Where's the cooling aspect of the food computer


Hi all
new to this BUT watched video and didn’t see the cooling aspect of the approach??? I am in Pilsen in Chicago and experimenting with the kratky method of growing lettuce. All is well in a temperature range of 55-65 f but above that all turns to crap. SO am I missing something here and the existing system can compensate for exterior temps OR is there something else that needs to be addressed in crops that have lower growth temps like Romaine lettuce.

ALSO if anyone is interested in popping down to Pilsen to chat about this I would be happy to set up a room in La Catrina cafe and we can get Sal and Diana to cater it.


AFAIK V1 design of PFC does not have any cooling possibilities.

V2 suppose to have (at least on render there is dedicated place for that) but so far no details on this.

There are few guys on this forum experimenting in this direction. Here and here


If it were me, I would build a small “reverse” swamp cooler to cool the nutrient solution. It would be the most cost effective way I know of to cool the nutrient solution electronically. Especially if you use temperature sensors to only turn on on and off when needed. I would probably just use a light timer. But I know you guys love to use sensors, gadgets and computers to automate everything. It can also be used to cool the air temps and circulate fresh air to the plants as well.


thanks for the suggestion and I certainly will look into it BUT it’s the internal atmosphere of the computer that needs cooling not the nutrient. In short romaine lettuce seem to want to grow in a low temperature range.


hi there It’s not the temp of the nutrient per se, it’s the environment it grows in. At least I think so. Thanks for the links will certainly look at them


wow what a moron I am, I NOW realize what you were tying to tell me. Sorry about that. I was hooked on my nutrient solution for the kratky and missed the whole idea of using a fluid to cool the computer. WOW what a great start on this forum. It won’t get any better I assure you all :slight_smile
thanks for the excellent help


Hello comicpilsen,
No I was talking about cooling the nutrient solution, and or the air temperature of the growing chamber. That’s what I thought you were trying to keep under control and cool down. The temperature of the root zone as well as the foliage are both important.


thanks again for helping me out. I am trying to cool the air temp in the growing chamber first and foremost. In chicago it gets pretty warm and I refuse to air condition the room where I grow the lettuce, for me it would defeat the whole object of this exercise. I’m still looking at the links you sent me which are REALLY useful, thanks so much


Did you e-mail me? I don’t remember sending you any links. Though that’s not abnormal, I reply to so many e-mail questions by different people and questions I just cant remember them all.


sorry wrong person but thanks for taking the time to help


I wonder if it is possible to use PCM ( phase chamge materials) in order to keep the temperature more stable due that the food computer does not have much of a thermal mass


Hmm certainly worth looking into. My goal is to cool the growing area only. In Chicago we have high humidity and high temps. This pretty much wrecked my kratky approach as Romaine lettuce ( my fav) seems to be VERY picky about it’s range. See below for official version. Will certainly look into PCM ( great idea). Also looking into cooling using our basement though it’s a long shot. thanks again for the idea.


Lettuce does best in air temperatures of 60° to 65° F (16° to 18°C) with
soil temperatures a minimum of 35° F (1.7° C); soil any cooler will
see slow to no germination. Lettuce seeds germinate best at soil
temperatures of 40° to 80° F (4.4° to 27° C), and they won’t germinate
at all if the soil temperature is over 85° F (29° C). If the weather
gets hot, 80° F (27° C) or warmer, lettuce will bolt (go to seed) and
turn bitter.

$300 Food Computer

There are 1,000 varieties of lettuce, have you considered growing a more heat tolerant variety? I know you like Romaine, but you can probably find a more heat tolerant variety of it. Those temperatures you gave are very low even for lettuce. Root zone temps below 35 will freeze the roots. 32F is freezing. Temps below 60 will slow plant growth, and temps below 50 will significantly stunt a plants growth.

Most varieties of lettuce do fine between 65 and 80F as well. I even grew butter crunch lettuce fine until the temps were in the high 80’s The water temps were in the high 70’s as well.

How big is the space your growing in? How much air do you need to cool down?


yep gotcha on the 1000’s of varieties and yep we do grow other varieties but Romaine Paris is the one I am looking at. They weren’t my numbers I got them straight from a site, but impiracal evidence in my office proves the high number is surprisingly accurate. The moment the general temp hit 68 - 70 all the problems went away and the crop is excellent.

Right now the space is

16" wide
36" long
48" high
basically it’s a machine shop shelf with 8 gallon milk cartons on each, all containing one romaine lettuce plant.We use t5 lights to control the growth cycle.
As I said we are using a variant of the kratky method and it’s a blast to run. The MIT computer is interesting to us as we are considering funding a small startup maker group for it in Chicago. Hence my interest in solving the cooling problem. Thanks for taking an interest, I think the ability to maintain a defined temperature range within the computer’s growing area is a must have if this will be deployed in less developed nations.


Is the 16" wide, 36" long, 48" high space enclosed? What is the air temps with the lights on and off (day and night)/? Also do you have a back yard?


no it isn’t we were running a simple test for the first go round, hence my interest in the MIT enclosure. I want to springboard off their research to get our great community working towards apartment growing. Air temps this year ( I refused to put the ac on) were in the 92 - 95 range constantly. The lights have little or no heat output. Yes we have a back yard BUT this initiative is for simple apartment growing only. It would be SO easy to grow outdoors but the issue here is what needs to be done for the average teenager to get going on this given their attention span ( 1 minute). I’ve convinced a few of the local handymen to club together to work with me on this. If we can get this cooling thing under control we will put together a test unit and deploy it in a local coffee shop as a demo to create interest.


The food computers are about collecting data,points not growing plants, much less growing them economically. In fact the food computers are the exact opposite of economical. They also don’t have any cooling or heating systems other than a small fan for cooling and heat from the lights. Like I said the food computers are about collecting data, not growing plants.

I don’t use the so called food computers to grow plants, I grow plants economically. In my world indoor growers use grow rooms to control the environment. The grow room can be any size and there are ways to control all the variables (heating, cooling, CO2, lighting, etc.). But again in my world I have to take into consideration if it’s going to be cost effective, and/or how to make it more cost effective.

Considering the size of the space your growing in which is very small, and the high humidity in your location, I doubt it’s going to be cost effective to grow that little. You can try building a small swamp cooler, but I don’t think it will do much good considering your high humidity. You can run the input air of the swamp cooler through a dehumidifier first. but a dehumidifier uses a lot of electricity. A small window AC unit will probably use about the same amount of electricity as the dehumidifier. If you were growing in a much larger space, using a window AC unit would be much more cost effective because you could get more produce out of the space.

The reason I asked if you have a back yard is because there is a way to use geothermal energy to cool the air. In other words, to use the cool earth/soil as an air conditioner, and while only using the electricity of one small 3-4 inch fan.

As far as I know of the food computers don’t have any heating or cooling systems other than a small fan for cooling, and lights for heating. They essentially rely on ambient room temperatures. The designers of the food computers never considered the reality of heating and cooling. That’s an aspect they are trying to work on, but yet don’t have any answers for. Not in real world applications anyway. I don’t deal in 2 cubic foot grow boxes which purpose is to collect data. I deal deal in growing plants for consumption as economically as I can. In fact I joined this forum to see if I can learn some more things on how I can be even more economical. However not only are the food computers not economical, the main issues facing indoor growers (the electrical costs), they don’t even consider or work on.

That’s why I jumped in on this thread, I wanted to help you. Considering the food computers don’t have any cost effective real world cooling systems, I thought i would try and help you with my experiences, If I knew more about how you have things set up, and the space your growing in, I might be able to offer some more advice. But I guess in the end I don’t really know what your trying to do or accomplish since you referred to some growing program targeting teenagers.

I guess if your trying to design a small self contained, fully automated grow box to fit every situation, all I can say is it’s not going to be cost effective or economical. But it might be a good conversation piece. .


nope got to disagree on some of these points.

the MIT food computers are built to scale up to production levels, our goal is to do just that. Starting with determining what works and how. I agree that the food computer gathers data BUT it also uses that data to maintain the environment. I understand the cost effective goal and we are striving towards understanding that, in Chicago we have many working examples of this in operation and we are tapping into their experiences. Remember this is an apartment installation and so value has to be apportioned to the experience of growing your own produce and the knowledge you know what went into it. It is just a hands on start.

We understand about the swamp cooler and are looking into both geothermal and evaporation approaches, we are trying to get the graphene people onboard but right now they have production issues. The small ac issue can be addressed by, surprisingly, the trucking industry who have harnessed nasa research to develop a functional solar powered ac unit that seems promising.

as to our goals, we intend to investigate scaling this up from the apartment , restaurant , hotel and up. One of the great things about Chicago is that we have access to venture capital which is based in the hotel business, we also have excellent examples of working hydroponic systems that are cost effective. I think we will be successful given the support systems from Northwestern, Uni of Chicago and IIT to help us wring out the kinks. Thank you for all your guidance it really helps to have experienced people point out the drawbacks in the existing approaches.


I know the MIT goal is to be able to scale up, but if you have been around hydroponics for any length of time you would know that there are people all over that have already done just that. Like I said they call them “Grow Rooms” not food computers, Trying to reinvent something that already exists just because you can throw money at something doesn’t make it better, it just makes it more expensive for no reason. That’s fine if you have money to waste, but nobody who actually grows food to eat or sell wants to spend $40 to grow each tomato. That’s simply a waste of time and money when you can buy them at the store for $3 a pound or less. To be cost effective you have to be able to grow them for the same or less than you can currently get them. No mater how you scale up the food computer, it will either wind up costing a fortune, or you will wind up growing in a “grow room” or greenhouse just like everybody is already doing.

Also if you have been around hydroponics for any length of time you would already know that all these data points the food computers are designed to collect, and as you say to use to grow better crops is information that’s already available. Hydroponic researchers have been studying them for decades. Not necessarily for every single type of plant, but for most every common crop grown commercially, Even if the specific variable hasn’t been studied in a particular crop, it has been studied in other crops, and you can apply that information to the crop your growing.

There are only three aspects to growing hydroponically that need vast improvements to make it more viable for indoor growers. 1, Cost effective lighting. 2. Cost efficient heating and cooling (both air and water) while it’s fairly cheap and easy to heat the water, cooling it is another story. 3. Hand held cost effective EC/TDS/PPM meters that can actually tell you not only what specific elements are in the water, but the values of each individual element. I have already had that conversation about these three aspects, and was basically told that the people at MIT weren’t working on any improvements in those areas.When I say improvements, I mean compared to what’s currently in use and available.

While air conditioning that runs on solar energy doesn’t cost anything to run, that doesn’t necessarily mean it’s a improvement or cost effective. Using solar energy doesn’t mean the air conditioner uses less energy, or makes the air conditioner any more efficient. It just means that your using free energy from the sun to run it. Efficient solar cells have been around for decades, and you can get them at many hardware stores or online. When I talk about more energy efficient. I mean actually uses less energy to run regardless of the energy source (solar cell or wall outlet).

That’s why I like the geothermal air conditioner design (subterranean heating and cooling system). The only moving part and energy draw is a simple fan. That uses very little energy, and works best in high humidity like in grow rooms and greenhouses. The major drawback is it takes digging to be able to construct, and you need somewhere you can dig a trench to place it. It also means that the greenhouse or grow room needs to be close to where it was placed in the ground. If sized properly it can cool everything from small rooms to large commercial greenhouses. But it’s obviously not a violable option for growers in apartments or buildings. .

The issues facing indoor growers aren’t in growing healthy plants, it’s in doing so cost efficiently. Millions of people are growing healthy plants indoors hydroponically already, But trillions would be doing it if they could do it cost effectively. None of the data points you collect, nor all the computers you dedicate to collecting them and controlling those data inputs aren’t making it more cost effective. Again that’s just throwing money at it for the sake of throwing money at it because you can.

If I had to bet I would probably say that nobody at MIT working on the food computers really has any practical experience growing plants hydroponically. I say that because of the lack of understanding basic things about growing them I read in the few posts about actual growing plants there are. That doesn’t mean they aren’t smart, just inexperienced. The people at MIT have lots of knowledge about things I don’t. That doesn’t make me dumb, just inexperienced about those things.

I bring that up because in order to really be able to grow plants, you have to really want to grow plants in the first place. As far as I can tell, the food computers are a result of some people who love computers and gadgets trying to find something to apply their knowledge and skills to. But the problem is their passion is in computers, not plants. Instead of trying to invent grow rooms and climate controlled greenhouses that already exist, it would be a far better use of funds and resources to improve the energy efficiency like I mentioned, as well as develop better/more useful testing equipment,


Interesting point of view for a forum on food computers :slight_smile:
here’s my view being very new to indoor plant growing and been of the ilk all I want is fresh lettuce at minimum effort. All of the research you allude to is ongoing and effective, all related to COMPUTER farms otherwise called data centers. So from that we get more efficient cooling systems, Quantum computing research leads us to better lighting and clearly better handheld testing systems drop out of the nano research being done into medical diagnostic systems. This is all ongoing and effective so that’s really not the goal of the food computer as I see it and I really don’t see why this effort should be stopped. As to geothermal it is attractive but how would it be effective in less developed nations where the villages can’t expend the energy to dig the trenches but CAN expend the energy to open the container farm and get it operational. Same question would apply to any area in a city where it is complex to start digging trenches or holes of any size.
as to the experience issue, we wear our ignorance with pride, our desire to grow crops comes of a need to reduce the dependency on others by the consideration of what it would take to place a farm ,such as yours, in each apartment building and available space so that it can be run efficiently and with the minimum of manual intervention. Great strides have already been made in the containerization of farms and this will continue, not in the field but in the lab. The implementation will be in the areas where it is hard not easy, cities…less developed nations, and from the work done by Kratky, MIT and others. I understand all your points and agree with them, it’s just that I see the work BEING done and this initiative is part of that effort. Thanks for all your excellent points and I think we have thrashed this point to death.