Farmers test growing plants without soil

Tuesday , March 18, 2014 - 12:20 PM

Carol Lawrence

Looking at the rows of strawberries growing at Catalinos Berry Farms in Oxnard, Calif., one sees a subtle difference at Row 15.

That row begins 2 acres of experimental crops planted not in soil but in a mix of peat and coconut coir -- the coarse, hairy fibers extracted from a coconut's outer shell.

A closer look reveals the bunches of dark green leafy plants starting at Row 15 to be just slightly shorter and not as thick as those growing in soil.

Bill Reiman, general manager of the farm, who is growing the experimental strawberries, digs into the two growth mediums and pulls out handfuls of both.

The dirt soil is dark, moist, compacted and solid. The experimental mixture, or substrate, is lighter and fluffier.

"This contains the building blocks of building a plant," said Reiman, holding up the soil. Gesturing with the other hand, he said, "This contains none of that."

Reiman has been around strawberries since planting them in the 1980s in Maine. He now leads the California Strawberry Commission, and volunteered to do a larger field crop test of the experiments the commission has been doing for four years to see the yields of strawberries grown in substances other than soil.

Reiman joins four others in Santa Maria and Watsonville, the state's most bountiful areas for the berry, testing different combinations of coir and peat in a new joint research project between the California Department of Pesticide Regulation and the commission.

The organizations are using the $500,000, three-year project announced this month to find nonchemical alternatives to fumigants and reduce fumigant emissions, which can increase global warming. One path to that is to find other substances that strawberries will grow in that don't harbor the soil-borne diseases and pests that most farmers use fumigants to kill.

The experiment's results have potential significance for the state's 500 strawberry growers, shippers and processors, a number reported by the commission.

A move toward using soil alternatives would be an operational change for growers because the substrate is essentially sterile, free of the bad and good soil-based microbes, Reiman said. Fertilizers and nutrients must be added through watering, similar to hydroponics, or growing plants in water, and he installed four water lines for the rows.

Shifting to soil alternatives would wean growers off methyl bromide, the soil fumigant used for a range of crops but whose time is coming to an end.

Methyl bromide was phased out in 1995 as part of an international treaty to halt the depletion of the ozone layer. Agricultural growers may continue using it only because there are no technically or economically feasible alternatives.

The primary obstacle to using the substrate is cost, Reiman said. For 1 acre of plants at Catalinos Berry Farms, the coir-peat mix costs $10,000, he said, and that is on top of regular operating costs. Pesticides are only a "minimal" cost.

"The current cost structure is not economically viable, and we can't afford to do it," Reiman said. "Consumers are still price buyers, so that has to be part of the equation."

Consumers would have to pay double and maybe triple what they pay now, Reiman said. When the cost gets too high for a product, the public tends to lose the taste for it.

What may offset that high cost is a coir-peat mixture that is highly recyclable, something the commission said it also will test.

Another obstacle Reiman sees is the amount of fruit substrates will yield.

The plants were shorter and didn't spread as much, and while Reiman said he had "no complaints" on their health or plant structure, he said the yield was "not even close" to the yield from the soil-grown plants.

European and other countries have used substrates for years, but their production level is "a fraction of what it is in the U.S.," said Carolyn O'Donnell, communications director for the commission.

In the U.S., 71/2 pounds of strawberries are consumed per person a year, with 88 percent of the nation's strawberries grown in California in 2010, she said.

Reiman appeared cautiously optimistic about the experiments.

Over time, he said, changes in technology and processes may enable growers to match soil's yields of strawberries.

"We have to push to do something better in terms of quantity, quality and price," Reiman said. "It's all part of the equation."

(Contact Carol Lawrence of the Ventura County Star in California at

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