Dr. Bruce Bugbee

[Emilya Green]

lol. ok, I understand a whole lot better now. It doesn't matter that there are two different competing theories here on soil pH, because you don't take a stand on either one of them; you are simply relaying information. Got it. That way I can't argue with you, because you are just the messenger. The only thing you are adamant about is that you don't believe in the need to "drift", and by definition I will state that by that term I mean coming in at the low end of the pH usable range, at 6.3, and then letting the soil drift the pH through the entire range until you end up at or near the base pH of the soil.

Many gardeners add lime to their soil, to "sweeten" it. What does that term mean, sweeten? I will tell you... it means to raise up the base pH so that there is a range that the soil will go through if you come in low with nutes. It makes the soil more receptive to the nutes, and the plants grow better. One reason in a carefully controlled indoor container grow that this works so well is that by coming in at exactly 6.3 and relying on drift, is that you keep your nutrients within the usable range for the most amount of time, thereby making your nutes the most available as they can be.

You are doing the same thing sort of, because you are advising people to get rid of their drift, and to use the soil in another way, to lock down on the middle of the range, at 6.5 or wherever and just let the nutes work. In order to do your method I need to do slurry tests and add this or that to keep the soil locked down, in my method I close my eyes, throw in some lime and call it a day, knowing that I will have drift to the high end and I also won't ignore the low end.

All those cats and the various ways to skin them... it amazes me sometimes. Carry on with your lab experiment as it obviously works for you, and I will continue with what is in my humble opinion, a much easier method. Maybe we could compare man/hours involved in a typical grow someday, I think that would be enlightening.

 

[InTheShed]

Nothing is "locked down." Water at 7, water at 6, makes no difference to the plant in a buffered medium. And I'm not doing lab experiments, those have already been done by soil scientists. I read their writings and apply them to my plants. And I advise folks with plant troubles how to solve them. No harm to the plants. No lasers.

Where you and I disagree is the need to pH your nutrient solutions in a buffered medium, full stop. pH drift is something folks in DWC do. Pouring 7.0 nutes into your soil will not affect what the plant takes up, as what it takes up is determined by the pH of the substrate, not the liquid.

If you would like to post a link to a scientific website that indicates that it is necessary to pH your nutrient solutions in a buffered medium, or that the pH of the nutrient affects what the plants can uptake, I'd be glad to read it. In the meantime, you go your way and I'll go mine.

 

[FelipeBlu]

I learned something from this discussion. Thank you all.

 

[bruno12345]

Nothing is "locked down." Water at 7, water at 6, makes no difference to the plant in a buffered medium. And I'm not doing lab experiments, those have already been done by soil scientists. I read their writings and apply them to my plants. And I advise folks with plant troubles how to solve them. No harm to the plants. No lasers.

Where you and I disagree is the need to pH your nutrient solutions in a buffered medium, full stop. pH drift is something folks in DWC do. Pouring 7.0 nutes into your soil will not affect what the plant takes up, as what it takes up is determined by the pH of the substrate, not the liquid.

If you would like to post a link to a scientific website that indicates that it is necessary to pH your nutrient solutions in a buffered medium, or that the pH of the nutrient affects what the plants can uptake, I'd be glad to read it. In the meantime, you go your way and I'll go mine.

Perfectly written.

One thing we must consider is the resilience of this plant. This is not like a plant who only works on a small pH zone. Cannabis seems to thrive in pH of 5.0 to 7.0. If we take other pH resistant species, we could say 5.5 to 6.5 would be the optimal range.

I just open the tap, take my 7,2 ph water, low alkalinity, and water my plants.
After a few minutes, i do the pourthrough method and the pH is my soiless mix pH.

Its like a strenght game, where pH of the solution is thousands of times weaker than soil (or soiless) pH. But this depends on the buffering capacity of the medium (liming, organic matter, composition, base pH of the mix), alkalinity, nitrogen source etc. In the moment its watered, to 20.. 30 min later, the pH has completely changed, although some reactions may take an entire day or even more.

The slurry test shows it, you mix water with a piece of soil and the pH is the soil pH.

I dont believe its appliable to rockwool or coco growing, or is it?


Ive been using this technique of ammonium fertilizer.
When i do my earthworm casting tea, it has an alkalinity of near 150PPM. I counteract it with ~20% ammoniacal nitrogen.
Im using the pourthrough method for monitoring pH, not the more accurate, but is used alot in horticulture practices and also extremely easy to do, and when you take constant records it can show you the trend of pH. I do it almost every watering as it shows how my nutes are doing, and how my pH is drifting.

I learned something from this discussion. Thank you all.

Hey man, youre from brazil too right? Nice.

 

[InTheShed]

A pour through test requires distilled water and an hour wait between fertigation and distilled:

Steps for the PourThru method
1. water containers to saturation (so that a few drops of water come out of the bottom of the container) with the normal irrigation water they have been receiving
2. after container has drained for one hour, place a saucer under the container
3. pour enough distilled (DI) water on the surface of the container to get 50 mL (1.5 fluid ounces) of leachate to come out of the bottom of the container (Table 1)
4. collect leachate for pH testing
5. calibrate pH meter
6. measure pH of samples

Source:

https://www.css.cornell.edu/courses/260/Media testing.pdf

A slurry test is much easier to perform (using dry substrate and distilled water).

 

[bruno12345]

A pour through test requires distilled water and an hour wait between fertigation and distilled:

Steps for the PourThru method
1. water containers to saturation (so that a few drops of water come out of the bottom of the container) with the normal irrigation water they have been receiving
2. after container has drained for one hour, place a saucer under the container
3. pour enough distilled (DI) water on the surface of the container to get 50 mL (1.5 fluid ounces) of leachate to come out of the bottom of the container (Table 1)
4. collect leachate for pH testing
5. calibrate pH meter
6. measure pH of samples

Source:

https://www.css.cornell.edu/courses/260/Media testing.pdf

A slurry test is much easier to perform (using dry substrate and distilled water).

Well, to me pourthrough is easier, and less disturbing to the roots, especially if you would analyse more deep soil than your surface soil. The basic principle is just watering you plants and waiting, just come after 1 hour, pour the right amount of liquid and its done hehe.

And also, you dont need distilled water to do it, as long as you give the plants only the required to produce 40-50ml of runoff.

If you give too much, you will "contaminate" your sample with the water you just gave. If you give the exact ammount, it will leachate only the water that was resting on the water bedding, and thus, giving a pretty solid number.

As im a peat+vermiculite grower, i also use pourthrough for nutrient monitoring.

 

[InTheShed]

By the time I have needed to test the pH of my mix, there are so many roots that digging down along the outside of the plant (about halfway down) and into the surface doesn't seem to faze them at all!

And if Cornell recommends distilled for pour through, I'd go with them.

 

[bruno12345]

And if Cornell recommends distilled for pour through, I'd go with them.

Well, Purdue university says that you dont need to use distilled water.
I ve made the experiment myself, you can try it too hahahahha

Just for visualizing.

Pourthrough procedure.
In figure A the nutrients on the pot that whe want to measure.

In figure B the correct pourthrough procedure. The correct ammount of water makes the water bed deslocates in the tray, but its only the blue part of it.

In figure C, if you use excess of water, you will have a contaminated leachate.

Font: Purdue university.


But hey, do what you think goes best and easier for you

 

[bruno12345]

And using fertilizer solution to make the pourthrough is specially advisable when using small pots or solo cups. As if you would use for example, 50ml of distilled water to produce it, you would totally dilute your nutrients in a small pot.

 

[InTheShed]

Thanks bruno! As a New Yorker, I'm picking upstate NY over Indiana.

And I have never found the need to pH test in anything smaller than 7 gallons, since the plants live there the longest.

 

[bruno12345]

Thanks bruno! As a New Yorker, I'm picking upstate NY over Indiana.

And I have never found the need to pH test in anything smaller than 7 gallons, since the plants live there the longest.

Oh im from Brazil so i cant properly choose one hahahahahhah

Oh sure, not the pH, but for those who would try the method i though i would give the full explanation, as this is a technique used for nutrient monitoring also.

Many hugs!

 

[FelipeBlu]

Hey man, youre from brazil too right?

No, I’m not that Felipe Blu - I wish I could play as well.
Obrigado!