Growers thinking ‘outside the garden’
It seems like those hanging pots with a tomato sticking out the bottom are popping up everywhere as the upside-down tomato craze catches on.
The advertisements promise tomato crops that are bigger, better tasting, healthier, and easier to grow than ever before. Is this a revolutionary production system, or just a fad?
“In discussion with horticultural staff at Iowa State University, we have agreed that the upside down tomatoes are more of a novelty or gimmick than anything,” said Gary Hall, director of Cerro Gordo County Exension. “Sure, you can make them grow and even produce a few tomatoes, but you could do the same thing in a container on your patio with less trouble.”
In the upside-down system, the plant will actually try to grow right side up. While the roots will be at the bottom of the container as they are moving toward gravity, the plants will try to grow up toward the sun. The plants appear to grow down because of the weight of the tomatoes, Hall said.
This spring, Mark Wilkins, who runs the NAPA store in Lake City, decided to try an upside-down tomato that he purchased at the local dime store for about $10.
The bag, which is hanging outside on the west end of his store, contains one tomato plant that Wilkins purchased from a nursery in town.
“The wind has been kind of hard on it, but we’ll see what happens,” said Wilkins, who noted that the tomato’s stem was curving and growing upwards by Memorial Day.
While gardeners continue to scrutinize the pros and cons of the upside-down tomato system, almost any container can be used to grow tomatoes, as long as it’s deep enough for the roots and provides good drainage.
Jim Dougherty, who farms in the Lake City/Yetter area, said he began growing tomatoes in pots a number of years ago before switching five years ago to a self-watering box designed specifically for tomato plants.
“There’s hardly any work with this system,” said Dougherty, who favors Celebrity tomatoes for their disease resistance and good yields. “It’s convenient, because I can put the box south of the house where the plants will get the most sun, and there are few, if any, weed problems.”
Dougherty fills the box, which he purchased through a mail-order company, with new potting soil each spring. He then puts two young tomato plants in the container, fills the reservoir with four to five gallons of water, and adds a layer of wood chip mulch to prevent the soil from drying out too quickly.
As the plants grow, he applies liquid fertilizer every week or two. “Even on the hottest days of the summer, I only have to fill the water reservoir every few days,” he added.
Follow the basics
No matter what form it takes, container gardening continues to grow in popularity, since it overcomes the challenges of poor garden soil, limited space, lack of sun in the garden area and even the gardener’s impaired mobility.
Containers, which allow a movable garden with the opportunity for a limited supply of vegetables, also offer a unique way to introduce children to gardening.
It’s important to start with the soil when container gardening. Since the plants will require a growing medium that drains well, yet does not dry out too fast, avoid 100 percent garden soil, which is too heavy and may contain disease organisms.
Soil-less potting mixes work well because they are less likely to compact, are free of weed seeds and are lightweight. Cherry tomatoes require one gallon of potting soil for one plant, while a standard tomato requires about three gallons of soil for one plant, according to ISU Extension.
Tomatoes grow best in full sunlight, so containers should be placed where they will receive at least six hours of sunlight per day. Varieties of tomatoes that work well in containers include Jetstar, Celebrity and Super Bush for standard tomato varieties, said Hall, who added that Pixie is a good variety for a cherry tomato.
Plants grown in containers require frequent watering, because they dry out quickly from sun and wind. Apply enough water to reach the bottom of the container and allow the excess to drain through the drainage holes. Never allow the soil to dry out completely between waterings; this may cause the plants to drop their fruits and flowers.
However, overwatering also will slowly kill plants, because the roots will not receive enough oxygen.
“When watering, avoid wetting the leaves, especially if watering late in the day, because wet leaves encourage the development of plant diseases,” said Richard Jauron, an ISU Extension horticulturist.
Container-grown plants require fertilization more frequently than field-grown vegetables, because they have less soil from which to obtain nutrients. ISU Extension recommends a soluble fertilizer (15-30-15 or 20-20-20) applied once every week or two. The fertilizer can be applied while watering, Jauron said.
When growing standard-sized tomato varieties in a container, use a stake or cage to keep the vines upright. Tie the stems loosely to the stake. Tomato cages should be made of fencing material of at least 4-inch mesh so the fruit can be harvested easily. Cages should be at least 24 inches in diameter, according to ISU Extension.
At the end of the growing season, discard the entire contents of each container. Do not reuse the potting mix the next year to avoid the risk of spreading diseases that may be present in the mix or on the plant debris.
“Whether you raise your plants upside down or right side up, I hope you have a great time watching them grow and enjoying those fresh, red, juicy tomatoes,” Hall said.
Contact Darcy Dougherty Maulsby at email@example.com.
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