What is PROPER way to test run-off ph?

[Max Frost]

Most welcome. :)

I have used colorimetric/titration kits, but as Max says, it's difficult to take a reading if nutrients have changed the color of the water much. I now have a Hanna meter.

I do also test plant sap pH, with a goal of achieving 6.4, and for that I use litmus that comes on a roll. I'll have to search for it, I got it on Amazon.

Now THAT sounds interesting for sure, Seamaiden! Can you give more info on "sap pH" please? I've never heard of doing it and would like to know whatever you can share on it. Thank you in advance!

Best,

Max :wacky:

 

[Seamaiden]

I'm still in a learning phase, but based on my reading, typically a sap pH of 6.4 is the sweet spot, and when used in conjunction with Brix readings is very helpful in determining how well a plant is doing. How to adjust that plant sap pH is something I definitely do *not* have down well enough to explain. :o

 

[Lazerus00]

My experience is different, so I do a slurry test. Very simple and really only takes about 10mins or so. I take my samples of media from the root zone, then mix them into a water sample I've already tested for pH and EC. I let that slurry sit for about 7mins, then test. I've found this is a much more accurate method, and better for *me* with regard to solving problems.

What's most important, however, is to make certain that whatever you're using to test parameters is itself accurate.

Okay so when I take soil out of the root zone i am worried i might damage the roots..Sorry if I sound stupid, i am new to this as it is my first grow...I did the slurry test as you suggested but really only took soil from about 2 inches down on diff sides of the pot...p.s. i posted the results in Tnelz thread about whatever...not sure what "good" results are so far as ppm...any help would be much appreciated as i am having some leaf issues and am thinking it might be pH related..also pics posted in tnelz thread

 

[Seamaiden]

Okay so when I take soil out of the root zone i am worried i might damage the roots..Sorry if I sound stupid, i am new to this as it is my first grow

There will be some damage, there's just no way to get around that. But if the plant is healthy, has a good root system at least, it shouldn't hurt. If the plant is unhealthy, IME it's better to figure out what's going on instead of wasting time guessing. Knowing what's going on in the root zone either gives you your answer, or eliminates that as a possibility (when troubleshooting).

.I did the slurry test as you suggested but really only took soil from about 2 inches down on diff sides of the pot...p.s. i posted the results in Tnelz thread about whatever...not sure what "good" results are so far as ppm...any help would be much appreciated as i am having some leaf issues and am thinking it might be pH related..also pics posted in tnelz thread

"Good" is a relative term. First, we'd want to know a few things. Is your media really soil? Are you using any organic feeds or amendments that may mess with readings (organic molecules cannot be read accurately using EC, from which ppm/TDS readings are calculated. An example here would be molasses, which tends to drive those readings up crazy high).

"Good" pH is much easier to know, see and correct. If you posted in Tnelz's thread, you're going to get really good help there. Otherwise, a link is helpful. :)

 

[newbie1]

There will be some damage, there's just no way to get around that. But if the plant is healthy, has a good root system at least, it shouldn't hurt. If the plant is unhealthy, IME it's better to figure out what's going on instead of wasting time guessing. Knowing what's going on in the root zone either gives you your answer, or eliminates that as a possibility (when troubleshooting).

"Good" is a relative term. First, we'd want to know a few things. Is your media really soil? Are you using any organic feeds or amendments that may mess with readings (organic molecules cannot be read accurately using EC, from which ppm/TDS readings are calculated. An example here would be molasses, which tends to drive those readings up crazy high).

"Good" pH is much easier to know, see and correct. If you posted in Tnelz's thread, you're going to get really good help there. Otherwise, a link is helpful. :)

That will explain why my PPM is so high :) from 700 - 938 PPM. Im using Bio Grow ( Mollasses based nutrient) . Does this mean everything is fine ? as i thought id overfed them. They seem fine even though my run off Ph Was on 2 plants as low as 4 :-( Do Organic nutrients play with the ph the same way ? definitely going to try the slurry test. Thanks for the info @Seamaiden.

 

[Seamaiden]

I'm not sure I fully understand your questions. :)

 

[newbie1]

I'm not sure I fully understand your questions. :)

You were saying in an earlier thread that molassis based and other organic nutrients give inaccurate PPM readings. I was wondering do the organic nutrients also effect the Ph readings. My run off Ph on my 5 plants phd from 4 - 5 which seems very low. Although my plants look really healthy, when i watered them i watered for the first time with water phd to 6.5 and 2 days later they are looking very happy. Thanks for your reply @Seamaiden :)

 

[Seamaiden]

I was wondering do the organic nutrients also effect the Ph readings.

Ah! Gotcha. No, you should be able to achieve as accurate a pH reading with organic fertilizers as salt-based.

I'm pretty sure you've commented on trying slurry vs run-off method of pH management. There are *many* people who are well able to recognize and resolve pH-based issues using the run-off method, I just prefer slurry because I wasn't able to well ascertain the scenario using that method. In other words, try both methods, see what works best for you in your scenario. :) Lookin' good on the farm!

 

[Purpletrain]

The proper way to do runoff IMO is having your water your pouring set @ 7.0 slowly pour it in and once it starts pourng out test ph and keep testing ph until your runoff is @ 7.0
Mark the numbers down and figure out what the average is
Doing a slurry test is ok for new soil mixes but not ok for soil that is being used in a persons grow ..
It may be off pending on where sample was taken taking soil from 4 inches on top can be a mile off from what ph is @ the root zone the most crucial area
If you take it from 6 - 8 " below top crust then again it can be way off from other parts of the container
So i think the best way is to very slowly saturate your soil allowing all soil to get drenched then once it starts pouring out you keep testing runoff until it starts to come back to what you pouring in
the first runoff is not accurate due to water finding the easiest route to get out
Goal is slowly saturate medium

 

[newbie1]

Ah! Gotcha. No, you should be able to achieve as accurate a pH reading with organic fertilizers as salt-based.

I'm pretty sure you've commented on trying slurry vs run-off method of pH management. There are *many* people who are well able to recognize and resolve pH-based issues using the run-off method, I just prefer slurry because I wasn't able to well ascertain the scenario using that method. In other words, try both methods, see what works best for you in your scenario. :) Lookin' good on the farm!

Thanks Sea :) I watered the 2 with the lower ph tonight and run off was 5.9 so its risen a little, i done another slurry test and one plant soil was 5.9 and the other 6.1 I had flushed them to a nice run off with tap water ph 7.5 A bit of leaf curl developed on one of them but hopefully issue will soon be resolved. I like the slurry method so far. :-)Thanks for your help much appreciated and thanks for compliment on garden :)

 

[Seamaiden]

When *you* succeed, *I* succeed. So, go succeed.

 

[Bannacis]

When *you* succeed, *I* succeed. So, go succeed.

Hey I know a guy name Ceed... So don't be surprised I pass on your recommendation there...lol

 

[MendoAdome]

Most welcome. :)

I have used colorimetric/titration kits, but as Max says, it's difficult to take a reading if nutrients have changed the color of the water much. I now have a Hanna meter.

I do also test plant sap pH, with a goal of achieving 6.4, and for that I use litmus that comes on a roll. I'll have to search for it, I got it on Amazon.

Its not a good idea to harm your plants unneccesarily. If you go with a slurry strain it through a fine micron filter. to prevent damaging your probe. Hannah probes are not that well made and have a tendency to dift more over time. Get a Bluelab.

Test runoff simply by carefully placing the probe in the saucer or table. Let stablize and your done. Make sure that the water has not been standing in there too long. Your best bet is to get a digital pH soil tester from blue lab. EC is done the same way. Dont even mess around with ppm if you dont have to.

 

[MendoAdome]

You were saying in an earlier thread that molassis based and other organic nutrients give inaccurate PPM readings. I was wondering do the organic nutrients also effect the Ph readings. My run off Ph on my 5 plants phd from 4 - 5 which seems very low. Although my plants look really healthy, when i watered them i watered for the first time with water phd to 6.5 and 2 days later they are looking very happy. Thanks for your reply @Seamaiden :)

you should be between 5-6 not 4-5 looks like you switched into bloom and your not getting enough K. GOod day

 

[heisen]

the most accurate way is to send sample to a farmers co-op and they will test it for you for next to nothing.This is the absolute best way or if you are buying a quality soil they are usually good to go out of the bag.checking runoff of dirt is a big ass waste of time plain and simple.It will make you feel like your doing something awesome but in reality the results you get will cause you to over or under compensate and fuck up your plants.
The slurry test is the next best thing.
Ive grown some monster plants in regular ass fox farm just using nutes and mixing half strengths of whats on the bottles.If you look at over 80 percent of the grows on these forums most plants are burnt the fuk up 5 weeks into flower and people just think its normal and keep on with it.Less is always more when it comes to growing in containers.plants in soil have a pretty wide PH range they can thrive in.as long as they have good light and not over or under fed they will do good.

 

[GrowVT]

My experience is different, so I do a slurry test. Very simple and really only takes about 10mins or so. I take my samples of media from the root zone, then mix them into a water sample I've already tested for pH and EC. I let that slurry sit for about 7mins, then test. I've found this is a much more accurate method, and better for *me* with regard to solving problems.

What's most important, however, is to make certain that whatever you're using to test parameters is itself accurate.

Sorry to dig up an old thread but I just can't seem to find an answer. How do you take a soil sample from the root zone without damaging the roots in 3 or 5 gallon smart pots? I guess in any pot for that matter.

 

[Nukesrt]

Sorry to dig up an old thread but I just can't seem to find an answer. How do you take a soil sample from the root zone without damaging the roots in 3 or 5 gallon smart pots? I guess in any pot for that matter.

ever get an answer?

 

[Goodthingsgrow]

Max you're gonna get the same reading whether it's strained or not...

The purpose of straining the slurry is to remove the heavier solids to avoid gunking up the test equipment's probe
or the PH pens conductivity electrode

Sorry. Off topic...waayne, love the profile pick dude!

 

[JWM2]

ever get an answer?

Grab a core sampling tool off Amazon for $15-30. You can pick up a soil test kit also for $25 right now that lets you send in your sample for professional lab results. I’ll be posting some lab results here shortly in a new thread once I get results back from the lab.