Ppm calculations for soil...for dummies

Nutrients
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Hey guys/gals hope everyone is enjoying a successful grow :call_me_hand:

Trying to calculate my ppm rates for my next feed. I have read through countless hours of posts here on the forum and every time i think i have it down my runnoff numbers tell me something different :face_with_spiral_eyes:

I know the girls will consume at different rates depending on many factors including stage of growth, environment, health, strain and so on.

That said, just looking for a general calculation you all use.

Based off of runnoff numbers(and previous feed/runnoff) how do you calculate(in ppm):

  1. How much she ate
  2. How much to feed at next watering

Probably wake and bake induced, but im coming up with some #'s this morning that make no sense :crazy_face:

Thanks

:metal:

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I dont usually check my ppm. Always read to maintain 1000 ppm for runoff.
Would assume you subtract runoff ppm from ppm going in. I have a system that works for me but everytime I try changing something it goes south and I end up going back.
@Lostgirl is the ppm and #'s expert.

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This is for hydro but somewhat applicable.

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I know lostgirl is great with the numbers(shes actually helping me on a particularly troublesome grow ive got going on right now)and alot of what i thought i had figured out was drawn from many of her posts/replies. I just hate bothering her knowing shes always really busy guiding others. And i like to figure this stuff out on my own as much as possible.

Figured if i could get solid base calculations that my old a$$ brain could comprehend, id be good lol

Thanks

:metal:

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Thank you @Myfriendis410 ill see what i can pull from that chart for my situation. Just thinking if i could start with solid base calculations for the 2 items above, id be on track to more easily calculate my feeds going forward.

Was reading through a bunch of posts this morning and one in particular really threw me off and had me coming up with numbers that made no sense(though from a member who i know has great knowledge).

Thanks

:metal:

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What exactly is confusing you? From what I read you had some whacked out numbers today on your runoff yet I don’t see the numbers or the scenario.

Tell me how I can unstuck ya?

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Hey @Lostgirl im trying to figure out how you all come up with the following

Based on trying to obtain 1000ppm runoff

Thought i had it figured out(mostly from reading many of your posts/replies) but was reading some posts this morning(not yours) that threw me off. And i have not been able to find anyone who has actually laid these two items out in a simple calculation. Im really anal with numbers so im nuts today :crazy_face::crazy_face:

And yes i came out with some unfavorable runoff numbers on my other post after my first post flush watering so im just trying to calculate for next feed and want to confirm im on the right track. The numbers weren’t completely horrible but the condition of the plants ARE horrible. Just trying to dial in #'s for next feed/water

Ill post over there after my next watering.

Thank you

:metal:

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@Lostgirl
To add to that and the reason for my confusion.
My runoff #'s from my first post flush feed
Plant 1 - 1210ppm
Plant 2 - 1540ppm
Plant 3 - 1340ppm
Plant 4 - 1080ppm
Plant 5 - 1200ppm

So i know i want to go in with a lower ppm next feed on 4 of the 5. So while trying to calculate(and wanting to confirm i was doing it correctly) i came across a post by a very successful knowledgeable member here that said:

“If my runoff is 1000ppm or over, they will get ph’d water and cal mag at 150 ppm. If it’s say 500 at a check, next feed would be 800 and check runoff. I know mine eat 300-350 ppm between feeds, something you just have to learn to judge by experience. So going in at 800 , add the 500 from last check, that’s approximately 1300. Minus the 300 they eat each feeding, that’s 1000 runoff, if all goes well”

So if this is correct(or the first part of that), id be just watering with no nutes next time for 4 of the 5? Or should i figure out how much they ate and base my next feed on that(which is what i thought was correct)?

At the same time ive read here many times that you dont want to go with drastic changes in feed rate such as feed, water, feed, water due to the plant needing to adjust its processing of nutes(or not).
Baaahhhh so confused :crazy_face::crazy_face:

Anyway, still just looking for everyone’s (anyone’s) calculation for those two items. Even if my runoff was off after, at least id have a base calculation to start with and then could adjust from there.

Thanks

:metal:

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This is easy. Nevertheless I’m heading to the grocery store. When I get back I’ll help you out with this
:v:

On the 4 different runoff numbers that you have above

What was the feed intake total PPM that you fed them when they ran off these numbers?

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Normally folks just water with plain water until the runoff hits 1,000 ppm then resume supplements. It’s pretty easy. Also; my experience if using soil is that anything under 2,000 ppm (NACL scale) is not harmful to plants. If in soilless then closer to 1,000 ppm is recommended.

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@Lostgirl
Im going to post those numbers on my other thread. Trying to keep this one as a “how to calculate ppm” thread.

I dont want to cross post as i know how annoying that is :crazy_face::crazy_face:

Thank you!!

:metal:

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@Metalheadfred: This spreadsheet may be just what you’re looking for.

To estimate how many ppm a plant ate (Appetite):

Appetite = Previous runoff ppm + Latest feed ppm - Latest runoff ppm

So, for example, if a plant’s runoff measured 400 ppm previously, the latest feeding added 600, and the runoff from that feeding measured 300, the plant absorbed (400 + 600 - 300 =) 700 ppm. Divide by the number of days to estimate the plant’s daily uptake.

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Thanks @Venturi thats exactly what I was looking for :+1::+1:

Will checkout the spreadsheet as well :sunglasses:

:metal:

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