep the humidity high, the vascular tissues—the xylem and phloem—eventually fuse. They start sharing nutrients. The potato roots drink up water and minerals from the soil, sending them up to the tomato leaves. In return, the tomato leaves photosynthesize and send sugars down to grow the potato tubers.
It’s basically a biological transplant.
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This works because potatoes and tomatoes are cousins. They share a similar internal "plumbing" system. If you tried this with, say, a tomato and a cucumber, the graft would rot and die within days because their vascular structures don't line up.
Why does this matter for your garden?
Space. That’s the big selling point. If you have a tiny balcony or a square-foot garden, the idea of getting two crops from the footprint of one is incredibly tempting. Companies like Thompson & Morgan brought this to the mainstream a few years ago with their "TomTato" brand. They didn't invent the concept—Luther Burbank was experimenting with similar ideas over a century ago—but they perfected the commercial grafting process so the plants could survive shipping.
The Reality Check: Is It Actually Worth It?
Here is the thing about the hybrid potato tomato plant that the glossy catalogs don't always mention: it is a high-maintenance diva.
Plants have an energy budget. Every bit of sunlight captured by the tomato leaves has to be partitioned. Does the plant send that energy into making a bigger, juicier tomato, or does it store it underground to make a starchier potato? Usually, you get a trade-off. You might get a decent crop of tomatoes, but the potatoes end up being the size of golf balls. Or, if the potato variety is particularly aggressive, it might "choke out" the tomato graft before you even get a harvest.
Then there’s the issue of timing.
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Potatoes usually want to be harvested when the foliage dies back. Tomatoes, however, need that foliage to stay green and healthy until the very last fruit ripens. If you dig up your potatoes too early, you kill your tomato plant. If you wait for the tomatoes to finish, your potatoes might start to rot in the damp soil or get hit by late-season blight.
It’s a balancing act. It’s difficult.
Debunking the "Frankenfood" Myths
You'll see weird rumors online. Some claim that the tomatoes will taste like potatoes or vice versa. That’s just not how plant biology works. The DNA of the fruit is determined by the scion (the top part), and the DNA of the tuber is determined by the rootstock.
- Taste: The tomatoes will taste exactly like the variety you grafted (usually a cherry tomato like 'Sungold' or 'Sweet 100').
- Safety: There is a common myth that the plant becomes toxic. While both plants are nightshades and contain solanine (which is toxic in high amounts), the edible parts remain perfectly safe. You shouldn't eat potato leaves anyway, regardless of whether there’s a tomato attached to them.
- Longevity: These are annuals. You can’t save the seeds to grow another pomato next year. If you plant a seed from a pomato tomato, you’ll just get a regular tomato plant.
How to Try This at Home (The Honest Way)
If you’re feeling brave and want to DIY your own hybrid potato tomato plant, don't expect a 100% success rate. Even pro nurseries lose a lot of plants during the "healing" phase after grafting.
- Start with similar stem thicknesses. This is crucial. If your potato stem is a giant pipe and your tomato stem is a tiny straw, they won't fuse. You want them to be about the diameter of a pencil.
- The "V" Graft. Most people use a cleft graft. You cut a V-shape into the potato stem and a matching wedge into the tomato stem.
- Sanitation is everything. If you use a dirty knife, you’re just injecting bacteria into the plant’s "bloodstream." Use a razor blade dipped in rubbing alcohol.
- The Humidity Chamber. After grafting, the tomato top has no way to get water until the tissues fuse. You have to keep it in a very humid environment—like under a plastic bag or in a misting house—for about a week. Keep it out of direct sunlight during this time, or it will wilt and bake.
The Verdict on the Hybrid Potato Tomato Plant
Is it a gimmick? Sorta.
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If you have an acre of land, there is zero reason to grow a pomato. Just plant a row of potatoes and a row of tomatoes. They’ll both be happier, produce more, and be easier to manage.
But if you are a "mad scientist" gardener or someone living in a high-rise apartment with a single large pot on the balcony, the hybrid potato tomato plant is a fun, legitimate experiment. It’s a conversation starter. There is something undeniably cool about harvesting your salad and your fries from the same bucket.
Just don't expect it to solve world hunger. It’s a feat of horticultural skill, not a replacement for traditional farming.
Actionable Steps for Success
If you're going to buy or grow one, keep these specific tips in mind to actually get a harvest:
- Use a Large Container: We are talking at least 10 to 15 gallons. Both potatoes and tomatoes are "heavy feeders." They need a massive amount of nutrients and root space.
- Deep Feeding: Use a balanced organic fertilizer early on, but switch to something higher in potassium once you see flowers. Potassium helps with both fruit development and tuber swelling.
- Support is Mandatory: The graft union is a weak point. If a strong wind hits a heavy tomato crop, it can literally snap the plant in half at the graft site. Use a sturdy cage or tie the main stem to a heavy-duty stake.
- Pruning: Keep the potato "suckers" in check. Sometimes the potato base will try to grow its own leaves from below the graft. Snip those off immediately. You want all the green energy coming from the tomato leaves, not the potato.
- Watch the Water: In a pot, the soil can dry out fast. Uneven watering leads to blossom end rot in the tomatoes and "hollow heart" in the potatoes. Consistency is your best friend.
Ultimately, the pomato is a testament to the versatility of the Solanaceae family. It reminds us that plants are far more adaptable than we give them credit for. Whether you see it as a gardening masterpiece or a weird novelty, it’s a living example of how we can nudge nature into doing something spectacular.
Get your supplies ready. Sharpen your blades. If you're going to attempt the graft, do it in early spring when the plants are at their most vigorous. Even if the graft fails, you’ll learn more about plant anatomy in one afternoon than you would in a year of reading textbooks.