Flushing for over-fertilization

I've a plant that I over-fertilized. It doesn't look terribly over-nuted; I've seen a lot worse. Well, I decided to flush a bit in order to wash out the excess. I had no intention of tossing three times the water as soil; I had planned on about three gallons of RO water, pH around 6.5. After the first gallon I tested a sample of the runoff. The pH was 5.9. So, I gave it a second and third gallon, yet, the pH remained steady at 5.9. The water was a bit yellow, so I kept on flushing with an additional two gallons of water, but the runoff held a stubborn 5.9. Common sense telling me that a lot of the excess had been washed out, and the fact that it was way past my bed time and I had lost patience, I gave up.

I've seen plants that were over-nuted before, and with a couple of gallons of water for a flush, and a few days later, the plants looked good again. I didn't measure runoff, but the plants regained their health. So, that is also why I gave up tossing water on it.

So, I realized that something was buffering the pH, and unless I tossed another seven gallons of water on the thing, the pH wasn't going to budge. Now, I don't know if what I measuring was an accurate representation of the overall soil pH. I'd say that after letting the plant drain, I recovered at least half a gallon of runoff after each flush. Each time, the amount of runoff was about the same. I wonder if it was too dilute, which would mean that the actual soil pH was even lower than the measured 5.9. If it wasn't dilute enough, then the actual soil pH was probably higher than 5.9. All I could think of was the dolomite lime in the soil was buffering the pH. But, isn't lime supposed to maintain pH at about 6.3-6.8? I wonder if the 5.9 is the real pH of the soil? I dumped five gallons of water on the plant, and each time the runoff was a stubborn 5.9. I'm going to wait a day or two and see how the plant responds before tossing more water on it again. It's hard to imagine that it was way over-fertilized, because I know how much fertilizer I gave it, and I've enough sense not to poison it too much. I might have overdone it a bit, but I certainly didn't toss way too much fertilizer on it.

What do you all think? When I finished, the water was still a bit yellow, but less so than when I started the flush. I don't like measuring runoff, because I don't seem to know how to.

Hey AY what is your soil made up of? Sound to me like it has a pine or some type evergreen is the soil mix.

FFOF soil with a tablespoon of dolomite lime per gallon. Later on, if the information I've given isn't enough, I'll fill you in on the details of my grow. All I know is something's buffering the pH. If in a couple of days the plant looks better, than I won't worry about it. The pot is four gallons. I should think that running five gallons of RO water through would it would help rinse it out a tad bit, don't you? Maybe I should have waited until I had four gallons of water, a gallon of water per gallon of soil, and then measured the pH of that instead?

Also, as I mentioned, the water, although much clearer after the flush, it was still yellowish in color. However, my goal isn't to wash every last nutrient out of the soil.

I'll check back later on tonight. Off to do some stuff and see some friends.

Okay, I flushed another plant. Again, it isn't that bad in appearance, but bad enough to deserve a flush. This one is in a five gallon pot. The first two gallons of water I just tossed on without adjusting the pH. For the next four gallons I tried various pH, ranging from 6.4 to 7.2. I flushed with a total of six gallons and the result was the same as for the last plant: the pH held steady at 5.8 for this one.

The plants don't look that bad, but the pH sure does seem to be off, and before I add anymore water, I need advice. Should I just let it be? Should I continue flushing until the runoff is where I want it. What is buffering the soil pH so well? I added one tablespoon of dolomite lime per gallon of soil when I first planted, but it is supposed to buffer at a higher pH. Something is buffering my soil, though, and at a low pH. What to do? I just can't believe that I over-did the nutes that much. I must have flushed out the excess with five gallons of RO water for one plant, and six gallons for the other, yet, the pH won't budge.

The plant I flushed yesterday seems to look better, at least not any worse than before the flush. Any ideas?

I'd put some dolomite lime in the soil...1 tbs sp per gallon of medium, but it may take a little while to buffer it....sorry to hear about your problems man.

I'm assuming you have been adjusting your feed solution before every feeding? If you haven't this could be dropping it. I know my FF nutes always sit around 5 something after mixing them up with RO water. But I know you are experienced enough to know this...so this is weird, I wonder if maybe your pH adjusters are drifting back down after awhile. Try adjusting a gallon of your mix and wait a few days and see if it is drifting back to those lower numbers??? I'm just brainstorming here...lol

Wouldn't that be a pisser! If the KOH 30% wasn't holding the pH. Ahhhh! but I remember having left a gallon of pH'd nutrient solution out over night, the next day the pH was still the same. So, hopefully that isn't the problem. I could do a test on purpose to see how long it maintains for three days or somethinglike that.

So, even though I didn't toss 12 gallons of water on the 4 gallon pot and didn't pour 15 gallons of water into the 5 gallon pot, you agree, the pH should at least change a bit?

Thus far, neither of the plants that I flushed look the worse for it, but I know the pH is low. I guess I could add a tablespoon of dolomite lime to a gallon or two of water and see what that does, but as it is the soil is saturated. What do you think?

PS. I've had the 30% KOH for several years, but I haven't changed it, because it always seems to work.

Okay, LF, I'm going to buy another bottle of pH UP. I spoke with the dude at the hydro store, and he agreed that it could go bad after a few years. Of course, he's going to say that, but I think you might be onto something. So, off to the store in a few minutes to buy another bottle. Thanks, and if you have any other ideas, let me know.

Oh, I have the chunky dolomite lime. I wonder how well it will dissolve in water? Plus, before I potted the plants I added a tablespoon of it per gallon of soil. Should I really add more?

I'd try the new adjuster first. I had a bottle that my best friends widow gave me when he passed away, and it would adjust the mix, but would drift right back within a 24 hr period...thats what made me wonder if yours was old.

I'd let them dry out before I watered them again...and maybe add a tbl sp of lime to the soil...just to be safe. But I'll bet thats what was happening. Mix yourself up a batch and see what it does in a couple of days...I'd bet that was the problem. But you would think that the dolomite lime would still be buffering it...I dunno man, I'm just takeing guesses to....lol.

Yeah, thanks, LF. I went to the hydro store and ended up getting some Big Bloom instead. First, I want to do a test batch of fertilizer and see for how long it maintains its pH.

The dude at the store told me just to wait, and that over time the pH would go back up again. I really don't want to add more water at this time.

If you were to add dolomite lime to the soil, how would you do it? Would you sprinkle it on top and water it in?

ozzydiodude said:

Hey AY what is your soil made up of? Sound to me like it has a pine or some type evergreen is the soil mix.

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Hey, Ozzy, talk to me--why do you say it may have pine or evergreen in it? Does that drop pH? I ask because my grow shop guy says FFOF is now being made on the East coast with pine bark rather that redwood mulch.

legalize_freedom said:

I'd put some dolomite lime in the soil...1 tbs sp per gallon of medium, but it may take a little while to buffer it....sorry to hear about your problems man.

I'm assuming you have been adjusting your feed solution before every feeding? If you haven't this could be dropping it. I know my FF nutes always sit around 5 something after mixing them up with RO water. But I know you are experienced enough to know this...so this is weird, I wonder if maybe your pH adjusters are drifting back down after awhile. Try adjusting a gallon of your mix and wait a few days and see if it is drifting back to those lower numbers??? I'm just brainstorming here...lol

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Wonder if this has to do with the RO you begin with? My RO comes in at around 6.3-6.4, and after adding my FF nutes I am still right on top of that number. I'm baffled.

Alistair, this is probably horrid advice, but I've gotten to where I don't worry so much about run-off pH unless I'm having problems.

All the buffers and adjusters in all this crap nowdays seem to make it jump around all over the place, and I get like you: totally frustrated.

al....
FFOF contains a buffer, + you've added a buffer..... :confused2: lime takes awhile to react, you probably wouldn't see any immediate difference in ph if you did add it now. AND you might 'o.d.' them on calcium ..(too much ca can locks out other micronutrients) "buffers" work to maintain neutrality (7.0)
I don't have the answer.. but it certainly "appears" to be plenty rich in 'buffers'.. that said, I tend to agree with pencilhead.. "I" seldom test my runoff unless I experience a problem. I guess I've come to trust the mix(maybe too much! )

Well, I think it simply happened because I over-did the nutes, and as we all know, this can make the soil acidic. Now, as for what LF was saying, he very well could be right. So, tonight I mixed a typical solution of FF Tiger Bloom, Big and Open Sesame, pH 6.4. I will test it every couple of days or so for a wekk, and see what happens.

The funny thing is, the Master Chronics are the ones that are exhibiting signs of over-nuting; the White castle don't seem disturbed in the least. I guess the MC is nute sensitive. Three out of four of them are showing signs. I flushed two, and if the third one doesn't get any worse, then I'll patiently water it plain water for the next few weeks or so, and let the problem take care of itself. I'm not big on pouring copious amounts of water on my plants.

I think it was a good idea, though; because the two plants seem to have taken well to it, and the problem has seemed to have stopped. Some of the worse leaves look bad still;whereas, a lot of the younger leaves have made what seems like a full recovery. I just can't wait for it dry out. I'd hate to get root rot. That's another reason why I don't like the idea of flushing; I'm cautious against root rot.

After all this, I'll be need to chuck a plant anyway. It seems as though all eight plants are female. I'm just double checking one of the MCs to make sure it's female. If so, the worse, unhealthiest plant is chucked, problem solved. I need to thin out the crowd.

I think LF gave great advice. We'll see. The man at the shop was talking out of both sides of his mouth concerning whether I needed to buy fresh pH up or not. Then I grabbed a bottle of Big Bloom, and all of a sudden he wasn't quite sure that I really needed to buy fresh pH up not. Afterward, he proceeded to show me a fan saying, "I' not trying to sell you anything, but.."

Hick, after a good flush I was thinking that I had rinsed a good deal of the lime away. But, I guess I could hold off for a bit and wait and see. I think that after it dries out, and they get watered/fed with properly pH'd solution, and not to much fertilizer, the pH will go back up again.

Thanks,

Ali

LF, I put together a gallon of RO water with 2 teaspoons Tiger Bloom, 1 tablespoon Big Bloom, and 1/4 teaspoon Open Sesame, pH 6.5. That was 24 hours ago, and the pH is holding steady at 6.5. I will continue this test for up to a week, and see what happens.

Hello Alistair

Alistair Young said:

I have the chunky dolomite lime.

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I think this is your problem Alistair, powdered dolomite works much better than chunky when trying to keep the soil PH'd correctly.

eace:

HippyInEngland said:

Hello Alistair



I think this is your problem Alistair, powdered dolomite works much better than chunky when trying to keep the soil PH'd correctly.

eace:

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..certainly powdered would be 'faster' acting
Al... here's a pdf file that might help you

The amount of lime needed to achieve a certain pH depends on (1) the pH of the soil and (2) the buffering capacity of the soil. The buffering capacity is related to the cation exchange capacity (CEC). The higher the CEC, the more exchangeable acidity (hydrogen and aluminum) is held by the soil colloids. As with CEC, buffering capacity increases with the amounts of clay and organic matter in the soil. Soils with a high buffering capacity require larger amounts of lime to increase the pH than soils with a lower buffering capacity.

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hxxp://hubcap.clemson.edu/~blpprt/acidity2_review.html

View attachment LIME.pdf

Interesting read.

hXXp://www.lime.org/faqs.html

eace:

HippyInEngland said:

Hello Alistair



I think this is your problem Alistair, powdered dolomite works much better than chunky when trying to keep the soil PH'd correctly.

eace:

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:yeahthat:

And since I DO have pine bark nuggets in my mix, I use about 2 tbs/gallon, perhaps a little more.

DD

I thought all lime takes a while to break down to be effective (like weeks and even months), unless you use the "fast acting granulated" or whatever they call it.

Regardless- mad props to you Alistair for the very detailed info you shared here. Well documented and a clear and concise plan. Thank you very much! I learned something new today!