Fogponics: The collected works


#1

So let me start by saying I only wish I had found these to threads before my first version instead of during my forth build…

Experimenting with fogponics, could you help?
External Fogponic system design

But I did find them and they managed to answer a lot of questions but several new ones have come up that made me think it was time to reach out to people that may know the answers. But first a bit about some of my previous designs.

I skipped right over the traditional mister in the bottom of a tote under the plant design. I had misgivings about the mister heating up the roots or worse yet the root growing down into the mister. So I started with an external fog tank design.

Well the v0.1.0…it was bad…really bad and totally didn’t work…at all. (I would post a pic but I want you guy to take this seriously and it was really that bad.)
But some googling and a few chats with a pond guy and we get v0.2.0.

This wasn’t bad for a first(sort of) attempt.

THE GOOD:

  • Small
  • Cheap…$45! Only had to buy the 2 x ultrasonic misters ($15 or so on amazon) and that way over priced 1/4 brass nipple ($9 freaking dollars! Never again lowes…) and a bunch of hot glue sticks

THE BAD:

  • The fog was weak but adequate for seed starting or one or 2 plants full time
  • Small 1qt tank + misters = about 1.5 hours of of mist before you need to refill it.
  • No floats for the misters! (literally the worst part of the design) because it made keeping the water at the right level an issue to say the least.
  • Had to try using an on/off timer, USB submersible pump, and a larger plastic tote (about 10 gallons) to try to keep the water level right. It sucked I don’t recommend it at all.
  • That 1/2 inch clear tube was the devil I swear…bubbles keep forming inside it and the tube and it was squished from being in the junk bin forever. Kept having to go check the line and pop the bubbles to keep the mist flowing.
  • Tank leaked mist ALOT! unless you can find an air tight tank to use for this you will have leaks. But I did learn PRO TIP 1: Some self-stick window weather stripping and/or an old bicycle inner tube can make all tank mist leaks negligible with a little patience. You can also use this stuff to make grommets around your net pots.

Which brings me to v0.3.x. The X is because there were like six or seven revisions based around this design.

THE GOOD:

  • Floats for the misters! This is a mandatory part of an design going forward. Just fill and forget!
  • 3 x misters = thick fog! As you can see in the image the 2 5 gallon root tanks in the back where constantly full of fog.
  • Big 10 gallon tank (about 7 gallons of water/nutrient) lasts about 5.5 days with the misters running 24/7 before you need to refill.
  • Larger 6 inch USB fan = way better fog movement. Plus that PC fan I originally had crapped out and it made me realize PRO TIP 2: The best fan for the job is one that is low speed but has big blades. A higher speed fan will dissipate the fog before it can get spread out inside your system. A low speed fan with big blades forces more air into the tank, creates a low pressure that evenly distributes the fog in the system.
  • Replaced the clear 1/2 tube with 1/2 irrigation line. Made line bubbles few and far between BUT they did still happen.

THE BAD:

  • FORKING LINE BUBBLES! Had one go unnoticed for like 2 days and totally killed one of my test plants. The culprit was the 1/2 inch barb adapter I used to connect the irrigation line to the tank. Which taught me PRO TIP 3: Fog must be moved in 1 inch or better tubes to avoid line bubbles.
  • The larger tank requires an air stone to keep nutrients from settling to the bottom and separating.
  • Cheap Amazon misters are not, I repeat not, meant for anything more than straight up water. Hear me about before you tell me I’m wrong. Of course they can atomize nutrients in to mist like a boss, but they will become clogged up and caked with nutrient residue. Not that this doesn’t happen with larger more expensive misters, but it can be fatal to cheap ones. You must clean the misters at least once a week (just take them out and spray them in the sink) while running nutrients. If you let them get clogged they shut off and may not come back to life after cleaning.
  • No condensation returns from the root tanks to the main fog tank. This was kind of a deal beaker and I totally should have thought about it. After a few day i bumped into the system and one of the root tanks fell over and spilled about a gallon of fluid…on to an unsuspecting power strip. Condensation must be managed and routed back to the tank. Doing this expanded extends the run time by about 1/2 even more if you can keep fog leaks to a minimum.

Which brings me to v.0.4.2

Hands downs this system is way more advanced then any of it’s predecessors.

KEY FEATURES:

  • 10 head industrial mister - Several orders of magnitude thicker fog. The cheap ones have like 10-16 mm heads on them, but these bad boys are 20 mm! Actually way more than I need for the root tank space I have setup right now.
  • Adjustable voltage power supply - Makes it so you can dial in the fog thickness
  • 55 Gallon fog tank - With at least 40/45 gallons of nutrients/water in the tank this system can run for 2 weeks or more.
  • Unified Condensation Return Both the flat grow bed and vertical tubes use the same 2 inch fog pipe to route the condensation inside the system back to the tank.
  • Mister Cleaning/Fluid Circulation System Using a few submersible USB pumps the fluids in the tank keep circulating and the output of one them is directed to spay over the mister heads thus keeping it clean as a whistle.
  • Adjustable/Expandable Design The the flat grey box allows a space for germination and cloning. While the 2 foot long 4 inch vertical tubes can twisted horizontally.They can replaced with longer ones on tubes with different hole configurations.

Now before I fire this system up and fill it up with test veggies. I have questions.

  1. ON/OFF Cycling Misters I’ve read a lot of back and forth on this, but for the most part the reasoning behind it seems to be to prevent the mister heat from affecting the roots. With an external fog tank system that that shouldn’t be a problem. I’ve been running some of my systems 24/7 and I haven’t seen any significant heat in the root tanks.In fact I’ve been suspicious of exactly the opposite because the fog seems to keep the inside of the root tanks pretty cool compared to the outside (greenhouse/garage). I keep the root tanks at humidity around 85-90% ad the temps have been around 63.
  • Do I really need to On/Off cycle the misters?
  • Are there any other benefits to doing this?
  • How long should the on/off cycles be?
  • Is there a target humidity level to shot for in the root tanks?
  • How cold is too cold for the root tanks?
  1. Nutrient Fog In my v0.3.x system when I switched from water to nutrient mix the first time I wasn’t sure what to do the first time i needed to refill the tank?
  • How much nutrient is too much/not enough?
  • Do I always refill with a full strength mix?
  • What happens if do a cycle? (i.e.- full strength, then top off with water, then full strength)
  • Should I empty and refill the tank so that the left over mix doesn’t mess with levels in the fresh new mix?
  1. Brains & Sensors As you can see from my designs I haven’t deployed nearly the amount of tech I could. Sensors, relay controllers, raspberry pi’s yeah I got all that waiting in the lab to be deployed on this.
  • What all should I want to track?
    NOTE: I’m already planning:
    - Cameras with computer vision to watch the leaves for problems
    - An Ultrasonic distance module monitor to tank levels
    - Relay Controllers to automate lighting
    - Light sensors to measure light saturation and canopy penetration
    - Temp/Humidity sensors for the tank, root areas, and near by ambient
    area
    - Backup battery with 48 hours of run time
  • Anyone know a good fog density sensor?