Growing Tomatoes Upside Down: Fine, But Why?

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20170516A

Upside down tomato: notice the plant is vainly struggling to grow upward.

Sure, you can grow tomatoes upside down, with the roots on top and the stems, leaves, flowers and fruits underneath. You can grow almost any plant upside down. There are commercial systems—basically a pot with a hole in the bottom—specifically intended for this type of culture, but you can save a lot by converting a simple plastic bucket into a pot for upside down tomatoes.

All this is quite possible and is not even really surprising. Any plant that gets knocked sideways or even upside down, say in a landslide, will try to survive. By planting a tomato plant upside down, you’re only bringing out its survival instinct.

The question to ask, though, is why? What’s so interesting about growing a tomato upside down?

Curiosity Factor

True enough, there’s curiosity. Cultivating a plant upside down could be an interesting project for a group of students. Or for an adult to try, just once, to see how it works. But otherwise, when you look carefully at the so-called benefits, you’ll find there really aren’t many.

As seen on TV!

Yes, that notice appears in several ads for upside down tomato containers, but since when is a product that appears on television better than a product that’s not seen on TV? Personally, when I see “as seen on TV,” I tend to automatically think the product must be a scam of some sort!

False Advantages

20170516B.jpgThe sellers of these pots claim that a tomato plant grown upside down will have certain advantages. Perhaps, but it’s worth noting that the following benefits, often cited, also apply to any tomato grown in pots as compared to a tomato grown in the ground. The plant does not need to grow upside down to be:

  • An excellent choice for small-space gardens;
  • Free of weeds;
  • Free of cutworms and other soil insects;
  • Less prone to soil diseases;
  • Easy to install almost anywhere;
  • Easy to bring indoors quickly in case of frost;
  • More productive in cold regions since the pot is heated by the sun;
  • Simple to grow on a balcony or patio.

Place a pot of tomatoes upright on a sunny terrace or balcony and all the same benefits apply.

There is even one company that claims that their pot gives you organic tomatoes! Obviously, a plant grown upside down is not “more organic” than a plant grown upright. It will only be organic if you don’t use synthetic pesticides or fertilizers. Organic gardening has nothing to do with a plant’s orientation.

True Advantages

There are two advantages of growing tomatoes upside down:

  • An upside down plant will not need a staking or a tomato cage… but is that really that much of a problem?
  • It’s true the plant will take up a bit less space, because even if the plant tries to stretch out in all directions, including sideways, the weight of the stems will eventually pull them nearly straight down, ensuring a narrower silhouette. But that’s compared to a tomato growing freely, without staking. You could tie a tomato plant tightly to a stake and obtain an even narrower plant.

Disadvantages

20170516C Thomas Kriese, Flickr.jpg

Tomato grow upside down in a bucket: less expensive that a commercial upside down tomato pot. Thomas Kriese, Flicker

What you are not told is that:

  • Installing a tomato plant in an upside down pot requires a certain dexterity. Most systems require you to push either the leaves or the roots through a narrow hole and often the stem ends up snapping off or the roots are damaged;
  • When filled with soil, the container will weigh a lot (about 50 pounds/23 kilograms for most commercial models) and that will make it difficult to hoist into place or to move. That’s enough weight to damage some structures you might want to use to support the pot. Certainly you’d need a very strong hook fixed into a solid support;
  • Tomatoes produce fewer flowers and subsequently fewer fruits when grown upside down. This is the case for almost all plants. The hormones that stimulate flowering tend to accumulate in erect stems and to decrease in drooping ones. You’ll notice that fruits only form on those stems that manage to grow upright: any that hang limply down won’t produce fruit. All summer long you’ll watch as the plant vainly struggles to right itself, with its stems growing upwards at the tip (these will flower and bloom), but eventually their own weight drags them down;
  • Since the plant hangs underneath a pot that creates shade, it won’t receive as much direct sunlight when the sun is directly overhead as would an erect plant growing out in the open;
  • The initial cost of the pot means that the tomatoes produced are expensive. Since plants grown upside down produce fewer tomatoes, that’s an investment you’ll never recuperate;
  • Watering is more complex in an upside down pot. Often people water less than they really should, leaving the plant a bit drought-stressed, in order to avoid surplus water and soil from dripping onto the fruit, possibly carrying diseases, or dirtying a balcony floor. That’s why many modern models include a semi-automated irrigation system to ensure that water gets to the plant drop by drop through a water reservoir;
  • Watering becomes a risky procedure for gardeners, as most will need to stand on a stool or step ladder to water… and to do so while lifting a heavy watering can;
  • The choice of tomato plant has to be limited to determinate tomatoes, which are less productive than indeterminate tomatoes, because indeterminate tomatoes produce stems that are too long. (See The Tall and Short of Tomatoes for an explanation of “determinate” and “indeterminate” tomatoes.)

Totally Bogus Claims

20170516E.jpgSome advertisements make totally bogus claims.

  • Eliminates the use of pesticides.

That’s nonsense, of course. Container-grown tomatoes, whether upside down or right side up, tend to have fewer insect and disease problems than tomatoes grown in the ground, but still, pesticides may still be needed.

  • Water and nutrients pour directly from the root to the fruit.

This suggests that water and minerals move through plants by the force of gravity, but that simply isn’t true. Xylem tissues carry sap from cell to cell, largely by a combination of capillary action and evapotranspiration. Gravity is not a major factor and sap doesn’t flow downward faster than it flows upward.

  • Tomatoes grow bigger and are more delicious.

That’s pure fantasy. How the fruit is oriented doesn’t change its size or taste.

Note that the three claims mentioned above were from ads on the websites of Chinese manufacturers. I suspect that consumer protection laws are much less rigorous in China than in the West!

Not Even a New Concept

If you think these inverted pots are a state-of-the-art idea, you’re wrong. People have been experimenting with growing plants upside down since the days of the hanging gardens of Babylon more than 2000 years ago. Commercial pots designed for growing tomatoes upside down have been around for a long time too, probably at least 30 years. One company claims to have sold more than 10 million of these pots and that simply doesn’t happen overnight.

The End Result

Most gardeners who buy such a pot are very enthusiastic at first and ready to recommend it to anybody. Yet if you come back three years later, you’ll generally see that they have abandoned this way of growing tomatoes and that the pot has been stored away somewhere, never to be used again.

Upside down tomatoes: much ago about nothing!

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