Strawberry Fields Forever?

When Soil Muddies Sustainability


Summer 2018 | Julie Guthman,

ld-school organic growers are up in arms about the 2017 National Organic Standards Board (NOSB) decision to allow hydroponic, aquaponic, and aeroponic farms to obtain organic certification. By an eight-to-seven vote, the national body charged with setting organic standards rejected a proposal to prohibit these practices in organic crop production.1 Although such practices have long been allowed under the organic rubric, the recent rise in high-tech, indoor soilless systems brought new energy to a simmering debate. Indoor farming is no longer a sideline of Northeast organic farmers seeking to produce a taste of summer in the midst of winter. Instead, it is attracting major investment — part of a tidal wave of “agtech” innovation aimed at sustainability and high profitability in a sector not known for either. As reported by AgFunderNews, novel farming system start-ups (of which soilless systems are a part) saw “remarkable” growth in 2017, “increasing by 233 percent year-over-year to $652 million across 57 deals.”2

For many organic growers, soilless systems are anathema to a production approach whose philosophical roots lie in healthy soil. Drawing on the writings of Sir Albert Howard, they see lively, biodiverse soil as a bedrock, as it were, to growing healthy plants and nutritious food, and indeed, avoiding the use of toxic inputs.3 They thus see the NOSB’s decision as the final insult to already watered-down organic standards, and under the auspices of the “Real Organic Project” and “regenerative agriculture” are calling for new means to differentiate hydroponic systems from soil-based ones.4 Those championing soilless systems, which tend to go hand-in-hand with high-tech, highly controlled conditions that must be managed indoors, point to the meaning that organic has come to have for the vast majority of the public: grown without pesticides. With so many diseases arising in the soil, they see hydroponics as a way to curtail agrochemical use. Plus, indoor farming presents an opportunity to grow fresh fruits and vegetables year-round and meet the growing demand for healthy food that is not transported thousands of miles.

Putting aside the question of whether soilless systems should be allowed under the organic rubric (I tend to think not, if for no other reason than to honor the roots of organic farming), this debate raises additional questions about the difficulty of adjudicating among the many principles of sustainability in any farming system when these principles come to be at odds. Feeding the soil, reducing food miles, attending to local conditions of production, eliminating toxic inputs, and reducing the use of nonrecyclable material and nonrenewable energy are easier said than done when attempted all at once. With social justice concerns thrown into the mix, such as improving pay and working conditions for farm workers and keeping prices affordable for low-income consumers, meeting multiple goals of sustainability becomes all but impossible. Indeed, these different ideals and emphases have long been fracturing points for the organic movement, as I documented in my book Agrarian Dreams.5

Today, such tensions are particularly salient for the California strawberry industry, faced as it is with tighter restrictions on a set of chemical soil fumigants that have allowed it to produce relatively affordable fruit nearly year-round for a national market, making the strawberry the state’s sixth most important crop in terms of value of crops sold.6 Although strawberry producers can continue to use some of these chemical solutions (albeit under constrained conditions), fear of their eventual phase-out has introduced an imperative to grow without them — and thus adopt at least one principle of sustainability: reducing agrochemical use. While soilless systems have presented themselves as one of several alternatives to fumigation, this option is particularly fraught for California strawberry growers, who farm on land that is highly suitable for strawberries, with soil providing clear competitive advantages. Yet this same soil is rife with diseases that cause significant harm to strawberry plants, providing the rationale for continued fumigation. Unfortunately, virtually all remaining alternatives to fumigation contain equally confounding trade-offs.


Today’s California strawberry industry, which grows 88 percent of US strawberries, was born in the 1860s in the Pajaro Valley, straddling Santa Cruz and Monterey counties.7 There, apple orchardists experimented with planting strawberries in the rows between trees. Once they began shipping the fruit to San Francisco markets, they found strawberries to be quite lucrative.8 Land in the Pajaro Valley was ideal for strawberry production, especially in the alluvial plains where the rivers meet the seas. The sandy loam soils drained well to prevent the build-up of moisture and salt and protect a fruit that is prone to rot.9 The Mediterranean climate was no less accommodating. With the vast majority of rain falling between November and April, the warm and dry temperatures of summer protected against molds and other moisture-generated pests and diseases during the harvest season. The natural air conditioning of the Pacific Ocean was an additional advantage, in the summer bringing cool, moist air into the low-lying coastal areas, while in the wintertime keeping frosts at bay. The benefits of what some call the “eternal spring” included a long harvest season, eventually inducing breeders to develop varietals that could be harvested nearly year-round.

Such advantages also brought problems, however, as growers were eager to maximize the use of this land. Soon into the industry’s rise in the 1920s, growers began to encounter several soil-borne diseases that caused plants to wilt, yellow, and often die. Enrolling scientists at the University of California to remedy the blight, they learned that the fungus Verticillium dahliae, a widespread crop plant pathogen, was responsible for wilt and often death.10 The fungus fed on nutrients oozing out of the plant’s roots and eventually clogged its vascular tissues. Worse, Verticillium left its sclerotia (the hard remains) in the soil, where it remained for years waiting to colonize a new host. University scientists tried a variety of tactics to thwart the fungus, but it wasn’t until the late 1950s that they landed on a solution that seemed to fix the problem once and for all: fumigation with a synergistic combination of the former fire retardant methyl bromide and the former wartime tear gas chloropicrin. By the early 1960s, growers had widely adopted a combination of these chemicals. Just as breeding had extended the seasons of strawberry production, fumigation allowed for the intensification of strawberry production. Now strawberries could be planted on the same blocks year after year, avoiding the need for rotations.11 Production expanded into other coastal areas, and productivity skyrocketed. Between 1960 and 2014, acreage more than tripled, production increased tenfold, and the value of production in real dollars increased by 424 percent in Monterey and 593 percent in Santa Cruz counties alone, the first centers of strawberry production.12 Such growth came at a cost, however: the highest chemical load of any crop produced within the state.13

As chemicals designed to penetrate soil and much else, fumigants were particularly noxious for those in surrounding communities, a problem that would eventually lead to greater scrutiny of their application. Yet it was methyl bromide’s ability to reach the upper atmosphere that first thwarted fumigant use. Methyl bromide met its demise in the form of the international Montreal Protocol on Substances that Deplete the Ozone Layer of 1987. After much delay (thanks to the efforts of the US government to protect the strawberry industry), methyl bromide’s allowable uses dwindled, and in 2016, it was finally phased out altogether, save use in nurseries.14

Chloropicrin began to see tighter use restrictions, too, and in 2013, the makers of the highly toxic methyl iodide (meant to substitute for methyl bromide) withdrew that chemical from the market, following activist protests and a lawsuit disputing its registration as an allowable chemical.15 In a 2013 action plan for the development of practical and cost-effective ways to grow strawberries without soil fumigants, California’s Department of Pesticide Regulation hinted that the chemicals might be regulated away altogether.16

Adding to the industry’s challenges, since 2005, two so-called novel pathogens have appeared in California strawberry fields, which, like V. dahliae, cause strawberry plants to wilt and die.17 Although most industry observers attribute this new blight to the loss of methyl bromide, some have suggested that years of fumigation are to blame. In contributing to the simplification of soil biota, they argue, fumigation has made the soil more prone to disease. In either case, the potential of widespread soil disease harbored in otherwise ideal land poses a serious threat to a California strawberry industry that finds itself with ever fewer chemical combatants at its disposal and prohibitive economic conditions for restoring naturally suppressive soils.


The unfortunate convergence of increased soil disease and a changing regulatory climate for the agrochemicals that have controlled such disease has created the context for the California strawberry industry — an industry that is in part the product of the soil conditions that preceded it — to experiment with soilless systems for the first time. Soilless indoor “container” production is widely used in Europe, where strawberry growers complied with the phase-out deadlines for methyl bromide earlier than US growers. California growers, in an attempt to avoid the substance that is the ostensible source of disease but otherwise draw on their enduring advantages, have instead opted primarily for a less transformative approach, what some call “field-scale hydroponics.” This tack involves cutting troughs into traditional strawberry beds, lining them with landscape fabric, and filling them with a substrate material such as peat moss, coconut coir, or mixtures of these and other materials.18

Recorded experiments have shown that field-scale hydroponics has near-equivalent yields to fumigated soil.19 However, at least according to some growers, the quality of the strawberry suffers greatly in such systems, where both sweetness and firmness go missing. One grower I spoke with had experimented with adding different nutrient levels to the soil but remained disappointed. The problem may well lie in a reductionist approach to soil nutrition that the Real Organic Project and other advocates of sustainability founded in lively and biodiverse soil critique.20 Soil has synergetic qualities that are neither quantifiable nor extractable, such groups argue, so adding back “essential” nutrients misses the point.21

Nevertheless, the quality of the strawberry and attachment to notions of a living soil are not the primary reasons that most California strawberry growers are reluctant to move forward with soilless systems. After all, the strawberry industry has consistently chosen volume and shippability over taste in their breeding priorities. Instead, growers are worried about a wholesale shift to indoor farming. For one, these systems call for major capital investments in infrastructure for buildings, trays, and automated systems to deliver the daily nutrition and irrigation requirements for plants with shallow roots.22 Widespread adoption of systems that double or treble per-acre investments would doubtless render the cost of strawberries out of reach for many consumers. More significantly, indoor growing would eliminate the California industry’s most central competitive advantage — its location on the sandy-soiled, temperate coast. With a shift to indoor production raising the price of berries, there would be little to prevent people from setting up greenhouse operations much closer to urban markets in the Midwest and East, putting many California farmers out of business.

Growers have reason to be fearful. As early as 2011, an estimated 184 greenhouses had cropped up in a five-county area of northwest New Jersey.23 One company, Plenty, has announced plans to build a major indoor farm next to every major city in the world.24 Even in California, in 2017 an estimated 300–400 acres of strawberries out of 34,000 in the state were grown in high-tech greenhouses.25 Windset Farms, a Canadian company that operates some of these facilities, has even built a major greenhouse complex in Santa Maria, ironically, one of the premier growing regions for outdoor conditions. Initially developed for growing tomatoes year-round, the complex has recently expanded into strawberry production for that same purpose.26 Windset’s own proprietary varietal, the “Soprano,” reputedly does well in soilless substrate.

Promoters of indoor farming emphasize their proximity to urban markets, suggesting that such operations reduce food miles and, hence, energy use and greenhouse gas emissions. As put by the Plenty website, “We build our farms next to where people live, so our produce is grown a short drive from your local store.”27 As for Windset Farms, according to one source, they chose this region for the availability of nearby aquifer water, labor, flat land, and greenhouse services as well as its location “within four hours of tens of millions of consumers.”28 In adding the challenging strawberry to their product line in the middle of strawberry country, one can only speculate that they also wish to gain competitive advantage in the race among “progressive” companies to farm strawberries without chemical fumigants.

Yet these approaches to sustainability are not without their trade-offs. Studies using life-cycle analysis suggest that transportation contributes far fewer greenhouse gases than on-farm production.29 Indoor farming systems also involve massive amounts of materials, not all of which are easily disposed of or recycled: irrigation pipes, plastic linings, even Styrofoam containers. They are energy intensive, as well, requiring year-round lighting and temperature controls. Even field-based soilless systems are resource intensive. The substrate used to substitute for soil is costly and not limitless. Experiments have used peat moss from Canada and coconut coir from Sri Lanka. The impact of importing materials from elsewhere, some of which would eventually have to be produced and not just extracted, to create an ostensibly more sustainable system in California is not negligible. Moreover, given the necessity of using automated systems to apply water and nutrients, these are energy-intensive operations, too — more so than the average farm producing the same volume of strawberries.30


Soilless systems are not the only option on the table for California strawberry growers seeking to reduce the use of highly toxic fumigants for managing soil-borne pests. Like soilless systems, several options are allowable under current organic standards, as long as such standards are adhered to across the rest of the production system. However, those that have shown any efficacy in California present profound environmental (and social) trade-offs as well.

Options involving nonchemical means of soil disinfestation tend to be resource intensive, too. Steam treatment, for instance, applies machine-generated heat to kill soil-borne organisms. Because steam must be applied to a given patch for several minutes to be effective, only a small part of the field can be treated in a day. Not only is the machinery very expensive, but the technology relies on large amounts of water and fossil fuels — resources that are neither cheap nor plentiful in California and whose heavy use in agriculture is already subject to much controversy.31

Another method, anaerobic soil disinfestation (ASD), is attracting a great deal of attention these days. ASD involves creating anaerobic (oxygen-free) soil conditions by adding a major carbon source, such as rice bran or molasses, to fields and then flooding them with water. In addition to depriving pests of oxygen, ASD volatilizes organic compounds that are already present in the soil and are toxic to microorganisms.32 Yet it is uncertain whether ASD could ever serve as a widespread solution, given the limited availability of carbon sources within the region and its profound dependence on California’s ever more precious water. So far, those experimenting with ASD generally import rice bran from the northern Central Valley, where rice is extensively grown; however, with wide adoption, those sources would not suffice. Extending water-intensive rice production to meet the needs of strawberry growers would be ironic, as would be encouraging white rice consumption in order to save the bran for strawberry production. ASD also requires large amounts of plastic tarping. In any case, thus far the results for ASD have been mixed in terms of controlling pathogens and weeds. And while growers remain interested in ASD because of its potential to allow them to continue growing strawberries on the same block, year after year, few have taken it to scale.33

As it happens, the most efficacious way to grow strawberries without fumigants is with agroecological methods — those that do not so much disinfest the soil as feed it, in keeping with original organic principles. Successful techniques include cover cropping, composting, and applying brassica seed meals or other antimicrobial crop residues to the fields. Rotations of broccoli, which has mild fumigation properties, have proven particularly effective.34 But these methods are most effective when strawberries are planted on the same block only every four or five years, making them a minor crop within highly diversified cropping systems. Such an approach is therefore unsuited to producing fruit for a national market 12 months of the year (if you include the short season in Mexico), year in and year out. The approach is also challenging economically because of the high land values that predominate in California’s strawberry-growing regions; revenues from broccoli (much less fallows) are generally insufficient to pay those high land prices. Growers who successfully employ this approach are able to obtain high price premiums for strawberries since they generally sell in farmers’ markets or other venues where consumers are willing to pay — and to purchase the crops growers rotate with strawberries. But those markets are limited. Thus the most efficacious approach to eliminating fumigants rests on an entirely different model than the strawberry industry is accustomed to, and, given shortages of prime strawberry land, cannot supply the amount of strawberries the market currently bears.

Market conditions aside, even this approach entails sustainability trade-offs. Most growers that employ these methods use ample amounts of plastic mulch for weed control, and they must make further compromises owing to the absence of fumigant-free plant starts. The strawberry nurseries that supply these starts have thus far been exempt from the methyl bromide ban because California’s Clean Strawberry Plant Program requires certification that plants are disease free. Even certified organic fruit growers are exempt from requirements to obtain organic starts since they are nowhere available. And the use of methyl bromide and chloropicrin in the nurseries is not negligible, given the nature of the propagation business. Starting from meristems, nurseries propagate clones of cultivars in a process that spans three to four years. Some of this propagation takes place indoors in screen houses, using plastic containers and climate controls — much like soilless systems. But the latter phases of plant propagation require a good deal of spatially separated land.

The nurseries are not heedless of the possibility that they, too, will see tighter restrictions on chemical fumigants and so they, too, are experimenting with alternatives. With the near-zero tolerance for diseased plants required by the clean plant program, they cannot afford to invest in solutions that are not highly effective. Although plant nurseries are experimenting with steam, use of soilless substrate is the more likely direction, especially because so much of their production already takes place in highly controlled conditions. While adopting such systems will ensure that fumigant use is discontinued throughout organic systems (and possibly conventional ones as well), by other measures of sustainability, the plant propagation business will continue to fall short.


Currently, strawberries cost more than $70,000 per acre to grow — a sizable investment.35 Virtually all alternatives to chemical fumigation will raise these costs by orders of magnitude. I’ve been told that were nursery growers to use soilless systems for all four years of plant propagation, the plants alone could cost fruit growers up to $20,000 per acre, saying nothing of what the costs would be for in-field hydroponics in fruit production. The argument that more-intensive methods keep prices down for consumers doesn’t hold for strawberries unless such methods include the continued use of highly toxic chemical fumigants. Even then, with methyl bromide already off the table by dint of an international treaty and others losing efficacy against novel pathogens, a nonfumigant (and more costly) future may be inevitable.

In that context, I do not think that soilless systems can be categorically dismissed. Not only can hydroponics reduce pesticide use, but they also offer the possibility of improving working conditions. Soilless substrate can be put in waist-high trays, eliminating the need for workers to harvest strawberries while uncomfortably bent over. But we should not fool ourselves that soilless systems are any less resource intensive than soil-based systems, especially when the materials used are extracted from ecosystems elsewhere. Practically speaking, a major shift to soilless production would put many California growers out of business, many of whom already carry significant debt in order to avail themselves of outdoor conditions so hospitable to strawberry production. Few would pay for such costly land and forgo the advantages it bestows by growing indoors.

Unfortunately, other methods of soil disinfestation entail similar environmental trade-offs, reliant as they are on plastics, water, and fossil fuels, although perhaps not to the same degree. Through that lens, agroecological techniques are the least resource intensive, except that they require more land to incorporate their rotations. However, good strawberry land that can produce strawberries nearly year-round is not infinitely available, and what exists is very costly. Converting wholesale to an agroecological strawberry production system would almost surely involve major reductions in the production of strawberries, putting additional pressure on prices. In short, there are simply no options for farming without fumigants without significant sustainability trade-offs — as well as major increases in the costs of production and potential loss of livelihoods.

I have long held that we must find ways to transform the vast majority of agriculture for the many rather than build perfect systems for the few. For that reason, I remain skeptical of marketing systems that depend on well-off consumers paying for more-perfect forms of production. Rather, we need to find other ways to provide financial support for food producers who are attempting to lessen their environmental impacts on a broad scale. And yet, the strawberry case illustrates that sustainability itself is not a singular goal that can be achieved all at once. Instead, striving for sustainability in agriculture presents inescapable trade-offs in the use of resources and materials, not to mention social goals around working conditions, farmer livelihoods, and affordability. It’s time we started having a public conversation about the fact that those trade-offs exist and how we want to navigate them.


Research contained in this article was funded by the National Science Foundation (Award no. 1262064).

Read more from Breakthrough Journal, No. 9

Featuring pieces by Rachel Laudan, Alan Levinovitz,
R. David Simpson, Mark Sagoff, Fred Block,
Brandon Keim, and more.


[1] Tom Karst, “Updated: Organic Board: Aeroponics Out, Hydroponics, Aquaponics In,” November 2, 2017, The Packer,

[2] Emma Cosgrove, “AgriFood Tech Investment Surges to $10.1bn Bringing in a New Normal,” March 8, 2018, AgFunderNews,

[3] Sir Albert Howard, The Soil and Health: A Study of Organic Agriculture (Clark Lectures) (Lexington: University Press of Kentucky, 2007); Northeast Organic Farming Association of Vermont, “Keeping the Soil in Organic,” video, October 14, 2017,

[4] Real Organic Project,

[5] Julie Guthman, Agrarian Dreams: The Paradox of Organic Farming in California, 2nd ed. (Berkeley: University of California Press, 2014).

[6] California Department of Food and Agriculture, “California Agricultural Production Statistics: 2016 Crop Year Report,”

[7] California Strawberry Commission, “California Strawberry Farming” (January 2018), Reports/Industry Fact Sheets/California Strawberry Farming Fact Sheet 2018.pdf?ver=2018-03-08-115600-790.

[8] Stephen Wilhelm and James E. Sagen, A History of the Strawberry: From Ancient Gardens to Modern Markets (Berkeley: University of California Press, 1974).

[9] Miriam Wells, Strawberry Fields: Politics, Class, and Work in California Agriculture (Ithaca: Cornell University Press, 1996).

[10] Wilhelm and Sagen, A History of the Strawberry.

[11] Stephen Wilhelm and Albert O. Paulus, “How Soil Fumigation Benefits the California Strawberry Industry,” Plant Disease 64, no. 3 (1980): 264–70.

[12] Laura Tourte, et al., “The Evolving Fresh Market Berry Industry in Santa Cruz and Monterey Counties,” California Agriculture 70, no. 3 (2016): 108.

[13] Susan E. Kegley, et al., Hooked on Poison: Pesticide Use in California, 1991–1998 (San Francisco: Pesticide Action Network, 2000).

[14] Brian J. Gareau, “Dangerous Holes in Global Environmental Governance: The Roles of Neoliberal Discourse, Science, and California Agriculture in the Montreal Protocol,” Antipode 40, no. 1 (2008): 102–30.

[15] Julie Guthman and Sandy Brown, “Midas’ Not-So-Golden Touch: On the Demise of Methyl Iodide as a Soil Fumigant in California,” Journal of Environmental Policy and Planning 18, no. 3 (2016): 324–41.

[16] California Department of Pesticide Regulation, Nonfumigant Strawberry Production Working Group Action Plan (April 2013), 1–34,

[17] Steven T. Koike, et al., “Recent Developments on Strawberry Plant Collapse Problems in California Caused by Fusarium and Macrophomina,” International Journal of Fruit Science 13, no. 1–2 (2013): 76–83.

[18] California Department of Pesticide Regulation, Nonfumigant Strawberry Production.

[19] Ibid., p. 29.

[20] Northeast Organic Farming Association of Vermont, “Keeping the Soil in Organic.”

[21] Maria Puig de la Bellacasa, “Making Time for Soil: Technoscientific Futurity and the Pace of Care,” Social Studies of Science 45, no. 5 (2015): 691–716.

[22] California Department of Pesticide Regulation, Nonfumigant Strawberry Production, 12.

[23] Glenn Collins, “Greenhouse Projects Nurture Produce and Workers,” New York Times, March 1, 2011,

[24] David Roberts, “This Company Wants to Build a Giant Indoor Farm Next to Every Major City in the World: Vertical Farming May Finally Be Growing Up,” Vox, updated April 11, 2018,

[25] California Strawberry Commission, interview with the author, June 2017.

[26] The Packer, “Greenhouse Production Expands in California,” May 24, 2013,

[27] Plenty Unlimited, Inc., “Food With Purpose,”

[28] The Packer, “Windset Farms to Double Santa Maria Acreage,” April 12, 2013,

[29] Christopher L. Weber and H. Scott Matthews, “Food-Miles and the Relative Climate Impacts of Food Choices in the United States,” Environmental Science & Technology 42, no. 10 (2008): 3508–13,

[30] California Department of Pesticide Regulation, Nonfumigant Strawberry Production, 28.

[31] California Strawberry Commission, “Investing in a Sustainable Future,” (January 2013); California Department of Pesticide Regulation, Ibid.

[32] Amanda Hodson and Edwin E. Lewis, “Managing for Soil Health Can Suppress Pests,” California Agriculture 70, no. 3 (2016), 137–41.

[33] Carol Shennan, et al., “Anaerobic Soil Disinfestation for Soil Borne Disease Control in Strawberry and Vegetable Systems: Current Knowledge and Future Directions,” Acta Horticulturae 1044 (2014): 165–75; Joji Muramoto, et al., “Effect of Anaerobic Soil Disinfestation and Mustard Seed Meal for Control of Charcoal Rot in California Strawberries,” International Journal of Fruit Science 16, Suppl 1 (2016): 59–70; California Strawberry Commission, “Investing in a Sustainable Future”; California Department of Pesticide Regulation, Nonfumigant Strawberry Production.

[34] Eric Brennan, USDA research horticulturalist, personal communication.

[35] Mark P. Bolda, et al., Sample Costs to Produce and Harvest Strawberries: Central Coast Region, University of California Cooperative Extension and Agricultural Issues Center (2016), 1–20, Note that these data are now two years old.



Julie Guthman is a professor of social sciences at the University of California, Santa Cruz, and author of a forthcoming book on the California strawberry industry, to be published with the University of California Press.









With the Grain
by Rachel Laudan


On Naturalness
by Alan Levinovitz


The Trouble with Ecosystem Services
by R. David Simpson


Welcome to the Narcisscene
by Mark Sagoff


Seeing the State
by Fred Block


If We Could Talk to the Animals
by Brandon Keim


Read more from Issue 9 . . .