How Sustainable is Food from a Hydroponic Garden?

lettuce grown in a hydroponic garden

I first started thinking about this particular question when I wrote about the Brightfarms concept in mid-2011. No doubt, food grown on-site has a lot to recommend it: no energy used for transportation or refrigeration, and you couldn’t ask for fresher produce. But, after reading about Vancouver’s new “Living Produce Aisle” store, which opened earlier this month, I began to wonder – again – if this concept, which is definitely “local,” is truly sustainable?

The big question here involves energy use. Plants, regardless of how they’re grown, need light. If that light doesn’t come directly from the sun, it has to be provided through artificial means. The Brightfarms model uses natural light (though I wouldn’t be surprised if its supplemented by artificial light); the Living Produce Aisle, however, makes use of self-contained hydroponic cultivation units… so all light is artificial. In both cases, of course, water and nutrients have to be pumped to the plants, requiring more energy. Yes, you could do this with renewable energy; I see no indication that this is what’s really happening in either case, though. You could also use super-efficient lighting like LEDs (which may be happening here).

The other question that comes to mind is the range of produce that can be grown in a given hydroponic setting. Brightfarms can grow almost anything that’s not a root vegetable (which you can’t ever do hydroponically); they don’t bother with staple grains as they couldn’t compete on price. The Living Produce Aisle concept is limited to herbs, micro-greens, and sprouts. Yes, this produce can be grown quickly – up to four crops a month in some cases, according to owner Tarren Wolfe – but at what cost? The numbers in the The Vancouver Sun‘s blog post give us an indication: the 2000 square foot store can grow between 1000 and 2000 pounds of food a month, and Wolfe projects earnings of $50,000 a month. Yes, they’re serving smoothies and other value-added items, but that still strikes me as really large earnings for herbs and greens… which leads me to believe that the costs of producing them is pretty high, also.

Am I just not seeing other benefits? Or am I right in thinking that the Living Produce Aisle concept creates a “local” product that’s stripped of many of the advantages of its local-ness? Let us know what you think.

via Permaculture at reddit

Image credit: Lori Greig via photopin cc

  1. Christine Esposito

    Good questions and points, Jeff. Ones that need to be raised, as much as we sometimes would rather not. One project that solves the energy question is The Plant, here in Chicago, which you’ve aptly written about. An anaerobic digester running off of waste generated at the facility will enable this vertical farm to be off-the-grid.

    1. Jeff McIntire-Strasburg

      Thanks for chiming in, Christine! The Plant’s a very good example of how this kind of agriculture could be much more sustainable. If I remember right, they also use aquaponics, which also strikes me as a more sustainable option.

  2. Doodlemaier

    It’s probably still more cost effective to produce what they can hydroponically from on-grid electricity than from inputs and transportation costs derived in fossil fuels and, at least, the infrastructure is in place for when they decide on a system for generating their electricity locally. At least, that’s where my head would be if I owned either of these businesses. It seems to me to be a step in the right direction. . .

  3. Jason Hirst

    There is some great data available in the presentations from the Challenges in Vertical Farming workshop that took place last month. http://challengesinverticalfarming.org/.
    With controlled environments you can measure the inputs and outputs with great precision and you can see that in the data. If think the problem comes when you want to compare this with conventional approaches where the data will be much more patchy.

    You’re right that lighting efficiency is the key to sustainable indoor growing. In Ray Wheeler’s presentation (same source above) there is a nice table showing conversion efficiency of different light sources. Fluorescent tubes are about 20% efficient. Horticultural LEDs are already > 40%, but they are improving very fast. 10 years ago they were <10%. In the next 3 years they are expected to exceed 60%, and it will carry on. See http://en.wikipedia.org/wiki/Haitz's_law

  4. Tarren Wolfe

    Hi Jeff – It’s Tarren Wolfe here, founder of Urban Cultivator. First of all, kudos to everything you do on this blog and your efforts in making this world a more sustainable place to live. I wanted to respond to your questions about Urban Cultivator and the Living Produce Aisle – specifically when it comes to energy use.
    When thinking of the local movement we must consider what truly goes into bringing food to your table. The gas to run tractors, the energy it takes to a run a farm and then the gas it takes to bring that food to your grocer, especially when food need to be shipped in refrigerator trucks. By the time the food gets where it needs to be, a lot of energy has been consumed.
    Remarkably, food travel accounts for approx. 15% of energy use in the US ([ http://www.postcarbon.org/article/273686-beyond-food-miles ]. We all know food typically travels great distances to get to your local grocers but by growing it ourselves at the LPA, we’re helping to lower this number.
    The pumps inside an Urban Cultivator Commercial model – which is used in the LPA – runs for only five minutes every 3-5 days making energy consumption quite minimal. In addition, the Urban Cultivator Home model (the model available for your kitchen), uses 91 watts at 126 hours per week, which is 208 KWH per year – that’s less energy than a microwave. We’re currently working on energy consumption comparisons with University of British Columbia and I’m happy to share the results from that study with you once it becomes available.
    In terms of cost for production, 250 lbs of herbs and micro-greens can be harvested per year in one Commercial unit and you’re looking at .05 cents per pound for energy costs – add soil and seed, you’re looking at only $2 – $3 per lb. And living greens usually means double the nutrient value of pre-cut greens – there’s a lot of added benefit there!
    When it comes to lighting, we use T5 Fluorescent Lighting Technology. T5 adaptor technology is an alternative technology that replaces old inefficient lighting and is an energy-efficient measure to cut energy use in lighting by more than 65%.  [ http://saveiteasy.co.uk/index.php/how-it-workst5-tubes/energy-saving-tables/ ]
    One of the hardest things about maintaining a garden in many regions is the vast change in the weather. Urban Cultivator allows you to control your growing environment. Harsh climates can spoil crops in an instant – along with all the gas and traditional power used to grow those crops. Some regions also require more water usage than other areas but with Urban Cultivator, the environment is regulated and requires the same amount of water regardless of location.
    Urban Cultivator efficiently grows greens and herbs 365 days a year while efficiently reducing the amount of energy used to grow them! I hope this helps answer some of your questions, Jeff. Please feel free to email or call me to discuss this further at – [email protected] or toll-free at 1-877-352-0490 ext. 101

  5. simon

    This is part of an Article I did: If there is an alternative to growing food in soil, such as hydroponic gardening, it only makes sense to get the food we eat out of the soil if there is any danger of unknown pollutants in it. Even when soil is tested and found to be free from any of the well-known toxins, benzene or another poison could occur at any time after that. Also, there may be other toxic chemicals in the ground that are not known to cause health problems at this stage of human development. The answer to the problem of soil pollution is to use hydroponically grown foods, which are foods grown without soil, whenever possible.

    The safest way to grow the food we eat is through hydroponics. A growing number of health conscious persons are eating only vegetables grown this way because of the health benefits associated with them. Filtered water can be used that is known to be pure and the necessary minerals needed to grow plants can be added. Not only is hydroponically grown food not put into the soil, but it usually requires no chemicals in growing. Many hydroponic foods are therefore organically grown without any toxic materials.

    Some people say that foods grown this way taste better as well. A study was conducted by Plant Research Technologies Incorporated in California which compared the nutritional value of hydroponically grown tomatoes and sweet peppers with those traditionally grown in soil. Plants that were hydroponically grown were found to have “a dramatic increase in vitamins and minerals in hydroponics, in some cases up to 50% higher in vitamin content.” REF, GO TO:http://www.newsonhealthcare.com/hydroponically-grown-plants/

  6. Mörður G.Ott.

    Well the article should not generalize about hydroponics because of 2 hydronic growers.
    I can use growlamps all year long and be sustainable, because of renewable energy sourses. I have grown plants for root harvesting in hydroponics (carrots and sweet potatoes).
    There is no issue about hydroponics being sustainable, there is an issue with those who claim to be sustainable but are not. It’s not the method it’s those who use it.

  7. Scott Cooney

    Great article Jeff, and great feedback everyone. I guess my thought is that if you can set it up so that it’s local, you can always get renewables, daylighting, etc., later, but if the farm is far away, you can never eliminate the transportation costs. Just my two cents…it’s always been my thought that we can’t make the perfect the enemy of the good. Start good, slowly get better. 🙂

  8. John Bradshaw

    As of now, I think Hydroponic farming is more sustainable than Traditional methods. Now Hydroponic farming needs light which obviously the sun can’t produce 24/7. The amount of fertile land available for farming is one thirds compared to our ancestors. LED lights are fast improving and like Jason Hurst rightly said it will improve further by leaps and bounds. Hydroponic farming is the clear winner here unless there is an alternate method discovered that does not make use of artificial light (highly impossible).

  9. Daniel

    What I feel is the chief value of organically certified hydroponic vegetables is that the plants receive all of their nutrients through a composted organically brewed “tea”. This “tea” is typically a mixture of compost, or worm castings, bat guano, seabird guano, a molasses (a food source for the microrganisms), added rock minerals for micro nutrients, and a form of added beneficial mico-organisms such as mycorrhizal fungi. This mix is blended into well oxygenated water that is constantly bubbling and moving. The water movement, through the addition of air into the water, as well as water pumped back into the hydroponic water reservoir allows the oxygen to become water soluable, beneficial to the plant. Additionally it is in this compost tea brewing process that nitrogen is reduced into a soluable state that allows the plant to absorb it. Hydroponic systems will deliver this mix from the its reservoir to the vegetable, and water not used by the plant is returned back to the reservoir in a closed loop system. The only water loss is through evaporation and plant transpiration. When a vegetable receives its three main nutrients (nitrogen, phosphorous and potassium) and also receives its remaining 14 micro nutrients, the plant is off to a very good start of remaining healthy. If it stays healthy, the less chance of a pest infestation. Healthy, well watered, well nourished plants thrive and get to market quicker.
    The one point not covered in this article is that most hydroponic systems usually do not require chemical pesticides. Organically certified hydroponic growers are not allowed to use them. Hydroponically grown and certified organic vegetables provides a safe food choice for us to eat.
    Additionally the cost of production on micro-greens is really low. Here are your expenses (1) You need seed, grow mat, grow tray (2) You need a tiny bit of water, (3) Light – you can grow them in the dark for the first few days, and then if you give them light, so yes, grow lights becomes a expense. (4) Clam shells, or other container or packaging to sell in the market……….but overall revenues earned in sales far exceed incurred expenses.

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