PH, Pests, LEDs & Leaves

Peace space travellers.

I previously wrote under “Diseases” heading and topic “Leaves have bruises and some turn yellow and brown”. And many replyed @dbrn32 @velcrothumb @donaldj. Thank you so much.

Following your expert advice, I’ve done some PH measurements. Took a bit of practice calibrating and now I think I have good measurments.

Medium - organic soil

Indoor LED - 1000w 12on/12off

Day 20-25C (68-78F)
Night 17-21C (64-70F)

Humidity 30%

No CO2

My 4 plants are flowering for about 11 weeks now. The tendrils are clear, yet when I cut a bud and let it dry a few days the smoke is fantastic. Now that we got that out of the way, I seem to be having some problems and I’m interested in your advice.

First is the Jack Herer plant. In my previous post we determined I overfed the thing (poisoned it?). One and a half weeks ago, I did a massive flush of it, that seemed to have helped some. I say ‘some’ because the plant is not as sprightly as it once was. Two days ago, the PH was 5.3 on this plant and yesterday I watered it and and applied some pelletized lime. Many of the leaves look like the one pictured below (back side is enlarged). Do you think the yellowing looks like a ph problem? or is it pests? both?!


The PH on my other plants (Amnesia Haze & J.H.) ranges from 5.1 to 5.7. I’ve applied some of the lime pellets to those as well. The tips of the leaves on these plants are a little brown, but the plants appear to be in good overall shape. How long would it take for the PH to get back to 6.0?

Environmental issue: My LEDs partially died about a week and a half ago, about one third of the leds went belly up. dead. I since replaced the fixture with a new one, but the plants went about 5 or 6 days without proper light. How detrimental is this sort of interrupted light during the flowering phase? I’m now on my 3rd LED fixture since August (this would be a story for a different post, eh?)

I probably have another week or two of flowering before harvesting (I guess). I will check ph again in a day or two. I’m not sure whether to apply more nutrients, or just water until harvest time.


Well there’s definitely an issue with the ph. The lime should help, are you watering a little higher than target ph as well?

Once you get that in line, will probably be easier to see where you’re at with everything else.


I just came back to see if you had posted. What are you using for soil? Most we target closer to 6.5 ph unless it’s some sort of soilless mixture. Did we already go through this on the other thread?


The water has ph 8.0. Higher than I thought it would be.

The soil is an organic potting soil mix. sphagnum peat moss, processed forest products, coir, perlite, organic fertilizer, and yucca.

I used all of the soil. I don’t have any unused soil to test.

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Ok. So you’re low to mid 5’s on ph and targeting 6.0 correct? And you’re watering with ph 8.0 water? Please don’t do that.

When did you add the lime?

Yes. I am targeting 6. What should I water it with??

Added lime yesterday.

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Never go out of range when watering. If you want to hit a higher target ph in the soil, use the highest NORMAL ph you would expect. In this case, no higher than 6.8.


what do i use as a water source? Prey, is there a virgin god of water?

If my soil ph is so low (5.3) and the water is 8.0, then the ph in the plants is way out of alignment.

Wouldn’t they offset? Why would it be necessary for me to add lime? I’m very confused.

The lime will act as a buffer for your soil.

As far as watering high, you would think but it doesn’t work like that. All you end up doing is shocking roots from one bad condition, to the extreme opposite bad condition. There’s not enough time for the soil and water to interact before it’s absorbed by the plant. If you’re a few tenths low and offset by watering a few tenths high, that’s perfectly reasonable. But when you start getting to a whole point or more off, it usually does more harm than good.


You can add a bit of vinegar to the water, then pH it, add a little more, etc. until you get it where you want it. It won’t take much if it is drinkable water. If it has added nutrients that will change the ph, so you add nutrients, test the pH, maybe add vinegar, etc. until you get it right.

Everything that goes on your plants should have the proper pH. And pH is log based, so pH 5 is way more acid than pH 6. If you add them 50:50 you don’t get pH 5.5.

I realized that my whole house water filter hasn’t been changed in a while. That’s probably why the PH is so high. (probably why our water tastes like cardboard lately) I will replace the filter that should bring the water ph closer to 6. The filters have charcoal in them.

I carbon filter can cause it to move a little, but how do you know it will be 6.0?

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If his water has a low tds to start, it won’t take much to effect a large change in ph IMO.

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I agree. I may just be a little confused from reading so many different threads. But sometimes I feel like we’re testing ph here, and other times we’re guessing.


Sorry for my delay has been a busy week for me I actually looked at plants in similar condition while out of town Tues and in about 2 minutes had found the issue for my uncle. He was ph adjusting water prior to adding nutrients being clones I gave him was quite easy to spot that they were not healthy
Your pictures show you are on the right track leaf damage points to Calcium which is almost always ph related


I don’t know if I know. I believe some of the minerals, when removed, make the PH more normal. I think I read that somewhere. I will certainly let you know. Meantime, my plants are thirsty!

Donaldj. Hi. I doubt these emails get encrypted. Do you know?

I’m almost 100% certain they do. What I’m wondering is if you’re guessing or actually testing the ph with an accurate method? Or guessing? Perhaps I’m not understanding your verbiage is all.

Hi Sorry about starting the new topic and abandoning the original one. I’m not 100% clear best way to use this forum.

I am using the apera ph tester as you recommended in the other thread. I calibrated the meter carefully, I’m not guessing. I watered yesterday with distilled water and am waiting for my water filters to arrive. The tendrils are starting to turn cloudy on the plants so I am probably within a few days of harvesting, maybe in a week.

MEANWHILE, I think I have a new problem. I am testing some buds (LOL) and when trimming one of them I see these small balls that are forming in the buds. Are these seeds??? Could this be the result of stressing the plants? I took a picture, not sure if it’s clear enough but you can make out these small round sacs under the bud. What do you think? Thanks for your help.

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Could be. Could be calyx from foxtail as well. Take them away from your other plants and peel one open to see.