Medium pH Correction (Soil and Coco)

FluffsTravels said:

@Renfro and @DoubleAtotheRON Hey guys, both of you have mentioned in one thread or another about taking ph soil samples while the soil is dry. Is the Apera the only one that does this or does the Blue Lab do this as well? Is that the Apera 8500? I pick up my Blue Lab today but I may buy the Apera as well. Thank you.

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FluffsTravels said:

Gotcha. Thx. The Blue Lab is glass as well. I'll probably invest in the Apera as well. I believe this is the one you have in the pic: https://aperainst.com/ph8500-portable-ph-meter-kit-with-glp-data-logger-and-usb-data-output

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PH8500-SL Portable pH Meter/Tester for Soil (Direct Measurement), Equipped with LabSen 553 Electrode-Apera Instruments

The Apera Instruments PH8500-SL Portable Soil pH Meter/Tester, equipped with LabSen 553 Electrode, is designed for professional direct soil pH measurements.

aperainst.com

Cvntcrusher said:

Now when I do my big blooms and buds mix. ( I even upped my feed this time before testing) it comes out at 4.6......

If I add more feed, im just going to burn my plants. So do I simply just need to add ph up and get he correct PH?

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Renfro said:

Sounds like those nutrients are more acidic. Definitely buffer it up. A silica product could be used as the pH buffer, all or in part. Generally add the silica product first according to the label and mix, then start adding and mixing in the nutrients. See where that gets you, if you need more then use a pH up buffer. 4.6 is definitely too low.

I really don't like having to use a pH up buffer but whaddya gonna do?

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Renfro said:

Sounds like those nutrients are more acidic. Definitely buffer it up. A silica product could be used as the pH buffer, all or in part. Generally add the silica product first according to the label and mix, then start adding and mixing in the nutrients. See where that gets you, if you need more then use a pH up buffer. 4.6 is definitely too low.

I really don't like having to use a pH up buffer but whaddya gonna do?

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Renfro said:

Checking and adjusting the pH of your root zone in soil or coco is a very important part of growing healthy plants. Often you will notice nutrient deficiencies despite the fact you know you have provided an ample feed at an appropriate pH level. When this happens it’s generally either unhealthy roots or something going on in the medium locking out the nutrients. This could be a salt buildup or it can be a pH related issue.

Runoff testing is unreliable and bad information is often worse than no information. Testing soil pH should be done with a reliable digital soil pH pen. The cheap analog meters with the long metal probe are not good for pH measurements, they are good for moisture and that it. You should test all plants as they are not always the same, do not rely on one test for all plants. I am showing an example of a correction on a plant that was off and showing signs of nutrient uptake issues.

For starters the medium is DNA Mills Coco Cork and I have found it likes to be at 6.5 (I know). The plant is a Romulan cut that I was given and was tossed into flower right at flip as an afterthought. The normal feed pH is 6.5 and each 10 gallon pot gets 2.5 gallons of water, currently every 8 hours for most plants including this one (she drinks).

I tested the coco and the starting number of 5.74 (too low for me).

6.5 minus 5.74 = 7.26. I adjusted my next feed accordingly and it measured 7.25.

5 minutes after feeding I tested again and the pH is at 6.71.

2 hours after feeding it tested at 6.62

6 hours after feeding it tested at 6.38

It generally drifts back down some and ends up a little below 6.5. The following feed is then adjusted as needed to walk it onto target range. If the situation persists then the medium may have some sort of pH buffer that’s slow release and you may have to combat this the whole grow.

The soil pH meter can also be used to detect your daily pH swings and use them to your advantage. Lets say you want 6.3 - 6.8. If you water at 6.8 and it drifts down to 6.3 between the next watering then thats great! If you started at 6.5 not so much as you end up at 6.1 (seen it happen). Not everyone's soil will have a pH swing, more beneficial bacteria seems to make the pH move around more but it's good to know if you do and use it to your advantage.

Images in the following post. FWIW I meant to put this in the General Growing section but messed up lol.

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Cvntcrusher said:

I need help fellas. I'm just starting to learn ph ec tds etc.



I am running 4 photos. 1 of them is receiving fox farms trio. The other 3 are receiving big blooms and buds.

When I put my calmag and FFT into my gallon of water, mix it all up, calibrate my PH meter & test ph of the mix. Its 5.8 so thats good since I'm in coco.

Now when I do my big blooms and buds mix. ( I even upped my feed this time before testing) it comes out at 4.6......

If I add more feed, im just going to burn my plants. So do I simply just need to add ph up and get he correct PH?

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macsnax said:

I think a lot of growers don't realize how drift works in a solution, especially if it's fresh made. The longer it sits the more it balances until it's stable. It causes them to compensate in the wrong way. There's a lot more to it though, depends on the nutrients, base water, temps, etc. I've been running the floraflex line lately and it is the most ph stable nute I've ever seen, whether ph'd right away or tomorrow.

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Dapper_Dillinger said:

Hello friend where can i find more info as a well respected source of mine also uses these nutrients and in considering making the switch from foxfarm cultivation nation 2part soluble

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