Fertilizing Plants With A Custom 3D-Printed Pump

For all but the most experienced gardeners and botanists, taking care of the soil around one’s plants can seem like an unsolvable mystery. Not only does soil need the correct amount of nutrients for plants to thrive, but it also needs a certain amount of moisture, correct pH, proper temperature, and a whole host of other qualities. And, since you can’t manage what you can’t measure, [Jan] created a unique setup for maintaining his plants, complete with custom nutrient pumps.

While it might seem like standard plant care on the surface, [Jan]’s project uses a peristaltic pump for the nutrient solution that is completely 3D printed with the exception of the rollers and the screws that hold the assembly together. With that out of the way, it was possible to begin adding this nutrient solution to the plants. The entire setup from the pump itself to the monitoring of the plants’ soil through an array of sensors is handled by an ESP32 running with help from ESPHome.

For anyone struggling with growing plants indoors, this project could be a great first step to improving vegetable yields or even just helping along a decorative houseplant. The real gem is the 3D printed pump, though, which may have wider applications for anyone with a 3D printer and who also needs something like an automatic coffee refilling machine.

20 thoughts on “Fertilizing Plants With A Custom 3D-Printed Pump

  1. [T]hat is completely 3D printed with the exception of the rollers and the screws that hold the assembly together and the electronics and the motor and any of the hardware to control the motor and the tubing and the power supply and the PVC coated wires and any of the crimped, metal plated connectors and any of the injection molded plastic housing for the connectors and probably a few other items as well that are not even in the photo.

    Not sure that saying it is almost completely 3D printed is technically even close to being accurate.

      1. Agreed. If it were me I’d spend the less than $10 it costs to buy one of these off ebay. This is cool from the “I did it myself” standpoint, but for something like this I’d rather buy it and spend my time elsewhere.

      2. Indeed. The three bearing pivots look to be a weak point for layer separation at the triangluar armatures, if these were changed to use a steel screw through them it should be somewhat more durable. It’s a nice compact model though, I like it.

    1. Yeah, a more accurate description would be that it consists of 3d printed parts and fairly cheap & generic components, but that doesn’t make a exciting description.

      Biggest hurdle regarding the generic-ness is the stepper motor and bearings, but using steppers with specs common to 3d printers and “skateboard sized” bearings and you’re using the most jellybean equivalent of those.

    1. As usual, it depends in part on timeframe you both wait plus how long you have used the tube (and at what speed rate before stopping it) plus also very much the tubing material used and what you put inside the tubing exactly. A peristaltic pump, by definition, is always going to be closing off at least one area of the tube when idle.

      Some of the tubing materials, such as silicone or a thermoplastic elastometer are likely to almost never bind together enough such that a few PSI (or less) is not going to immediately open it up as soon as you run the peristaltic pump again. On the other hand, not every “hose” (tubing) is going to work at all in most peristaltic pumps but there is at least a fair variety that can be. PVC tends not to be a good peristaltic pump tube as one example but there are several that are commonly and commercially used that work well in that application.

    2. I had a setup where I was pumping nutrient solution constantly and I found that the hoses didn’t last very long. I moved to a non-peristaltic solution pretty quickly.

      I would expect that having the pump stopped in the same position for a long time would also cause problems.

      These hoses are really a disposable item, and the good ones are pretty expensive to have to keep replacing.

  2. Very cool – although I would worry about the hose crushing and creasing over time, maybe even bursting eventually. Maybe a way to disengage the rollers when the pump isn’t running?

    1. I see no reason why the rotor could’t be placed on an off center cam that engages when rotation starts, and disengages when finished pumping. Does that not exist already?

      If not, there’s a patent for someone, you’re welcome.

      I thought of the starwheel setting mechanism on a lever arm used in calender watches to come up with that. On many calendar watches, the thing that actually moves the date disc is a multi tooth gear like sprocket that swings into engagement when the setting mechanism is turned thru a short gear train to the watch crown.

      If you put a gear between the rotor with the three bearings and the motor on a sliding pivot in a Groove and spring loaded it it would disengage when not on but when you turn it on the gear pressure would drive the sliding pivoted gear underneath the three lobes and swing that whole assembly into engagement with the tube, and stay there under rotation until power is taken off the connection where it would disengage under the pressure of the spring pulling back.

      I hope that makes sense.

      1. Clever idea, but unfortunately it’s not likely to be useful for a peristaltic pump. In any application where you are using the pump to transfer a measured amount of liquid, you need the idle pump to seal the hose in order to prevent siphoning. Otherwise an uncontrolled, unmeasured amount of liquid will be transferred after you stop the pump.

    2. As I understand with these sort of pumps, part of their appeal is that you can control relatively precisely how much fluid you are dispensing (in this case getting the right dilution level of your fertiliser). If you were to disengage the roller then you would need another valve in the system so that you don’t have to prime it each time it’s required to dispense, if you didn’t then you’d end up with air in the line ruining any calibration you’d done on your steps/ml. If you’re not bothered with dispensing a measured amount of liquid and don’t mind priming your pump each time then you could certainly do as you say but I’m not sure the advantage would be worth the extra effort.

      1. Yes, no check valves because the hose pinch stops flow at that point.

        If you need a more robust system the metering pumps for cooling towers and commercial swimming pools are about $200. Ptfe pistons and check valves, last a pretty long time before failure, and there is usually a dial to set the dosage rate.

      2. This was my thought as well, it was always my thinking that peristaltic pumps have to stay fully engaged at all times to remain functional without calibration, but the mechanical side of me took over and wanted to just address the question posed by a couple people on how to make disengagement functional.

        I think the correct solution would be to simply buy the correct tube material and perhaps make it a short section that you can join two other types of piping so it can be hot switched out if it does suffer. I’m not too knowledgeable on plastic tubing characteristics for these things and if any ever permanently bind or what lasts the longest but I think of modular section just inside the pump area would work.

        I wonder if they don’t already do this in hospitals.
        Not sure.

        1. In hospital applications where peristaltic pumps are used for infusions, the piece of flexible tubing from the drug supply to the patient is threaded through the pump, kind of like an old VCR tape. All the tubing is single use and disposed of after the supply runs out, or when the patient is off the medication, so there’s no concern for long term durability of the tubing.

          They can’t reuse the peristaltic portion of the tubes because there’s no practical way of safely cleaning them to medical standards.

  3. I never comment on here, yet the negative and a clear lack of understanding for its purpose is evident. This is actually a very good design. Some of the comments here are absurd; initially, I would learn proper grammar and sentence structure before critiquing a DOSING PUMP! In regards to wearing down the components, everything wears down, you are layering weak plastic! Why isn’t everyone machining all their parts on routers???This is not designed to move large amounts of fluid. A well sorted hydroponic system or saltwater reef tank would require many of these.

    1. I agree with you, I’m from argentina and peristaltic pumps are pretty expensive hear, even the chinese ones, and this is an excellent design, at least for testing and for amateur hydroponics purposes. The only razonable argument that I have read is the concern about the layer separation in the bearing axis, but that could be solved for example by using a bearing with a bigger internal diameter, a 687 for example. Sorry for my grammar and sentence structure by the way, I’m working in my english jajajja

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