Need Guide for this PPM runoff in Coco

Doug Dawson

Well-Known Member
Okay so just use half the strength in my 10L than I have been doing, even though my plant is in full bloom ? I was thinking just to feed plain water for my last 10 days
You never give plain water in coco, it's just bad for your plants. If you feed too much or are getting nute lockout you can flush your coco with 25% nute solution to break down salt buildups and such but never just plain water. Because coco has nothing in it by default you don't want to wash all your nutes out and leave the plant to starve until your next feeding which is why if you have to flush your medium you use 1/4 to 1/2 strength nutes.
 

myke

Well-Known Member
I’m at 3 weeks flower my girls get about 500 ppm food calmag tap total. Tap is 150. My runoff yesterday was 1300. So today I’ll run about 350-400 and feed twice to runoff. This is normal. Once a week i have to correct it so it doesn’t build up.
 

Doug Dawson

Well-Known Member
I’m at 3 weeks flower my girls get about 500 ppm food calmag tap total. Tap is 150. My runoff yesterday was 1300. So today I’ll run about 350-400 and feed twice to runoff. This is normal. Once a week i have to correct it so it doesn’t build up.
HMM. I am in my 5th week of flower and have been feeding them around 1100 ppm since 3 weeks before flip, I never have to correct for buildup. I would think if your medium is retaining so much that you are not getting enough runoff every day or you are letting your coco dry out which will cause the salts to dry out and build up. That is why coco users are to do sufficient runoff every day, to push the salts and such out while replacing them with new food. You could lower your feed to say 200 PPM, flush out your coco until you get around 200 PPM coming out and than just give them a normal dose of nutes. Carry on from there but if you are getting that kind of buildup in your coco you need to get more runoff every day so you don't get the buildups you are getting IMO.
 

bananahaze64

Active Member
Okay so to summarise when I am nearing harvest the aim is to keep the ppm of the run off as close to that of the tap water (230) is it not a good thing If water with a solution 780 and then the run off is lower, eg 360 , ad this means the plants have uptaken what they want
 

myke

Well-Known Member
Okay so to summarise when I am nearing harvest the aim is to keep the ppm of the run off as close to that of the tap water (230) is it not a good thing If water with a solution 780 and then the run off is lower, eg 360 , ad this means the plants have uptaken what they want
Your meter is not working correctly.Most dont check runoff but sometime around week 6 or 7 leaves start showing signs of build up.Small corrections weekly will avoid this especially if your strain like mine is a 10 week.
 

myke

Well-Known Member
HMM. I am in my 5th week of flower and have been feeding them around 1100 ppm since 3 weeks before flip, I never have to correct for buildup. I would think if your medium is retaining so much that you are not getting enough runoff every day or you are letting your coco dry out which will cause the salts to dry out and build up. That is why coco users are to do sufficient runoff every day, to push the salts and such out while replacing them with new food. You could lower your feed to say 200 PPM, flush out your coco until you get around 200 PPM coming out and than just give them a normal dose of nutes. Carry on from there but if you are getting that kind of buildup in your coco you need to get more runoff every day so you don't get the buildups you are getting IMO.
Not sure if its diff coco brands or the fertilizer but Ive always had more ppm going out then in.I shoot for 3-400 ppm more then that its time for less.I run off every day but i use less nutes if i once a week to a heavy runoff with less ppm.I think it stays more balanced then.Ive had many coco grows and used diff nutes ,always have more ppm in runoff even if i feed 2-3 times a day to runoff.
 

twentyeight.threefive

Well-Known Member
Thanks for the replies guys was really good, i tried again today and it was 230 from the tap 790 with the nutrients mixed in then 380 in the run off this time so im guessing thats good, the only thing I can see is my leaves going slightly yellow/lighter from the stripes of the leaves what do you think
That makes no sense. If you are feeding 790 ppm nutrient solution and only 380 ppm runoff is coming out then your plants would have to be pulling 410 ppm of nutrients out of your feed. That's not happening. You started the post off with asking "how this whole ppm malarkey works", I think something must be off with your whole process of checking it.
 

bananahaze64

Active Member
That makes no sense. If you are feeding 790 ppm nutrient solution and only 380 ppm runoff is coming out then your plants would have to be pulling 410 ppm of nutrients out of your feed. That's not happening. You started the post off with asking "how this whole ppm malarkey works", I think something must be off with your whole process of checking it.
Why cant they take 410 of the nutrients is this to high amount or too low, aside from my meter being off I just submerge it in the water and wait for the number
 

bananahaze64

Active Member
If i water every day it would make sense the ppm of the run off is 380, surely because i water each day to run off so it shouldnt really exede 780 (as this is the max amount going in) im not watering a little every day to build it up in the coco to 1000+ The tap is 230 the nutrients is 780 so the plant takes the rest what it needs esch day and then i mix up a fresh batch the next day. Or am i way off
 

BBQtoast

Well-Known Member
The Coco acts as a filter, it has charge and ions will not pass through unaffected.

You need to ignore runoff, what it's telling you is to stop trying to find meaning in it.
 

twentyeight.threefive

Well-Known Member
Why cant they take 410 of the nutrients is this to high amount or too low, aside from my meter being off I just submerge it in the water and wait for the number
Yes. If you are thoroughly soaking the coco it would be impossible for runoff not to be close to the input EC/ppm.

Are you having an issue with the plant? What's the need to check the run off? Proper feeding amount and frequency should eliminate any reason to check runoff.
 

bananahaze64

Active Member
Yes. If you are thoroughly soaking the coco it would be impossible for runoff not to be close to the input EC/ppm.

Are you having an issue with the plant? What's the need to check the run off? Proper feeding amount and frequency should eliminate any reason to check runoff.
I was just interested as my pen came in the post the other day, I would say the plant is good a little dark leaves with light patches begining in the veins but the flower is going quick better everyday I will take a picture later :)
 

PJ Diaz

Well-Known Member
You need to ignore runoff, what it's telling you is to stop trying to find meaning in it.
I totally disagree. When I'm growing new strains, measuring runoff ppm is a wonderful tool to help determine how much a certain strain likes to feed. As an example, when I grew Slurricane and Wedding Cake side by side given identical feeds, the runoff from the Wedding Cake plants was substantially higher ppms compared to the Slurricane. This helps to guide me towards correct strain specific nutrition in future monocrop crows with those tested strains.
 

calvin.m16

Well-Known Member
You never give plain water in coco, it's just bad for your plants. If you feed too much or are getting nute lockout you can flush your coco with 25% nute solution to break down salt buildups and such but never just plain water. Because coco has nothing in it by default you don't want to wash all your nutes out and leave the plant to starve until your next feeding which is why if you have to flush your medium you use 1/4 to 1/2 strength nutes.
This is true, I did this for a minute and it was no good I track my grows very meticulously and take pictures daily, the crops that I gave feed/water/feed/water definitely suffered vs plants that were fed a milder food solution daily. A good alternative if you want to still feed that full strength (feed chart) mode would be getting into compost teas and doing feed>tea>feed>tea. This is what I do now in coco and it works wonders.

Roots Organics Terp Tea Grow & Bloom alongside Real Growers Recharge are bomb diggity dog just gotta make sure your not adding any shit like hydrogen peroxide or Hypochlorous acid (UC Roots *For some reason this became very popular in the last few years*).
 

calvin.m16

Well-Known Member
If your feeding to run off you want your run off to be slightly higher than what your input feed is. So if you're feeding in 1200 PPM for example you are going to want your run off to be around 1600-1800 PPM (+400-600 PPM output).

You do'nt want to under feed the plants but you also don't want to over feed. It's good to have a run off slightly higher than your input just if you notice its really high like above 1800 PPM you should cut your nutrients back a bit until you get it back where you want it.

You're using a great method of knowing how much to actually feed your plants and I'm legit proud of you for that. Most people are too damned lazy.

Most sources will state that max PPM for nutrient solution when it omes to cannabis plants shouldn't be higher than 2000 PPM, who knows which actual PPM scale they're referencing as there are a few but most commonly there's the 700 and 500 scales. Your meter likely is using the 700 scale.
 

BBQtoast

Well-Known Member
I totally disagree. When I'm growing new strains, measuring runoff ppm is a wonderful tool to help determine how much a certain strain likes to feed. As an example, when I grew Slurricane and Wedding Cake side by side given identical feeds, the runoff from the Wedding Cake plants was substantially higher ppms compared to the Slurricane. This helps to guide me towards correct strain specific nutrition in future monocrop crows with those tested strains.
Runoff doesn't work like that, a Res does.

And that's why years of running Coco we have no runoff charts we can follow.

You can disagree, it's still easier to learn to grow and not use runoff.

You make things harder than they are why?
 

calvin.m16

Well-Known Member
Runoff doesn't work like that, a Res does.

And that's why years of running Coco we have no runoff charts we can follow.

You can disagree, it's still easier to learn to grow and not use runoff.

You make things harder than they are why?
I disagree. You can most certainly know how much to feed your plants potted in coco based on runoff readings. It does not only apply to systems with a reservoir.
 

PJ Diaz

Well-Known Member
Runoff doesn't work like that, a Res does.

And that's why years of running Coco we have no runoff charts we can follow.

You can disagree, it's still easier to learn to grow and not use runoff.

You make things harder than they are why?
So if I observe some strains eating more than others based on consistent differences in runoff ppm, that means nothing to you? My plants are all happy, but I'm trying to dial in specific strains that I run over and over.
 
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