PESTICIDE BAN DRIVES SWITCH
TO SOILLESS AGRICULTURE

UF/IFAS NEWS RELEASE
originally written by Chuck Woods
sources: Bob Hochmuth, Eric Waldo, and Marvin Brown January 2000

LIVE OAK---Faced with a 2005 ban on a widely used chemical that controls soil pests, University of Florida researchers are working with growers to develop new high-tech growing methods that eliminate the need for soil.

Strawberries being grown in perlite growbags!

"Soilless agriculture is not the wave of the future, it's already here," said Bob Hochmuth, a vegetable expert with UF's Institute of Food and Agricultural Sciences, who says the new growing methods have caught the attention of growers around state -- especially for high-value crops such as tomatoes, colored bell peppers, cucumbers, Bibb lettuce, herbs and strawberries.

"We're losing a valuable pesticide called methyl bromide because the federal Environmental Protection Agency has found it contributes to the destruction of the Earth's protective ozone layer in the atmosphere, so it makes sense to move production of some high-value crops out of the soil altogether," he said.

"In fact, some growers are desperately looking for alternatives to growing crops outdoors in disease-infested fields, and they're turning to greenhouse production and soilless growing mediums, commonly known as hydroponics," Hochmuth said. "All plant nutrients are supplied in the irrigation water."

He said most South Florida hydroponic production is in Collier, St. Lucie and Palm Beach counties, and almost all North Florida hydroponic production is in Suwannee County. Statewide, there are now more than 70 acres of crops under protective cover. Strawberry growers in Hillsborough County also are looking at growing their crops outdoors in hydroponic systems.

The value of hydroponic crops produced in Florida totals about $14 million, a mere fraction of the estimated $1.54 billion in regular field-grown vegetables.

Hochmuth, a multicounty extension agent based at UF's Suwannee Valley Research and Education Center in Live Oak, said hydroponics is a more expensive way to grow crops, but there are many advantages, especially on crops such as tomatoes and strawberries.

A typical "field" of strawberries being grown in 100% perlite growbags

"Growers can sell tomatoes for $2 to $3 per pound, and the cost of producing greenhouse hydroponic vegetables ranges from $2 to $15 per square foot," he said. "But those higher costs can be offset by higher production -- up to 10 times higher than field-grown produce."

Hochmuth said longer marketing seasons are another big advantage for greenhouse hydroponic crops. And, since they're not subjected to the usual insect pests, weather conditions and other kinds of damage, greenhouse crops have a better appearance for consumers and generally fetch higher prices for growers.

He said the switch to hydroponics, which includes the use of inorganic growing media such as perlite, makes it easier to avoid soilborne pests and diseases that can affect the quality and appearance of high-value crops.

In tests at the UF's Gulf Coast Research and Education Center in Dover, Hillsborough Extension Agent Eric Waldo and horticulturalist John Duval are conducting a research and demonstration project to learn how well strawberries grow outdoors in bags filled with perlite and other inorganic growing media.

"So far, the early results are encouraging, with higher yields from plants in bags of perlite than from regular soil-grown plants," Waldo said.

"Essentially, what we're doing is growing strawberries in an outdoor hydroponic system, supplying all the nutrients in irrigation water," Waldo said. "The bags of perlite provide an inorganic growing medium for plant roots, but the perlite has no nutrients or any of the harmful organisms that typically infest regular soil."

Operating equipment of a typical "field" of strawberries

While the cost of using perlite bags is higher than regular soil, growers would not have the expense associated with methyl bromide soil fumigation and herbicides for weed control.

With the coming ban on methyl bromide, Waldo said it will give strawberry growers in the Plant City and Dover areas an alternative to growing their crops in soils that are infested with nematodes and diseases.

Marvin Brown, president of BBI Produce Inc. in Dover, the state's largest grower and shipper of fresh strawberries, said soilless strawberry production -- although still in its infancy -- could be a part of his future.

"With the rapidly approaching deadline for discontinuing use of methyl bromide as a soil fumigant and no viable replacement in sight, soilless alternatives deserve serious attention," Brown said. "Advancements in technology and growing techniques will undoubtedly increase our desire and ability to use alternative production methods that are both economical and ecologically acceptable to all."

For more information about the work of the University of Florida's IFAS (Institute of Food and Agricultural Sciences): go to IFAS Print News Releases