I recently had dinner with my long time farmer friend Chris Yoder of Van Garden CSA in Dover, MA. We were talking about lab-produced meats and the recent explosion of vertical farming in the Boston area, and how ridiculous these “sustainable” solutions are. He told me his brother came up with a slogan: “Freight Farms: Your Salad in Critical Care”. What a great visual – all that plastic, outside inputs, no soil, climate control, monitors… I completely agree.
Technology definitely has it’s place in the future of our food, but I’ve been seeing more and more “solutions” that don’t seem to make a ton of practical sense. Huge infusions of tech dollars are being poured into food production systems that seem to be working against nature instead of with it. Lab-produced meats are a perfect example of this. Instead of using cattle to graze land we can’t crop, converting grass to nutrient dense protein, many seem to feel that it’s more sustainable to take mono-crop soy and convert this to fake, “bleeding” meat through a resource-intensive process.
The same holds true for these new shipping container “sustainable” salad factories and other 100% artificial light plant factories. Now don’t get me wrong, there could be a place for greenhouse-produced greens in certain areas that get a lot of sunlight for passive solar energy. I even think some forms of indoor agriculture that utilize natural sunlight and fish could be a potential solution in some areas. But let’s think about these 100% artificial light salad production facilities for a minute and compare them to greens grown outdoors.
On a farm that incorporates animals and uses soil to grow crops organically, there’s little need for mined minerals, fertilizers, artificial lights, steel racks, and the energy required to heat the building. With smart use of crop rotations, cover crops and green manure, compost and animal inputs, the soil has all it needs to produce healthy crops. The sun provides the energy for free.
It fascinates me that there isn’t even a sunroof on these $85,000 “sustainable” solutions to our salad fix. On a perfectly sunny day, these containers are still sucking energy to grow lettuce, all in an effort to reduce food miles and take up less land than traditional farming. But at what cost? Do the inputs required to grow these greens really result in a more sustainable product? Has anyone done a life cycle assessment on these compared to supporting local sustainable producers?
It turns out there actually has been studies on the thermodynamics of these methods using 100% artificial lights, and guess what? They make no sense at all. One study found, “Vertically grown produce has a carbon footprint that is much higher than conventionally grown produce”
Researchers that looked at artificially lit greens farming found that the energy required just for lights alone is one to two orders of magnitude greater than the energy content of the plants. This didn’t even account for the energy loss required to make the artificial lights to begin with, nor the energy required for the building, the trays, racks, etc.
One researcher commented: “Why does it make sense to put a lot of intellectual activity and resources into something that negates the direct use of our one and only absolutely renewable resource – the sun – and totally replace it with artificial light?”
When compared to shipped in lettuce, the 100% artificially lit lettuce lost big time. A 2008 study from Cornell University found the following:
Production system kg CO2/kg lettuce
Import average of 2900 miles 0.70 (transport only)
100% Artificial Lighting 3.95 (lighting only)
70% Sun/30% Artificial Light, Ithica, NY 0.71 (lighting only)
70% Sun/30% Artificial Light, Long Island 0.35 (lighting only)
And remember, this is just looking at transportation of the lettuce to lighting only. The total costs of a 100% artificially lit salad growing system are higher than just lighting. But what about the winter, when we’re covered in snow? Certainly container farms are better than shipping in greens from far away, right?
However, when you look at the numbers, this isn’t the case. Passive solar greenhouses can produce lots of greens with very little energy input. A 2014 study on lettuce production carbon footprint showed unheated hoop houses (see photo below from study) in January at Michigan State University generated about one-fifth the CO2 compared to shipping in lettuce from 2,200 miles away. Results were 0.198 vs. 0.857 kg/CO2/kg lettuce.
What if we power the 100% artificial light with solar power? Wouldn’t that be better?
It turns out it would take about 4.5 acres of solar cells for every one acre of plant growth space. Just think for a moment of all of the raw materials and energy required to produce a solar cell. Since we can use the sun DIRECTLY to grow lettuce, it seems like a better use of solar cells would be to power things that we actually need energy for, like lighting for our homes. It seems to me that if we just cut off the tops of these vertical farm units and let the sun shine in, we might have a better return on investment.
Michael W. Hamm: C.S. Mott Professor of Sustainable Agriculture – Michigan State University and Director of the MSU Center for Regional Food Systems. said this in a post about the absurdity of vertical farming: “I take strong issue with those who go to great lengths trying to convince everyone this (vertical farming) is the solution to world hunger, fresh water challenges, and agriculture’s contribution to climate change.”
As a dietitian, I also have to point out something pretty serious here. Let’s also not forget what lettuce gives us, nutritionally. Not much. Lettuce is basically crunchy water. We’re spending so much of our investment dollars and intellectual energy on something that has the nutrition of a Kleenex. Salad is great at filling you up, but the health benefits are in what you put ON the salad (the nuts, the vegetables, the avocado, the steak tips…) not the lettuce. The lettuce just provides low-calorie volume to help us feel more full.
Lettuce provides “vitamin A” according to the USDA nutrient database, but it’s actually not true vitamin A. The plant form must be converted to vitamin A in our bodies. It takes about 10 to 28 molecules of carotenoids in plants to make one molecule of vitamin A. Efficiency of this conversion is influenced by several factors including the type food, the overall fat content of the meal, and the cooking method. About 45% of the population have a genetic factor limiting their ability to convert vitamin A from plant sources into active vitamin A. Vitamin A from animal sources is very effectively absorbed, with 100% absorption. Lettuce also contains a good amount of vitamin K, however it’s in the form of K1, found primarily in green leafy vegetables and plant oils, and bioavailability from plants is relatively low and depends on chlorophyll content. For vitamins A and K, your best source is not lettuce.
To me, a smarter investment in the future of our food would be these passive solar hoop houses with minimal-to-no artificial light and other off-farm inputs.
And while I’m at it, I’d like to propose that instead of lab meats, we could alternatively invest in more locally produced, well-managed grass-fed meat. Cattle, sheep and goats do very well in the New England landscape. Because of our high quality pastures, we can actually produce a lot more meat per acre than many other parts of the United States. They can graze hilly, rocky land that we can’t use for crops. These animals don’t require grain, so they don’t have to compete with us for farmland (which we can then grow lettuce and other vegetables on, using the sun!) Better yet, the impact of ruminants in a well-managed system actually improves the land. Their chomping, stomping and manure is required for healthy pastures, which sequesters carbon instead of emitting it. And remember, meat provides much more nutrition than lettuce.
All of this excitement surrounding high tech food solutions needs to be analyzed on a thermodynamic basis. We need to systems thinking, not linear, reductionist solutions. How can we maximize the energy from the sun? On a planet of limited resources, do we want to be using more artificial lighting and mined minerals to produce lettuce, a nutrient poor food with a big carbon footprint? Do we want to use more fossil fuels to produce more soil-depleting, mono-crop soy and then use it to make fake meat that bleeds just like the real thing, or just eat the real thing, raised the right way? These sexy “sustainable” high tech food solutions are doing nothing to ensure we’ll be able to produce food in 100 years. Our future depends on healthy soil, not lab meats and vertical farming.
As we look to new food solutions, I wish people would use a little more common sense and ask the basic questions, “Does this maximize solar capture? Is this system working with nature or against it?”