Aeroponic Greenhouse

Hi everyone,

First off, thanks to everyone on this forum for sharing their projects, knowledge and ideas. I used it extensively when designing my system. I want to share my build process and results with everyone… Constructive feedback is appreciated.

I live in Toronto, Canada so our growing season is limited. We also have a racoon problem in the city so growing any veggies outside means you’re unwillingly making a food donation. So I decided to build a greenhouse to extend the growing season and solve the animal issue.

Here are the specs at a high level.

Overall Design

  • 4’x10’ growing area
  • Double pane insulated glass on two of four walls
  • Insulated roof and insulated non-glass walls
  • 4’ deep pit for roots, 7’ tall growing area
  • Automation through raspberry pi and smart plugs

Root Box

  • Insulated root box sunk 4’ into the earth to temper extreme weather conditions
  • Copper tubing buried under the pit for future use (exact use TBD, briefly used it to cool the nutrient water during summer)
  • Rubber pool liner seals the root box area from (most) insects
  • Six netafim coolnet pro nozzles with check valves mist roots. One diaphragm pump feeds 80 psi nutrient water to nozzles through 1/4” push-lok tubing.
  • Small pump with float switch drains excess water from pit to outside (non-recirculating setup)

Growing Area

  • 22 growing spaces, each spaced about 12” apart
  • 6 growing zones - each zone is made up of white lexan plastic trays and cedar framing. Plants sit in 2” net pots with foam inserts.
  • LED lighting provides additional light on overcast days, and at dusk & dawn, scheduled through a smart plug.

Heating/Cooling

  • Small electric heater keeps the space 10 degC when OAT is -25 degC
  • Small fan to exhaust air on hot days

Nutrient Delivery

  • Nutrient solution stored in 100L bin. I manually add water and nutrients.
  • rpi schedules the pump to run every 2 minutes for 2 seconds during the day, and every 5 minutes for 1 second at night.

Lessons Learned

  • Need to insulate lexan sheets (the ones that make up the tray of each grow zone). Light and heat is transferred through the plastic to the root box. Causes root temps to get above 15 degC. This is a work in progress, I’m gluing 1” thick blue foam sheets to the bottom of each zone.
  • Cheap Aliexpress nozzles clogged and provided inconsistent spray from day 1. They also allowed water to drain through them when pumps were off. I’ve replaced these with the netafim nozzles, they work much better.
  • I initially recirculated runoff water back into my supply. Even with filters I found this led to algae growth. I never had issues with the algae but figured it could lead to issues so I changed to a non-recirculating system.
  • The growing area and root area both get too warm during summer. I’m planning to supplement the exhaust fan with a fresh air fan. I’m also hoping the insulated lexan will help with the root box temp.

Water Use
I initially used about 70 L/day with the cheap AliExpress nozzles. I’m down to 20L/day with Netafim nozzles and hoping to reduce this further. I plan to measure the volume of waste water on a hot day and cool day. This should be a good starting point.

Thanks for reading!
Daniel

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Hi Daniel
I would aim to maintain a rootzone temperature at around 20c, 15c is a little cool imho. When running drain to waste its better to use an accumulator, pressure reducer and solenoids to enhance control over the liquid delivery and minimise potential waste. In an ideal world, every drop of liquid delivered to the rootzone would be in mist form and every droplet would connect with a root :wink:

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Here’s a video of the nozzles. The cycle time was at 2.9 seconds. It’s now down to 1.9 seconds.

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Thanks Atom, much appreciated. I start seeing the down side of no accumulator as my cycle gets down around 1 second, which is where it should probably be. Based on what I’ve seen so far it seems like running a shorter spray interval more frequently is better than an infrequent longer interval. Seems there is less waste water this way. I know I need an accumulator and will implement one at some point but for now I’m going to experiment with what I’ve got. Have you ever tried to measure moisture in the roots? I’m wondering if there’s a way to automate the spray frequency by looking at moisture levels.

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Hi Daniel
With a pump only system increasing the number of cycles will generally increase the amount of waste as most of it is generated at the beginning and end of each misting pulse. From the pics it looks like the adv`s on your netafims have purple or possibly blue pins, i would recommend using the 4 bar type if you can get them which have orange pins.

netafim%20adv
Here are the opening and closing pressures for Netafim ADV`s
Blue Opening Pressure 1.5Bar, Closing Pressure 0.7Bar
Purple Opening Pressure 2.0Bar, Closing Pressure 0.9Bar
Green Opening Pressure 3.0Bar, Closing Pressure 1.5Bar
Orange Opening Pressure 4.0Bar, Closing Pressure 1.8Bar

I dont use any kind of electronic wizardry to control or monitor my setups apart from basic digital thermostats, humidistats and cycle timers. I think the highest tech piece of kit i own is an IR thermometer :wink: I judge root moisture by eye but you will find as you grow different crop types and gain experience youll get to know what they need. I always recommend testing the systems actual flowrate so you can put a accurate figure on what you are putting into the root chamber. I made excel spread sheets for all my systems which make it easy to see what difference any changes (timing, pressure etc) will have on the per pulse, hourly or daily flowrate for that system.
The white top on your chamber is allowing light to get to the roots which isnt good, i`d try to address it asap to prevent algae growth ;),

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Yep, I tried getting the orange pin valves, couldn’t easily find them. I’m in the process of adding blue foam insulation to the lexan panels, this should cut the light and help keep the roots cool. Thanks again!

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Sweet setup! How long did it take you to come up with the concept?

Thanks tman!

I started designing about 18 months ago. This is my first growing season. I went through many design iterations before I started building and even now there are many things I would do differently and am planning to change.

If you’re planning to build, my suggestion would be to start small and focus your energy on the portion of the project that really interests you, whether it’s programming a controller, designing, or the actual build. I took it all on and went large scale, so it took me a long time to get here and making changes to the final product are very expensive. What I’m trying to say is start with a small version of what you’ve got in your head and grow the idea as you learn from each iteration. Good luck!

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Dude that’s awesome! I can see where you get an idea in your mind and you have to plan and plan to get to it. Vs starting out with a 5 gallon bucket build and fling from there. I’m trying to design a setup like art garden but just running a blue barrel. I really like that idea for a tower. I’m running into a problem with selecting a pump and nozzles and how to plumb everything. I know I want to actually run 80-100 psi pump to atomize the water and nutrient but i dont think i understand the math behind nozzle selection. I’ve seen @atom be amazing with those. But I’m taking it slow, found out about aeroponics 2 weeks ago and im bought it, just want to build a system myself since I like to build things and some of the prebuilt systems look like junk.

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If you plan to run one tower with just a pump, id recommend using an aquatec 6800 which will cope with the cycling. Two or three upward firing hypros mounted in the middle will be enough to fill the barrel with mist. With a pump you`ll likely have to recirculate the nutrients, The ideal reservoir is something like a 25-30L coolbox connected via a tube to a central drain fitting (john guest tank connector cut or sanded down to minimise the internal height). Side entry into the coolbox reservoir is best, it will allow you to remove the lid and keeps everything well sealed. Contrary to popular belief you dont need to use an airstone in the res to keep it fresh :wink:
Fit a 1/4" supply line from the coolbox reservoir to a good quality inline filter (250 mesh min) and connect the output of the filter to the inlet side of the pump. I dont recommend fitting the filter after the pump as that will leave it unprotected :wink:

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Wow, 18 months! - that’s a beautiful piece of work! You’ve inspired me to be more focused and change from thinking about my designs to building them. Thanks for sharing and especially for including the photos and video!

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Thank you! I hope you decide to turn your ideas into reality. And if you do please take lots of progress pictures and share :slight_smile:

@atom, you described what I want to do exactly! Can I ask a huge favor, as this is what i’m struggling with for my parts list. I agree with the upward fire hollow cone for fine mist. Can you or somebody on here explain it to me like i’m 5; I can’t figure out exactly what part number nozzle I need. I think I’m following everything that’s been said as far as orifice size, spray pattern, and line pressure to get the atomized mist but when I go to look up nozzles I feel like I’m not looking at the correct ones. Thanks for the help!

I use two Hypro AFD 0.7-80 nozzles in each of my towers. Each nozzle on its own 12v solenoid which is supplied by the accumulator. If you run with just a pump, 2 nozzles will be pretty hard on it due to the large number of cycles it will have to cope with.