Proper PPM ranges?

Hey folks, i just neasured the runoff for each of the girls:
Blueberry Auto: 648
Pineapple Haze: 384
AK47: 542
Sour D: 710
Strawberry: 581

@bob31 @Countryboyjvd1971 @Covertgrower @dbrn32 @Ray4x @SmoknGranny and anyone else…
What are the proper ranges? Im using FFOF


I’m no help with this question. I’m still trying to learn about the “technical” stuff as I call it :blush:


I don’t know the numbers off the top of my head, but I think the ff feeding charts have recommended ppm. I’m sure some of the members using it can help break them down, but I don’t measure for the plants I use it on and not very familiar.

This help? I don’t have a tds meter… but I found this on their website. I was unable to copy and paste, so a screenshot will have to do.

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I havent given any nutes yet so i think i neec the pre nute ppm chart. I have GH nutes


More info, dude. You might want to fill out a support ticket. I am assuming based on the numbers that you are in flower now. I would call that depleted. Take a small sample of unused soil and do a runoff test of that for comparison.


Still vegging. Seeds dropped Sept 7

Ooh, that seems low…

It might be time to start em on the program. 1/4 strength to start.

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Im testing some unused soil and the ppm on that is like 211???

I agree, at over 4 weeks and seeing your plants in the other thread, they’re probably ready for a light feeding. Your ppm looked a little low, but every grow is a little different. Depending on temps, strain, even water quality, there is no exact number that will apply to everyone.

Plants look happy though, so maybe 1/4 to half strength from manufacturer recommendations. See how they react, and you can adjust from there.


This is a job for @garrigan62 … if anyone can help with ppm it’s this guy … good luck :four_leaf_clover:


The proper PPM range will depend on the nutrient. The max PPM a plant can take without experiencing “nute” burn depends on what the PPM is made out of. For example, a nute with very low nitrogen might be able to have a very high PPM and not burn the plants, however a nute with a lot of nitrogen might need to have the PPM kept relatively low. Another example is that very high levels of certain minerals, like calcium carbonates and calcium bicarbonates and silicates can cause PPM to read very high, but this might not burn or cause damage to your plants at all.

Happy growing,



@MacGyverStoner Thanks for the info!!! I have GH nutes and will be following this feed schedule
The ppm ranges on the left are the reccommended ranges to test the water with a TDS meter before you feed?

Its been warm in my tent since im in a shed. I think i got it figured out. Add nutes to water, then test with TDS meter to make sure ppm is in range for correct week? I did it with 1/4 of reccommended nutes, and tested and got very low, like 200-300ppm. I did one gallon at 1/2 nutes and got to around 700. Then I did a gallon at full nute and got closer to the >1000ppm, which the GH feed chart says is ok for early growth ppm range… please correct me or stop me if im in wrong stage or week!!

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Yes, this looks correct.



Agreed. I don’t use those nutes or charts, so like I said I can’t exactly tell you from experience l. I think some of them show mixture ppm, some runoff ppm, and you may be even able to get both?

I’ve been told and read that when using the synthetic nutes that the manufacturer data is often more than needed. And needs to be watched especially closely when using soil that’s already amended. I’m not sure how true that is, but it sounds reasonable. Yet others like @Countryboyjvd1971 seem to use full dose per schedule and do great. So maybe he could weigh in too.

Personally, I have a hard time giving advice in this department. Especially if it’s not responding to a specific issue. I don’t have a lot of experience with the different lines, and the one I use was stolen from another forum a few years ago. I pretty much just follow it and adjust as the plants suggest.

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Also, these PPM numbers, for the most part, are assuming you are adding to zero PPM R/O water. And so you might want to add the PPM of tap water to these numbers to know what number to look for when you test it with your TDS meter.

And yes, if you are already growing in a soil that contains lots of nutrients, you might want to be careful feeding at full strength as the nutes in the soil will add to the total PPM. This is where testing the run off to estimate the PPM in the soil would come into play, or testing the soil directly.



The ppm seemed low for FFoF

Introducing them to their nutrient program, it is always a good idea to err on the cautious side. It’s easier to add than it is to remove.

I thought it seemed low too @VelcroThumb. But I never measured it.

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I just read Robert’s procedure for measuring tds and ph of the soil. I have a question though. How do you get the soil from the 'root zone? I grow in 10 gal soft pots.