EC - us/cm - PPM guidelines

Nate_in_AK · Apr 18, 2020

Google and forum searches are leaving me uncertain on this. I found this chart on royalqueenseeds.com:

Since my plants are auto's, I can't pinpoint when they switched to flowering exactly, but I believe it was very early April -so let's say I'm going into week 3 of flowering.

I am reading 750PPM and 1500us/cm (1.5EC). From what I have read so far, this indicates my nutrients and salt are probably pretty well balanced, and I just need to up the nutrient density.

This this chart look about right? Can EC and PPM be managed individually?

Dirtbag · Apr 18, 2020

Those numbers all seem high to me. I rarely go over 1.5 ec/750ppm if ever.

AnselAdams · Apr 18, 2020

Nate_in_AK said:
Google and forum searches are leaving me uncertain on this. I found this chart on royalqueenseeds.com:
View attachment 963374

Since my plants are auto's, I can't pinpoint when they switched to flowering exactly, but I believe it was very early April -so let's say I'm going into week 3 of flowering.

I am reading 750PPM and 1500us/cm (1.5EC). From what I have read so far, this indicates my nutrients and salt are probably pretty well balanced, and I just need to up the nutrient density.

This this chart look about right? Can EC and PPM be managed individually?

For me, that seems about right. After i hit 1100-1150, i start bringing it back down by extracting an extra 5 gallons of rez water and increasing the RO replacement to normal levels. I do that with each rez top-off (about every two days) until harvest. If i go over 1150 I do a 5 gallon rez change out for fresh RO water right then. It works for me!

Happy Growing

p.s. Oh! and you can stick a pin at 4 weeks. I have grown 4 different autos and everyone started to flower between week 4-5 from germ. Just my newbie track record to date.

cemchris · Apr 18, 2020

Certain strains can take up to 1200 ppmish no problem but take that with a warning. If you miss a watering or they dry you will prob fry your plants with no coming back. Anything above 800 ppm is where you will run into problems with nute sensitive plants like blueberry crosses and certain diesels. Keep it under that to be safe unless you know what you are doing and even then I wouldn't go over that. More nutes don't equal more qual or yield.

AnselAdams · Apr 18, 2020

cemchris said:
Certain strains can take up to 1200 ppmish no problem but take that with a warning. If you miss a watering or they dry you will prob fry your plants with no coming back. Anything above 800 ppm is where you will run into problems with nute sensitive plants like blueberry crosses and certain diesels. Keep it under that to be safe unless you know what you are doing and even then I wouldn't go over that. More nutes don't equal more qual or yield.

I totally agree. I am constantly looking for ways to reduce my numbers and the number of nutes i use to get to harvest. My target has always been 8-900 ppm. I only hit 1100 on the days that i add cal-mag or enzymes. Then i watch to make sure it consistently drops over the next week. I don't worry about it since i only add both twice during the entire 12-16 week grow. I am growing a pair of Auto Train Wrecks in a 40gal rez so I have a lot of flexibility. Once they get going they pair drink 3-5 gallons a day, so i will know quickly if something goes wrong. In a smaller rez or with more occupants, you won't have a lot of time to correct a mistake.

to Cemchris' point; different strains behave differently. I have been growing from the same batch of seeds for over a year now so I am pretty comfortable with how they will behave.

MIMedGrower · Apr 18, 2020

In my experience weed grown with more the minimum the plants need tastes a lot better than weed grown with high levels of nutrients regardless if the strain can handle it.

My ec stays 1.0-1.5. I have had 1/2 pound plants indoors with those numbers.

Moshmen · Apr 18, 2020

AnselAdams said:
For me, that seems about right. After i hit 1100-1150, i start bringing it back down by extracting an extra 5 gallons of rez water and increasing the RO replacement to normal levels. I do that with each rez top-off (about every two days) until harvest. If i go over 1150 I do a 5 gallon rez change out for fresh RO water right then. It works for me!

Happy Growing

p.s. Oh! and you can stick a pin at 4 weeks. I have grown 4 different autos and everyone started to flower between week 4-5 from germ. Just my newbie track record to date.

Mine too on the auto week 4-5 fir sure

Mospeada · Apr 18, 2020

Depends on the medium...Hydro is the most efficient out of all of them. It can be up to 3 times more efficient so a hydro grower should in theory always use less nutes. I honestly can't get my solution above 400 ppm without seeing a ppm increase the next day...They easily eat between 100 - 200 ppm of Ca but that's always gone by the time I take my next reading. So all the nutes except Ca usually add up to around 300 ppm using Ro water and then 100-200 ppm of Ca.

Another thing the chart doesn't mention is what water is being used. Hard water can easily add up to 300 ppm if not more though the avg is usually 200.

Nate_in_AK · Apr 19, 2020

Interesting variations in feedback, but all helpful to further my education. I think I'll keep things where they are for now based on the responses. PPM and EC have been stable and the plants are doing better than I deserve. Still confused about the difference between EC and PPM exactly.

EC = Electrical Conductivity, and is used to indicate the potency of the salts in the water.
PPM = Parts Per Million, and is used as an indicator of the amount of non-water material in the water. (nutes)

Is this accurate, or am I confused?

Nate_in_AK · Apr 19, 2020

MIMedGrower said:
In my experience weed grown with more the minimum the plants need tastes a lot better than weed grown with high levels of nutrients regardless if the strain can handle it.

This is fascinating feedback. Can anyone else offer observations on this?

AnselAdams · Apr 19, 2020

Mospeada said:
Depends on the medium...Hydro is the most efficient out of all of them. It can be up to 3 times more efficient so a hydro grower should in theory always use less nutes. I honestly can't get my solution above 400 ppm without seeing a ppm increase the next day...They easily eat between 100 - 200 ppm of Ca but that's always gone by the time I take my next reading. So all the nutes except Ca usually add up to around 300 ppm using Ro water and then 100-200 ppm of Ca.

Another thing the chart doesn't mention is what water is being used. Hard water can easily add up to 300 ppm if not more though the avg is usually 200.

during flowering, I see the ppm rise the next two or three days, however i figured out that if i wanted to actually see the ppm reduction, i would need to add fresh RO water to the rez and take it back to the "full" mark. I usually top off every two days and i don't begin to feel i have an issue unless i add fresh water and the ppm DOES NOT drop. That has only happened once, with my second grow. I had F'd up and found out that nute lockout had occurred and so only a huge rez water change could dig me out before they fried.

Happy Growing

Mospeada · Apr 19, 2020

AnselAdams said:
during flowering, I see the ppm rise the next two or three days, however i figured out that if i wanted to actually see the ppm reduction, i would need to add fresh RO water to the rez and take it back to the "full" mark. I usually top off every two days and i don't begin to feel i have an issue unless i add fresh water and the ppm DOES NOT drop. That has only happened once, with my second grow. I had F'd up and found out that nute lockout had occurred and so only a huge rez water change could dig me out before they fried.

Happy Growing

Yeah every growers conditions are different on top of different strains. I use to change my res weekly when I first started. You're using enzymes and beenies in your grow aren't yah? That adds to the count quite a bit from what I've seen in other grows but can't speak from experience. I'm still trying to get the balance right myself but I've gotten close to having an entire feed schedule for the particular strain I grow, enough for me to be confident I can go through half of flower without changing my res or having a drift higher than 100ppm for longer than half a day.

Mospeada · Apr 19, 2020

Here's a real time snapshot of what I see with ppm and my feed. Atm Ive been pushing the PK + Mg. Like always the plants aren't taking the extra and my ppm is going up. From 350 steady to 380. This isn't including calcium.

The first photo is the res ppm...second the feed I'm about to add. I cut back on PK for this feed for a 5-5-5 ratio. Loaded up heavily on the calcium. About 300 ppm...more than two thirds of the total solution.

About to take another res ppm reading in an hour after the nutes cycle through. The calcium usually is gone within a couple of hours so I wouldn't be surprised if there is a drop in ppm. It's still a fuck load of guess work I would love to get a true break down of my solution.

Mospeada · Apr 19, 2020

Mospeada said:
Here's a real time snapshot of what I see with ppm and my feed. Atm Ive been pushing the PK + Mg. Like always the plants aren't taking the extra and my ppm is going up. From 350 steady to 380. This isn't including calcium.

The first photo is the res ppm...second the feed I'm about to add. I cut back on PK for this feed for a 5-5-5 ratio. Loaded up heavily on the calcium. About 300 ppm...more than two thirds of the total solution.

About to take another res ppm reading in an hour after the nutes cycle through. The calcium usually is gone within a couple of hours so I wouldn't be surprised if there is a drop in ppm. It's still a fuck load of guess work I would love to get a true break down of my solution.

Fell alseep lol....anyways after that last feed cycled through the ppm is three less than before the feed .

AnselAdams · Apr 19, 2020

Mospeada said:
Here's a real time snapshot of what I see with ppm and my feed. Atm Ive been pushing the PK + Mg. Like always the plants aren't taking the extra and my ppm is going up. From 350 steady to 380. This isn't including calcium.

The first photo is the res ppm...second the feed I'm about to add. I cut back on PK for this feed for a 5-5-5 ratio. Loaded up heavily on the calcium. About 300 ppm...more than two thirds of the total solution.

About to take another res ppm reading in an hour after the nutes cycle through. The calcium usually is gone within a couple of hours so I wouldn't be surprised if there is a drop in ppm. It's still a fuck load of guess work I would love to get a true break down of my solution.

Here is something you might try. It has worked well for me and some others on the Farm.

For each of your additives, take a one gallon jug full of fresh RO water and get the ppm count. Then add the dosage you plan on using per gallon, shake well and wait 5 minutes, shake again and get another ppm reading. Then write that info on bottle 10mil/227ppm. With that information you can obtain fine grain control of your additives and thus your ppm count. You will get real good very quickly at determining how much you can feed of any one additive and remain below your target ppm.

Happy Growing

Mospeada · Apr 20, 2020

AnselAdams said:
Here is something you might try. It has worked well for me and some others on the Farm.

For each of your additives, take a one gallon jug full of fresh RO water and get the ppm count. Then add the dosage you plan on using per gallon, shake well and wait 5 minutes, shake again and get another ppm reading. Then write that info on bottle 10mil/227ppm. With that information you can obtain fine grain control of you additives and thus your ppm count. You will get real good very quickly at determining how much you can feed of any one additive and remain below your target ppm.

View attachment 963567

Happy Growing

I do take a reading for each individual additive but didn't think of putting ml/ppm ratio on there which would be super handy.

Anyways it's been more than 14 hours since I took the last reading. In that time there's been no calcium in the solution but at least it looks like some of the extra PK + Mg I added a couple of days ago is finally getting used up by the plant. Still off my target ppm of 350 but after one more 5-5-5 feed I should be back to no drift between readings.

EC - us/cm - PPM guidelines

EC - us/cm - PPM guidelines

Nate_in_AK

Dirtbag

AnselAdams

cemchris

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EC - us/cm - PPM guidelines

EC - us/cm - PPM guidelines

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AnselAdams

cemchris

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Moshmen

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Nate_in_AK

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