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reserve your ad hereHey, greetings greenies! I’m The Rev – and today I wanted to babble a bit about TDS meters, and more broadly get into some info regarding the PPM values of your plant water. I have been growing cannabis for over 50 years now, so I think I know a few things about it, heh heh. Oh, and definitely human writing here, LoL.
I have had inaccurate PPM readings almost ruin a perfectly awesome harvest before, and it’s heartbreaking to say the least. Today I am going to try and help you guys get a grip on avoiding this stuff and how I do it all myself.
I wrote my latest book, (True Living Organics) the Druid’s Edition, about growing in living soil, using a bit of a different approach style. A lot of weight on powerful soil mixes, then it is full of tools. It really teaches you to assess your own environment and use what you have easily available to you. Check it out here – True Living Organics the Druid’s Edition by The Rev. It can literally change your life for the better. Okay, onwards we go…
I Actually Use Two Different TDS Meters and Here’s Why
My most reliable TDS meter is my Apera TDS20 (less than $60.00 on Amazon now). This meter is waterproof—more important than you may think—and takes about 90 seconds to give you a very accurate reading on the PPM of your plant water. It is very simple to calibrate—a huge consideration—and runs on two AAA batteries. I love that whole “normal” type battery thing. At the time of this writing this meter comes with a nice little case. You get calibrating solution and instructions etc. in the case along with the meter. Here is a link: Apera TDS20 Waterproof TDS Meter. I just put a little water in a cup and let this meter sit in it for 90 seconds for a good read.
My other meter is a cheap (under $12.00 at the time of this writing) meter also available on Amazon. It gives an instant (almost) reading. The brand is Craft 911 and I have been using these cheaper meters in tandem with my Apera TDS20 for several years now quite happily. Here is a link to my cheap meter: Craft911 Lower Quality but Still Fine TDS Meter.
I mostly just use my cheap meter because it reads the PPM fast. I usually use the Apera meter to double check my cheaper meter. The cheap meters stay pretty accurate in my experience for about a year. After that point they tend to under-read the true PPM value of your water. So, the meter may say 59 PPM while tour actual PPM is closer to 69—yikes! So, I replace my cheap meters about once a year and I check their accuracy about once every 2 weeks. Boom! If I only had one meter, it would be the Apera TDS20 TDS Meter
Two Formulas to Read the PPM Value are Used
Okay, here’s a “thing” you need to know. Cheaper meters and more quality meters generally read the PPM value using two different methods revolving around EC (electric conductivity) conversion. For brevity we’ll call the cheaper meter conversion method the 500 method, and the more quality meters the 700 method (see illustration below). My higher quality Apera meter uses the 700 method and my cheaper Craft911 meter uses the 500 method. Got it? Gooood 😊
If you’re worried about having to do complicated math or something to figure out the difference, don’t be. It’s super easy. If I read my Apera TDS meter and it says my PPM is 89. How do I find out what it would read on my cheaper TDS meter? Easy… 89 x 0.714 which equals 63.5, boom, easy-peasy man. To go the other way, converting a 63.5 PPM reading on the cheaper meter is easy too. 63.5 x 1.4 = 89. It’s easy, either multiply by 0.714, or by 1.4 depending on which way you want your conversion.
Your Plant Water PPM
In my book I give you my target PPM values for my plant water. I normally run my plant water in the high 50’s to low 60’s regarding PPM—as read on my cheaper TDS meter—and this would be low to mid 80’s PPM on the Apera meter, FYI. Now let me say here that your PPMs could vary a lot depending on your style and environment. For example, if you just use groundwater and use traditional living teas, your groundwater may run 49 PPM and your teas you use once every two weeks or so may be closer to 90 PPM—these PPM values are all in the cheaper meter values, the 500 method.
I like to keep my water slightly amended almost always rather than goosing them once every two weeks. I either use The Churn method from my book, or I amend my plant water before use. As my plants approach harvest time I gradually reduce my PPM values, eventually ending up back at pure groundwater for the last 10 days or so before harvest. My groundwater is around 49 PPM and I run it around 60-ish PPM (500 method) juiced up with aquarium water and worm farm leachate—worm juice!
There are several options when it comes to watering your plants and giving them supplemental food as I outline in my book. The book is meant to help you adapt to whatever your environmental conditions are. Grab yourself a copy from the link at the top of this article and give it a whirl. You’ll love it!
Afterword
Make sure your PPM readings are accurate man; it’s a rude awakening to have a salt toxicity issue as harvest approaches. That’s exactly what can and does happen from going too heavy on your PPM value in container growing.
Well, that’s about it for me today my friends. Want some more Rev writings? Check out this article: MILF Rev’s Rave Blue Rhino 1947 from KOS. Make sure to grab yourself some killer genetics to start off your grow right, here at https://kingdomorganicseeds.com is the place to do it, yessir.
I give all my own PPM values in this article using the 500 method, unless stated otherwise, just for clarity. I’m outty for now, but I’ll be back. Take care and good luck in the world of today. L8r G8rs.
- REv 😊
