Soil runoff @ pH 5.0!? How did this happen so fast?

[lampost]

Doubtful your ph numbers are accurate. FFOF is properly buffered near 6.5 to 7.0 ph, I believe. That's where it should stay for a couple of months till the buffers fade.

What are you using to check runoff ph? If it's a color-coded result, (freshwater aquarium ph test kit, ph test strips...) the tinting of the runoff will skew results.

If using a ph pen, it likely needs calibrating.

Or, you are re-using soil.

Or, they forgot the buffers in that one bag of mix.

I guarantee that pH is correct. I have an Oakton pH pen that I calibrated before and checked after. It was dead on! I also confirmed with a ph test strip. The ph numbers are accurate unfortunately! I did notice the nitrates were off the charts! Total hardness looked about 400 ppm.

I thought the same thing... They forgot the buffers in this bag! Who knows. I've heard others say they had low ph (5.0) runoff from FFOF too, with little problems. I think FFOF is over-rated! I'll use something else next time. I even added my own buffers (albeit a very small dose, 5-6 tablespoons per bag of FFOF.

The fact that redtails was unable to save a ph-skewed plant scares me. Is it too late to sprinkle some dolomite lime on the surface and hope it will infiltrate the soil?

[lampost]

Well pay that extra attention more visually than actual doing stuff. You are going to give yourself an ulcer dude. LOL You are too funny

Yeah, I'm taking this shit pretty seriously. I'm unemployed right now so I've got nothing better to do. Also, I put a lot of money into this, probably $1500-2000 when all is said and done. This is my first crack at this too, so yeah, I need to make sure things are going right.

[Rusty Trichome]

Do you rinse the ph probe between use? Nutrient build-up can occur there, too.

The fact that redtails was unable to save a ph-skewed plant scares me. Is it too late to sprinkle some dolomite lime on the surface and hope it will infiltrate the soil?

Fresh soil, and a transplant. If you're going to lose them anyway...
I've transplanted ladies in late flower to save 'em, but you could very well pay a price. If not careful you can break branches or roots, they can go hermie and might not finish completely before you have to harvest them. (fully formed nanners) If no stress, and all goes well...slow/stunted growth likely till harvest. Might even stretch a tad if there's enough nitrogen in the fresh potting soil, but buds will likely be underformed.

If getting desperate, and you know for a fact you are losing the soil buffers, (ph swings, nutrient lock-out) I might be tempted to grab a gallon of water, and add a cup of lime and disolve as much as possible. Add it to the pot slowly. Flush it through with another properly ph'd gallon of water, so it's not all sitting on the top layer...and keep your fingers crossed.

[lampost]

^thanks!

I doubt FF forgot the buffers so I'm hoping it was just kind of a hot bag. Hopefully, the plants will show recovery soon. In my research it seems like a lot of people get pretty low runoff from FFOF. A lot of people are also saying runoff pH is a terrible indicator of soil pH! So, I'm gonna take it slow and hope that the plant starts looking healthier. I think the symptoms were from nute-burn. I'd given them the same dose as my larger plants and I don't think they were ready.

Anyway, nothing to do now but wait. I'll keep you all posted as to what happens with them. Shit, I should get a grow log going soon so I don't have all these scattered questions everywhere.

[lampost]

OK after all of my research I think this simple over-fertilization. Here is some info taken from a sticky post on rollitup forum:

"1. Over-fertilizing - the most common cause of leaf cupping aka leaf margin rolling, leaf margin burn, and leaf tip curl/burn is the overzealous use of too much plant food in relationship to factors such as plant size, vigor and rate of growth. The first unit of a plant to show moisture stress is the leaf at its margins and/or tips, reflected by margin rolling (cupping) or burning. Sometimes copper colored necrotic spots show in the leaf also. A hard, crispy feel to the leaf frequently occurs as well, as opposed to a soft and cool feel of a happy leaf. When you have a high concentration of salts in solution (or in the root medium) compared to lower salinity levels found in the plantâ??s tissue, water is actually drawn out of the plant across the root gradient in order to fix the ppm imbalance. IOW, this is a natural, osmotic response that serves to equalize salinity levels on both sides of the rootâ??s epidermal gradient. Back off on the amount and/or frequency of plant food. Too much plant food can also burn the roots, especially the sensitive root tips and hairs, which then creates another set of problems such as nutrient deficiencies. A note for the bio folks - as soil dries, the concentration of the remaining salts rises further exacerbating the problem. Leach (flush) your pots once in a while to get rid of excess salts."

I'm pretty sure this is it. The low pH (5.0) runoff is probably not causing any problems. I'm convinced that runoff isn't a great indicator of actual soil pH. All the symptoms are probably attributable to the over-fertilization with organic nutes (Humboldt Grow & Bloom Natural). Unfortunately, they may get worse as the soil dries out over the next several days. Although I gave it a semi-flush and this may've helped.

[Rusty Trichome]

The low pH (5.0) runoff is probably not causing any problems. I'm convinced that runoff isn't a great indicator of actual soil pH.

Runoff ph indicates the interraction between soil ph and water ph, and yes...it is an invaluable indicator. Nutrient uptake is limited on the outside edges of our ph. Lockouts will occur.

Are you adjusting the water before adding the nutrients? Every nutrient I've ever worked with is acidic (FF included) to some extent, and will lower your ph.

[lampost]

Runoff ph indicates the interraction between soil ph and water ph, and yes...it is an invaluable indicator. Nutrient uptake is limited on the outside edges of our ph. Lockouts will occur.

Are you adjusting the water before adding the nutrients? Every nutrient I've ever worked with is acidic (FF included) to some extent, and will lower your ph.

Well, the plants that had the problem have only had nutrients once. And I mix the nutrients and then later adjust the pH, however, I probably won't even adjust pH anymore. Tap water is at about 7.8 and after nutes it can come down to 7.1 or so. Just a 1/4 tsp of pH down per 5gal will get it at 6.9-7.0. I'm watering on the high-end of the range or neutral...

What I meant was Humboldt Nutrients doesn't lower it that much... not as much as I expected. It can lower about 0.2 - 0.7 pH so far from what I've seen depending on the nute combo used and the concentration at which it's mixed.

I agree that runoff pH is helpful.. but I think the pH is probably different at any given location in the pot... so even though it may be at 5.0 when it comes out of the pot... all hope may not be lost

[lampost]

Well, plants are doing OK. It's about 6-7 days after flush. I watered with pH 6.9 water and runoff was 6.0!!! Wooohooo!!

I'm CERTAIN that my pH readings have been correct. Last week when I first got the pH 5.0 on the Headband I measured the runoff on the healthier plants and they were all like 6.0 - 6.5.

The problem was too much nutrients too soon. When flushing I used a test strip to determine the nitrate of the runoff and it was like 300-400 pm (extrapolated since it was out of color range of test strips). Now it came down to about 20 ppm.... that is a HUGE difference!!

I've heard the curled up leaves edges may not recover! That's kinda weird, makes it hard to see how much they've recovered. But I think things are back on track now for the Headband!

[Ocotillo]

Runoff ph indicates the interraction between soil ph and water ph, and yes...it is an invaluable indicator. Nutrient uptake is limited on the outside edges of our ph. Lockouts will occur.

What Rusty is trying to say is shown in this handy PH nute uptake chart from the charts and graphs section of the problems section of the growing section. Glad you're back on track.

[lampost]

^Thanks.. I'm familiar with that chart.

I'm still not convinced that runoff pH is consistently a reliable indicator. I don't think the pH of my soil swung 1 point in the last 6-7 days, whereas the runoff did. Nonetheless, I do think it's a good "tool" and I'll continue to check it.