Controlling Nutrient and PH


Hello, how does the control of the PH and nutrient level work?
Is there a pump or something that delivers these solutions after monitoring them?
Thank you.


I don’t know how they do it with the food computers, but hydroponic commercial growers use injectors (injection system). The injectors are installed in the water feed lines and inject the right amount of nutrient and/or pH as it’ passes by the injectors. Depending on the type of hydroponic system the injectors can be controlled by simple water flow, or sensors and computer controlled. Most commercial growers use a hydroponic Drip system and control the injectors by water flow.

The injectors are set to the amount they want, and when the water starts flowing through the tubing the injectors are turned on. When the water flow stops so does the injectors. This gives a constant flow of the exact nutrient and/or pH to the plants as needed. And without having to mix large batches or maintaining large reservoirs.

For home hydro growers, simply checking pH with pH drops and fallowing manufactures instructions for mixing nutrients is all that’s needed. Some home growers like using pH and EC/TDS/PPM meters for checking pH and nutrient strength, but their not needed and can give false readings as well. Relying on EC/TDS/PPM meters can even be misleading if you don’t understand how they work and what their limitations are. Fallowing manufactures mixing directions and watching your plants will tell you if your nutrients are unbalanced, to strong or to weak. It doesn’t take long to recognize the signs when you watch your plants grow. .


Thanks for your reply, that was very helpful.
I would like to build my own PH and nutrient control system.
I see Adafruit has a parestolic pump for $25.


There are many nutrient/pH injection systems on the market, though their not exactly cheap. At least not in my book, but I guess “cheap” is a relative term and it all depends on how elaborate you need it to be and how deep your pockets are. I know you said you wanted to build your own system, but I don’t think you mean you want to design the parts on a cad program and have them manufactured. I assume you mean buy the parts and put it together yourself.

I don’t know what your motivation for having an injection system is to automate nutrients and pH, or the type of hydroponic system you want to use it with, or even how many plants you will be feeding with it. So I have no idea whether doing so makes any sense. You can buy the parts separately and custom design it for your needs, but they still cost money.

It can range from a 3 to 4 hundred dollars for one nutrient injector to $5,000 for a multiple nutrient injector system. pH injection increases cost since it needs to be commuter controlled and requires both pH up and down injectors. If the hydro system recirculates the water, you need to add sensors and computer controls to the nutrient injection system as well. The point is unless you just have fun spending money and find it challenging and rewarding, there should be a economical reason to go to the trouble and expense, otherwise your just wasting money.

For some designing things and the challenge of figuring out puzzles and overcoming obstetrical s where all the fun is. That’s what the food computers are all about, But just because you can make something more complicated and expensive, doesn’t mean it’s better. However if your growing a large number of plants for profit, then it makes economical sense.


Thanks for your reply and the info.
It’s like you said,“designing things and the challenge of figuring out puzzles and overcoming obstacles where all the fun is”.
If I could, I would build a control system to control everything.


Good enough,

Here are a few links explaining injection systems
Fertilizer Injectors
Greenhouse Fertilizer Injectors
How to Mix a Stock Fertilizer Solution for Injectors

Here are a few videos explaining injection systems
Arizona Fertilizer Injector Board
GrowBot with Easy Feed Nutrient Delivery System
Using the dosatron
Dosatron Fertilizer Kit
Dosatron Water Powered Doser offered by Sunlight Supply, Inc

Here’s a system for smaller setups.
iFarm controller at Steve’s Hydroponics

Here are a few links to manufactures and retailers selling injector systems
iFarm Farming Process Controller
Nutrient Control
Fertilizer Injectors
Easy feed systems
Hydroponics Injection Systems
Crop King Nutrient Injection Systems
Greenhouse megastore Fertilizer Injectors
Automation Systems for Engineered Environments

I have seen a lot of people design their own environmental control systems, but they always seem to loose interest because they forgot the whole point is growing the plants in the first place. I always recommend growing the plants first,to get some experience growing them. Not only for the experience of growing them, but to learn what needs automation and how best to implement it. But they always want to skip the part about growing plants first, and so they spend all their money building something only to find they spent all their money for nothing, and/or just have to redesign it later because there was so much they didn’t understand about growing plants hydroponically in the first place, or just didn’t care about growing plants in the first place. That’s why I recommend getting the experience first, then design and automate as you go. That’s the best way to be successful.


Thanks for all the great links and the advice.


Growing plants first was the best advise i have come across in this site… I understand and totally agree with your comment Home Hydro. I was on the COB led light post and i feel they were missing the point as well. Yet I admire their ingenuity and dedication and comprehension of electronics. Just to add one more point aimed at this post… for gods and human’s sake, think ORGANIIC.


It could very well be that our genus/species will end up roaming the galaxy but i would feel better if we first focused on healing ourselves and mother earth first. The whole idea of machines producing our food is abrasive. Kitchen scraps worked over by microbes i feel is a good arrow to follow. But maybe that feeling is of the past???

This is where i have placed my notes when i was younger than i am now. But like i said… maybe i am just a romantic.