New Grower ph control info?

[bgrt]

hi i am probably missing a blatantly obvious sticky but i cannot see it
and i cannot search for "ph" as it is too common/small of a term.

can someone explain or point to me to an article on the basics of ph control?
i have just received my first ph meter just a simple pen ph hydrotester with glass electrode etc. i think i have had a ph problem causing a lockout and had to wait for an order for a few weeks so im wanting to correct that and to know how to properly ph my nutes for feeding etc.

i am growing in soil and have a bottle of ph up and down, calibration fluid 4 and 7
and only a small sachet of storage solution that came with the pen. can i use one of these others to store in safely? or will that degrade accuracy etc.
i will be using general hydro 3 part nutes and tap water which i havent tested yet.
i hear the terms runoff etc and have a basic idea of what to do but it is only ever mentioned never explained so sorry if it seems stupid or arbitrary.

just dont want to fumble through and break the pen and be waiting another few weeks uselessly.
cheers

 

[AndyBotwin]

All the company literature I've seen says to only keep the probe in storage solution, but I've read where many use the 7 calibration and have no problems. What you want to avoid is storing it in distilled water, which will apparently damage the probe over time.

I test runoff by pHing my solution to something middle of the road like 6.5. Then I water until I get drops coming out of the drainage holes, and I collect that fluid and test it. I think the first drops are most accurate as they show you exactly what affect the soil has on the water, but the more that comes out you're going to naturally see it drift towards the same pH as the water coming in. I use a small pitcher and I know roughly how much each pot takes before it starts draining, so it's pretty easy to do all this. If I watered with 6.5 and my runoff was 6.3, I'd figure that my soil pH is somewhere around 6.2. So the next time if I want to bring that up I may water with 6.7 until my runoff comes up to exactly where I want it. It'll move around some depending on the plant and what stage of growth it's in, but you can keep it within range fairly easily with some practice.

 

[namvet]

Check out www.growery.org then fill in ther search box for soil ph.

 

[bgrt]

thanks andy illl give that a shot later on and look for some storage solution i just couldnt find it on the site i got everything else from.. also im going to transplant, how would you work out the soilmix's ph beforehand.
just drench everything to get a huge amount of runoff(ill need about 18 gallons made up)? or is there a simpler way, taking a small sample and judging runoff on that etc, just seems like that might not be an accurate way and is all i can think of.

cheers namvet checking that out now

 

[AndyBotwin]

thanks andy illl give that a shot later on and look for some storage solution i just couldnt find it on the site i got everything else from.. also im going to transplant, how would you work out the soilmix's ph beforehand.
just drench everything to get a huge amount of runoff(ill need about 18 gallons made up)? or is there a simpler way, taking a small sample and judging runoff on that etc, just seems like that might not be an accurate way and is all i can think of.

My usual procedure is to fill a pot with soil and drench it with a pHed myco solution a couple of days before planting. I test and record that runoff since it will likely vary between pots unless everything was mixed perfectly. And if you find that the soil is way off you can add lime or take other action before you have a seedling in the medium.

You can test soil by making a slurry with some distilled water, but like you said, that's such a small sample size that I don't think it's reliable.

 

[bgrt]

ill have a go at that tonight. i have some "garden lime" which i bought last year but never used as i wasnt sure it was dolomite lime which everyone seems to talk about. is this any use do you or anyone think?

"j. arthur bowers garden lime soil acidity regulator, neutralises excess soil acidity
analysis: screened limestone. neutralising value 45%. total passing through 150 micron sieve 20%"

i cannot find dolomite lime so far anwyay unless this is it or it has another different name over here.
looked like what people are usually recommending but i had no visible problems or need to use it last grow so never bothered.

also i ph'd the nuted water to 6.5 and the runoff was consistantly 6.2 across all pots, so should my ph be about 6? is this crazily low. anything i need to do immediately or should i just water with ph 7ish water next time.



EDIT

i made up a big batch of soil for the final pots and tested one pots worth, ran 6.5 water through and tested runoff at 5.7.

should i add that garden lime to bring it up to 6.5 ish? im still unclear if this is even the right thing. might be too slow acting etc.
or can i just ph water using ph up at a higher value to change this enough before planting?

sorry just im still not too sure of ph etc.
im hoping to plant them tonight is all i know its a bit of a rush but i have to go away for a few days and would like to have it done.

 

[bgrt]

my tap water is around 8. would this do even?..
forgive the triple post just looking for some info

 

[gooseberry]

bgrt,
I'm not that knowledgeable about the growing stuff, but have probably forgotten more about pH than most people will ever know, please bear this in mind when reading this. The usual storage solution for a pH electrode (usually a combination electrode consisting of a glass electrode and a reference electrode in one) is a saturated solution of KCl (potassium chloride), at least this is the case for most that woudl be used in e.g. a water testing lab. The saturated KCl solution is also often the same solution that the electrodes are filled with, although I think that some manufacturers may recommend other solutions for storage, such as a pH 7 buffer. Whatever you use, I think it needs to be concentrated enough not to dilute the electrode filling solution too much.
I would suggest that it is not really worth worrying about a small diference in the measured pH value (e.g. a differenc eof 0.1 pH units) unless you are making very high quality measurments and are absolutely sure that your electrode is performing correctly. A simple quality control measure might be to take a measurement of the pH of your tap water regularly, as it is commonly quiet consistent over time, and could indicate any poor electrode performance before it becomes apparent otherwise. However, a difference of 0.5 pH units, which might not sound like a big deal, is actually 3 times more (or less) acidic (depending upon whether the difference is down or up).
I would be inclined to add some lime to your soil mix, although you may want to leave it to site for a while (wet perhaps?) for the lime to take effect before you plant in it. You mentioned dolomite, I'm not sure why but this is just a form of limestone that contains quiet a lot of magnesium instead of almost all calcium. pH 5.7 is probably around 6 times more acidic than you are aiming for. Watering with pH 8 water (e.g. your tap water) would almost certainly be a step in the right direction, but might not be enough to give you the soil pore water pH that you are after.
You do seem to be heading in the right direction (adding lime, using higher pH water) so I'm sure you will get things just how you want them before too long.

 

[bgrt]

hey cheers for the info atleast i know im not going in the wrong direction.
:thumbs:

i put off replanting anyway and added a little lime, have the pots watered. ill just water again and see if theres any change monday atleast then ill see how long it should take to get into an acceptable range and maybe the lime will start to help too.

 

[bgrt]

can someone help me with something. i have been trying to get the ph of the soil i hope to plant into down to an acceptable level so i can transplant but im not sure if its going to take a huge amount of time. i watered the pots that were made up last week with 8.8 water and they come out at around 6.2 so it must be pretty far off very aciditic. i need to transplant as they are getting rootbound or will be very soon. so should i transplant and fix over time or start again with new soil or wait? ihave no car so it will take me time to be able to get soil to my house days maybe a week or more delivery or finding someone i can trust to come buy soil/ pick me up... if i dont get an answer ill head to the infirmary but seems more like a simple thing than a plant problem.

think i did a similar watering last week and similar reading so i dunno if its changing much.

also im thinking of just transplanting and fixing over time... but correct me what would you do?