Trudy writes:

Perhaps Roy doesn’t appreciate your approach, but I find it to be interesting. Educators know that repetition helps the student.  Your style makes this podcast interesting to citizen scientists, gardeners and many others.  Personally, I find the informal dialogue to have a great balance between information which could be a bit dry, and discussion which has some humor to strike just the right note.  I have recommended this podcast to friends (RL & FB), family, and my favorite market which also has a farm and is looking to expand options to grow in an empty former grocery store.

Thank you both from a listener to all the TWIV related podcasts!


Naples, FL

Todd writes:

Hi Dr. Despommier and Dr. Racaniello,

Just listened to the first episode of Urban Agriculture, and really enjoyed it.  I’m a plant pathologist, and I agree with much of what you say about monocultures.  They certainly do have a lot of insect and disease issues.  Parasites are never far behind…  I look forward to catching up on the newer episodes, and learning about vertical farming.

I’ve been listening to TWIV and TWIM for a while, and they’re among my favorite podcasts.  I appreciate the evidence-based information, the topics are fascinating, and you all seem to have a good time.  Scientists are people, too 🙂  Anyway, I just wanted to thank you for all that you do, both professionally and with the podcasts, they’re great.

Best Regards,


Maryjo writes:

Hello! Discovered your podcast recently and really enjoy the topics and the expertise that you provide.

I listen to a wide variety of podcasts so if I may offer some very frank but well meant piece of feedback: you guys really ramble throughout the conversation. I think with some thoughtful editing the podcast could easily be 40 minutes long and still allow you to make all of the points you want to make.

If its possible for all comments that eventually make it to air to stay more closely aligned with the topic of the podcast it would allow for better listening experience.

So far in the episodes that I have listened to, I have done a lot of skimming through or fast forwarding.

Thanks for the opportunity to provide this feedback. Again I really appreciate the topics offered and the expertise your show offers. These comments are well meant and I look forward to continued success of your show!



Rachel writes:

Greetings Doctors!

Thank you so much for not just this podcast but TWiP as well. I wrote in to TWiP years ago when I first started by PhD and it, along with other MicrobeWorld podcasts, got me through countless nights of microscopy and blotting. I’m writing a few months after defending and  shows like yours helped remind me there is science going on outside of the GPCR trafficking I have been buried in.

On to what I actually wanted to share:

I recently spent some time in Uganda to teach at a girls science camp and found that even in the largest city, Kampala, food crops and animals are grown everywhere. Banana trees and maize plants fill many backyards, alleys and any other unclaimed land with sunlight. This goes the same for animals; cows, goats and chickens were present throughout the suburban areas. While this presents all sorts of health issues for both the plants/animals and the humans that go on to eat things grown in urban waste, I thought it was fascinating that in a young city in a developing nation the idea of having food grown far from the population is not assumed like it is here in the states. This seems like there should be great opportunities to develop urban ag in these sorts of cities before people start to think it strange to have crops near them. Do you know of any projects in Africa?

This podcast has focused on production of plants but I think production of insects for food could be another major branch of urban agriculture. Unlike cows, chickens and pigs insects are easy to keep in great numbers in very small rooms with minimal waste production. I think it would be awesome to have an episode where you interview one of the companies trying to get entomophagy going in America. I’ve attached a few relevant links below.

Have a fantastic day!

Robin writes:

Stephen Colbert calls out ‘I’m not a scientist’ Climate-change deniers

Check out this video on YouTube:

Megan writes:

Hello Professors,

I wanted to write to share this article about germ-less, soil-less, lettuce farming in a Toshiba factory in Japan. I thought the germ-less concept was interesting, although I’m sure you have heard of this before. The main reason this piqued my interest is because I came across this article on the front page of Reddit. I’m not sure if either of you know much about Reddit, but in case you don’t, being on the front page means that pretty much every computer programmer, software engineer, “techie” etc in American saw this (my husband is a software engineer, so I can confirm that). Just excited to see that Urban Ag is making it a little further into the mainstream.

Thanks for all of the knowledge you share.


Here is the link to the article and I have also attached a pdf copy as well.

Clyde writes:

Doctor Dickson and Doctor Vincent,

Have you seen the “Vertical Axis Wind Turbines” (VAWT Turbines) by “Pacwind” before?

They are more efficient than conventional wind turbines, and they would probably

look better, mounted on the roofs of buildings in the urban farmscape!

They also claim, that “VAWT” turbines don’t kill birds like conventional wind turbines

are said to do.

What are your thought regarding these cool wind turbines?

Thanks, Clyde

Todd writes:

Just a quick note to point out 2 indoor farms featured on Aljezzera America.

The use of red and blue LEDs as grow lights, and the hopes of tuning them for individual varieties, combined with the idea of combining them with an indoor fish farm in order to use the their nutrient rich waste water to fertilize the plants, really made me realize how much more viable vertical farming is today.

Several years ago, fluorescent lighting must have seemed leaps and bounds over incandescent lighting.

They claim a 98% recycling of water in one of these farms, I would have thought the plants would lose more than 2% through respiration!  Do they keep the humidity higher in these farms to mitigate this?

Thanks for all the podcasts!

Todd in northern Colorado.

Video here:

Story here:

Michael writes:

Dear Dickson and Vincent,

I wanted to to thank you both for a wonderful pod cast series! I always look forward to an email notification telling me when a new show is available.

I first came across vertical farming and urban agriculture just over a year ago and was so intrigued that at the age of 30, I quit my job in manufacturing and took up a full time traineeship in Production Horticulture. Since March I have had the pleasure of training at Chisholm Institute, a hi tech glasshouse located south of Melbourne Australia. The past 9 months has been a whirl wind experience securing a spot on a Nth American Study tour visiting 18 farms across Canada, Mexico and the U.S, with a visit to Lufa farms in Montreal being by far my favourite experience.

Your pod cast has been fantastic for a student like myself to keep up to date with all the latest technology and developments within the industry. Lets hope more young people decide to get involved in protected cropping and turn urban agriculture into a widespread reality.

Keep up the good work,


Thomas writes:

Dear Dr’s Vincent and Dickson,

In the 11 episodes you’ve produced, I haven’t heard anything about space conditioning and the energy sources or amounts that are required to keep the growing spaces at the appropriate temperatures. Energy for lights isn’t the only or even the biggest energy user you’re around.

This can play a large role in whether a building works and/or is affordable as well as the type of crops that would grow best depending on the time of the year.

Since many warehouse and factory buildings that may seem attractive for this type of operation were created without energy efficiency as key design elements, they can require substantial retrofits to make them work during seasonal extremes.

Another thought that I was hoping you would explore, is growing different types of crops depending on product availability and competition in the market, such as from traditional farms in the typical growing season.

It seems to me, that economically, it may make sense to shift to at least some “cash crops” during the harvest season of traditional farms, when prices tend to be lowest. Of course if you can convince the buyers to pay the same higher price you’re around, that may not be necessary.

I think the question of growing cash crops, such as herbs and spice type plants for culinary or cosmetic purposes, may be lucrative. This could help balance out the traditional summer harvest & keep the income revenue at high levels. These systems could of course be used year round for herb production for industries such as essential oils who need the highest quality products near their stills. Some herbs are so lucrative that it may allow a vertical farm operation to work where it might be too expensive otherwise.

I’m also very interested to see how we can scale a system for apartment dwellers where sunlight is at a premium as well a space. The health implications could be incredible for many on tight budgets who occupy these tiny units, as well as availability a great tasting, high nutrient food year round.

Thank you for reading and addressing my questions & ideas.



Jim writes:


Just wanted to pass on The Future of Agriculture? Indoor Farms Powered by LEDs that includes other links related to the topic.

Jim, Smithfield, VA

Jim writes:

Item from Boston I thought was you.

It’s a site called and concerns a city-wide change to promote all sorts of local growing efforts. Here’s the link.

Jim writes:

Here’s another interview.

Buried in this link to Dylan Ratigan’s blog is a link and comment about Archie’s Acres, a venture in California. This would give you some West Coast coverage.


Smithfield, VA

Joe writes:


I would like to suggest you do a show on and their constellation of resources for modern “Upstart Farmers” as they call us.

Dr. Nate Storey is a leader in the field and the thought leader I turn to  when my investors ask what research have you done in vertical farming.

I say, we use the technologies and educational resources of

I don’t know anyone else that I can turn to for practical tools and advice on creating a profitable business in the urban/vertical farming space.

They have an educational service called Upstart University (USU) that has a small monthly fee and are he finest educational resources available.

Thanks for everything you do !

Joe aka Farmer Joe

Robin writes:

A few musings on agriculture in general:

Coupled climate feedbacks will combine with irreversible, unstoppable food, water, soil and biodiversity loss that will start in 20 years. This cascading collapse is the biological version of 911 — the destruction of the crucial inner-underpinning supports of life itself on earth.

  1. In ten years we will all fight for food and water on a scale never imagined. In 20 years, unstoppable, irreversible mass extinction will start. Our renewable energy systems stop working as they reach the end of their life-cycle becoming garbage in a time of shortages. We will have no food, no water, no energy, no peace.
  2. It begins here:
  3. Right now, 1 billion people walk a mile each day for water.
  5. In 10 years 4 billion people will be without enough water.
  6. In 10 years 2 billion people will be severely short of water.
  8. Ground water depletion has gone critical in major agricultural centers worldwide.
  12. The world’s rivers and lakes are drying up.
  15. Drought is spreading across the earth.
  17. In 35 years over 2 billion people will move to cities.
  19. 75% of the infrastructure they require does not exist.
  21. We passed peak growth-rate for food production in 2006.
  23. In 60 years, human agriculture will stop because of soil loss and degradation.
  25. We add 1 million more people to earth every 5 days.
  27. We have to grow more food over the next 50 years than we grew in all of the last 10,000 years, combined.
  30. We will need 12 million acres of brand new farmland every year for 30 years to do it.
  31. We are losing 24 million acres of farmland every year.
  33. We will run out of easy access to 2 critical fertilizers.
  35. Our crop lands and pastures are to blame for 80% of all recent land vertebrate extinctions says Anthony Barnosky.
  37. In 20 years we will pass peak energy and minerals.
  39. This will happen when all our new solar panels and wind mills stop working and become expensive junk we can’t afford to replace or recycle in times of shortages in water, food, energy, minerals and civility.
  42. Lots of guns and no food, water or energy makes Johnny a bad bad boy.
  44. After all the violence, then the bad news starts.
  45. In 25 years earth will go into a planetary ecological state shift and enter into runaway, irreversible, unstoppable mass extinction.
  46. To aggravate matters, magnetic pole flip could expose vast areas of geography to radiation burning for hundreds of years.
  48. It ends here:

Clyde writes:

Dr’s Depommier and Racaniello,

Below is a weblink to Aleko, a wind turbine manufacturing company…

I guess PacWind must have gone out of business, so Aleko is another one of the alternative green energy companies that sell Vertical Axis Wind Turbines, abbreviated: VAWT’s.

I hope this helps your cause pertaining to self sufficiency, and promoting a green energy future with vertical farms, and self reliance, and not having to rely totally on the power grid!

Sincerely, Clyde

Shirish writes:

Can you please elaborate on the link and the differences.

I have loved your podcasts and am soon starting a business on urban farming. Choosing the technology and customisation to my climate is the main problem areas.



Kolkata. India

David writes:

Hello again Professors,

Thank you again for starting this podcast specifically about vertical farms. I find the intersection of agriculture, biology, and technology fascinating. Listening along to all you podcasts keeps me entertained and learning as I work in lab.

I had a question about the root supporting and nutrient solutions Dr. Despommier refers to frequently. I vaguely remember from my early biology classes that there are many bacteria in soil that form commensal or symbiotic relationships with the roots of plants, and that sterile soil can actually hurt plant growth. (Nitrogen fixing bacteria in the root nodules of legumes being the most classic example.) While the indoor growing industry seems focused on green, leafy vegetables, does the nutrient broth need to compensate for the lack of bacteria?

The weather is likely similar here as it is there, 26C and sunny. Hope you are enjoying it also. 🙂


Postdoc at NYU Medical Center

Robin writes:

Can urban agriculture be scaled up far enough fast enough without fossil fuel, mineral ore and rare earth inputs?

Len writes:


this is the place to do it

Shirish writes:


Thank you for all the episodes. I have decided to set up a commercial farm based on urban agriculture.

However a confusion between adoption of which technology.

At present it does not matter what the above technologies are relevant for. Would like to learn from an episode explaining in details

  1. Fixed costs
  2. Running costs
  3. Type of crops which is more suitable
  4.  Maintainence issues and down time 
  5. Organic what’s the difference between them as both ultimately produce chemicals as nutrients.


Shirish from India

Tom writes:

Hey guys,

I’m just getting started on a CEA closed-loop setup using aquaponics in northern Alberta and am looking for ways to support vertically stacked beds. Originally I was planning 3 stacked 12″ deep DWC’s,  using second hand painters scaffolding. But at 4’x8′ this works out to a lot of weight (about 800 kg each layer). So maybe shallow depth and micro greens is the only way I can vertically stack.

I am wondering what Dan used for his vertical support, (or if you guys know of any great links) and how much weight they hold? Is there somewhere I can purchase?

And what is the fantastic material he is using to seed the microgreens, it sure makes the process look easy.

Much appreciated and love the podcast.

Anthony writes:

Margaret Atwood essay:

David writes:

Vertical Farm on NPR!

“All Things Considered” folks will talk about some Vertical Farm thing in Newark today! I sure hope it’s aired just as I arrive home (to my driveway) after my typical Seattle commute. Surely, at least for a moment, I will be glued listening, thank you.

-from a long time TWIX advocate/addict whose daughter at Washington State University is currently de-chaffing her selections for graduate programs in virology, microbiology, and genetics (suggestions?).

FYI, all podcasts are archived forever via itunes and actively updated with BeyondPod (Android app).

Currently 13°C on a beautiful, partly sunny day here in Sammamish, WA.

With much appreciation,


Joseph writes:

Dear Urban Aggivangelists,

I’d like to invest in a vertical farm-centric company or subsidiary, both to promote the cause and hopefully to make a few bucks off the deal. But after researching public vertical farms, I could only come up with two: The Mirai Company (7931:JP on the NSE) out of Japan and Indoor Harvest (INQD on the NASDAQ) out of Texas. I don’t have a foreign trading account and Indoor Harvest hasn’t made any reproducible products or processes nearest I can tell.

So I’m not asking for investment advice obviously, but are you aware of other publicly traded vertical-farm centric companies or even mutual funds?

Thanks for the great show,


Vanderbilt University

Robin writes:

Thermodynamics of forest-driven biodiversity: Collapse

For those who think vertical farms and urban agriculture will significantly ameliorate climate change

Clyde writes:

Dr. Despommier,

Can beans of all kinds and other plants with proteins be easily grown and harvested in vertical farms of the future?

Thanks, Clyde

Peter writes:

Milano expo impressions

Dear Vincent and Dickson,

here are some pics of the US “vertical pavilion” at the Milanese Expo15 you mentioned in UA17, we happened to visit today. A 2nd email will include pics of the Israeli pavilion with a “vertical field”…

Best wishes to you,

Peter (of Wiesbaden/Germany)

…ciao, altra volta,


Sam writes:

Dear Dr Despommier and Dr Racaniello,

I am Sam Warren, a Civil and Architectural Engineering student at the University of Adelaide in South Australia. I am an avid listener of your UA podcast and a great fan of what you are doing. The emerging vertical farming industry excites me, and I intend to pursue a career in such a field post-graduation this year.

I and two of my fellow students have been working on a research project into vertical farming and urban agriculture from a Civil Architectural perspective. As South Australia shares a similar temperate climate to that of Southern California, extreme weather events such as droughts can severely impact crop production, which makes food security and water conservation large issues to tackle. Clearly, vertical farming has a place here.

However, we have run into a slight snag; wherein lies my question. We were initially looking to optimize a vertical farm of our own design in Adelaide, however the research component appears a little thin. We have been criticized for lacking an “engineering hook” – a fresh component of our research which makes it new and innovative, and not simply a report on what is happening with vertical farming elsewhere and why we should adopt it in Australia.

So, where should a budding group of engineering students with a structural background seek such a hook? What sort of research could you foresee being paramount in the development of vertical farming here in Australia and elsewhere, be it structural or otherwise? And finally, where do you recommend seeking experience to be more valuable in this upcoming industry? Any resources, names or insight you can offer would be greatly appreciated. I am also attempting to make contact with your long-time pal and fellow AVF board member Henry Gordon-Smith to pick his brain.

Keep up the incredible work, and on behalf of my generation, thank you for being the voice of sustainable progress in agriculture!



FYI – we are now developing a design tool for vertical farmers in Australia, to assist in the decision making of when, where and how to build a VF. This is an attempt to quantify the costs associated with vertical farming in Australia, and the possible economic reward it poses. Here’s to hoping this has an acceptable engineering hook!

Robin writes:

Infrastructure doom: 25 Million Miles Of New Roads In 15 Years Spell Death For Life On Earth : collapse

Tarwin writes:

I can’t remember if you do a pick of the week, but I was impressed by this article in Bloomberg about an urban, actually underground, farm, in an old bomb shelter under London.



Kevin writes:

Dear Dickson,

This might be a shot in the dark but, I figured I had nothing to lose. I am a young college student from Florida. My good friends and I are in the process of writing a business plan for our dream business, a Vertical Farm in Miami. I study sound engineering and my goal is to incorporate an ultrasound system to stimulate the plants. I will be in New York City for work the 26th of September all day and the 27th until 5pm. It would be an honor to meet with you. Please let me know if this is a possibility, any wisdom you have for me can help.


Karney writes:

Great podcast!  My documentary about urban farming around the world is now streaming online – attached is the press release.

I’d love to be a guest and tell you about my travels!