General PPM questions.

Hey guys and gals hope everyone is doing well. I have a few questions regarding ppm. I feel like I’m lacking the general concept of it.

When you add all your nutrients into your system you get a your ppm. This number can fluctuate based on temperature and maybe a few other variables. Now you leave your grow and come back the next day take your reading and you get another number.

If that number you take is greater than the first number does that mean the ppm value is too high?


Let me use an example. My PPM the first day was 900 but when I come back the next day it’s 1000. Does that mean that the plants couldn’t take up as much nutrients in the water? In a perfect situation wouldn’t you want the ppm to stay the same just have the water level change?

Any help is appreciated.

It means the plants drank more water than food, skewing the ratio of what is left in the reservoir.

ANC said:

It means the plants drank more water than food, skewing the ratio of what is left in the reservoir.

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So does that mean that there is too many nutrients in the water? Are you better off trying to obtain a point where the ppm stays the same?

Ideally, I'd say that's what you're shooting for. When the eC of the solution stays constant, the ratio of nutrients and water stays the same.

The larger the res the slower the change...
But there should be a change or the plants are dead.
How you deal with it varies from person to person.
Some top up with just water, some people would use 1/2 or 1/3rd strength nutes. Some say fuckit and run drain to waste.

I think you've got it.

I’m just confused when people recommend x for ppm at certain growth periods. I’m a huge cheap ass and I hate waste. Wouldn’t it be better to add enough nutrients so there is a minimum change to ppm over a 24 hour period? My plants seem to hit that at around 850. I’ve seen huge jumps when I go past 950 though. It went to 1100 after 24 hours. The uptake off water also seems to slow down at an unpropertiant rate when I’m ppms are too high as well.

I’ll note too though that even at this magic ppm level there still is slight tip burning. Maybe this signals the indication that I’m still feeding too much. Kind of like stuffing yourself to finish a good meal. I ate it all but now I have to unbutton my pants and go lay in a food coma for a couple hours.

and when helping new people should we not ask for the change in ppm over a certain period instead of their actual ppm value? Genetics must play a huge role in an ideal range to keep it in. With so many strains available today; I have found it hard to even find a solid strain review for my strain.

Sorry if im rambeling I’ve been hitting this dab pen and drinking my cup of joe. Seriously considering finding a way to make these.

i've found that it's much better if you keep PPM constant during the entire grow (that includes seedling stage)

@TIMtoKILL you seem to understand it fine. Anyone who recommends a ppm for you should also be acknowledging that any recommendations should be taken with a huge grain of salt as mileage *will* most definitely vary. Also, you didn’t mention pH - pH swings can cause the plants to consume more or less nutrients but as you mentioned, if your ppm’s are going up and your pH is in check, you are giving too many nutrients. Side note, I’d never recommended an EC or PPM to anyone ever. Instead I’d say read the label, start with half or 1/4 the manufacturer’s recommendation, monitor your solution, and fine tune based on your own analysis and data

In the perfect system ph should rise, ppm's should be constant and water should drop. If this is not happening you need to figure put why.

Ph shouldn't rise to fast but it should drift from 5.5 to 6.2 and then reset. If ppms are dropping you raise your ec level but if ppms are rising then you need to drop your ec level.

TIMtoKILL said:

I’m a huge cheap ass and I hate waste. Wouldn’t it be better to add enough nutrients so there is a minimum change to ppm over a 24 hour period?

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that's how i do it.

my thought is if the ppm is constant, does it mean 1) the ppm is perfect 2) nute lockout and the plant isnt' eating at all

i'd rather see a slight ppm drop daily. and a slight pH rise.

rkymtnman said:

that's how i do it.

my thought is if the ppm is constant, does it mean 1) the ppm is perfect 2) nute lockout and the plant isnt' eating at all

i'd rather see a slight ppm drop daily. and a slight pH rise.

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That would all be based on what the water level is doing also.
Anything you see in PPM must be contingent on how your water level drops with it.
If you wanna make it easy...
1. PPM rise overnight with water drop = add plain water that night
2. Slight PPM drop with water drop = add back original solution strength or slightly stronger
3. MAJOR PPM drops overnight (50 or more) = Raise PPM's by 100 from where you were.
I think the right PPM is like you said, a range. You can be on the high side, low side, or right in the middle.