This is my first grow and I’ve made a few mistakes thus far, but overall, things were going pretty well, but now, for some odd reason, no matter what pH I input into my soil grow medium, the run off will not drop below 7.1. I have 4 plants and 3 of them are run off 7.2. My plants are showing signs of being deficient of the secondary nutes. Does anyone have any idea why this is? In the medium is FFOF, some bio char, worm Gold plus, a little silica medium conditioner, and rice hulls/hydrocorn for drainage. I’m feeding the FOx Farm tio. I wanted to veg for 8 weeks and I’m in week 7. So I can’t switch them next week with this going on. Any incite would be greatly appreciated!


my experience with silica is that it raises pH dramatically. I would guess that its changing your pH in the soil every time you water.
Do the plants look like they are suffering? If not its probably ok.
Most soils in bags has calcium added which does the same thing but less dramatically as it disolves very slowly.


As I kept racking my brain, I figured that the only possible ingredient that might be the culprit, I was thinking about the silica, so that would make sense. My 2 white widow are suffering the most. Top leaves are yellow and thin versus the huge fan leaves they used to produce. I looked up the silica thing and it said that it has more of a neutral profile, but I did’nt have these issues until I potted up and that’s also when I added the silica. Well, i wanted to finish i 5 gal pots, but if the silica IS indeed the problem, I should probably put the girls in larger pots with more soil that doesn’t contain the silica at all. Do you think that may help?

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I would only be guessing about repotting.
Maybe someone else has dealt with this.
@Covertgrower may know someone else to tag with an answer.

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Well I appreciate you sharing your results with the silica at any rate. It’s honestly been driving me nuts lol

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Usually up-potting solves problems, doesn’t usually create them.

Can you explain this a little? Things that aren’t composted can cause issues too.
What kind of soil did you use?
How are you checking PH?

They are in Ocean Forest. I was reading that rice hulls were a suitable if not better than using perlite. I got the hydrocorn ideal from Jorge Cervantes. I have transplanted 3 times already using this same recipe and my run off has always been perfect 6.5, until I moved them into their final pots. At that time I added the biochar and a silica based soil conditioner. I have a good meter that i calibrate often, and I test the run off ph, ppm, and e.c

Can you post a picture of your plants?

Sure thing. The lights will come back on in about an hour and I’ll get some posted. Before you see them, let me mention that I did overfeed them 2 to 3 weeks ago, so they suffered some tip burn and such. I flushed them and transplanted about 10 days later after they recouped a bit. Thats when I noticed the ph rising. So what you will be seeing is deficiency “scars” and the lock out issues, which look super similar to a newb like myself lol. I don’t know if this info will help, but I just wanted to give you some context. Thanks again. I’ve put alot of work into these girls and I’d love to save them if at all possible.

All I know is I have found citric acid based PH down was to weak here to do the job and had to get a phosphoric based PH down to bring it down and keep it down.

That said the water here is bad at about a PH of eight.

I hope these are clear enough. Basically I’m seeing signs of deficiencies of all the secondary nutes. The top is yellow with small leaves, the middle looks good minus a few big fan leaves. And then the bottom has the smaller leaves yellowing. Also purple veins and the node spacing is getting long all of a sudden. They keep growing and eating I would assume as my PPM drop 3 to 400 every time I feed or water which is every 3 days. 1 of the Wedding cake has to be watered every 2 days or will droop too much.

have you tried epsona soil acidifier? i use it in my organic grow cuz after too dressing I sometimes get around 7.0pH. 2 tables spoons top dressed into the medium normally gets me down to 6.6pH. just an idea. or you could flush and reset.

I also recommend a flush and reset. With Properly PH’d water.

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I picked up a bag of a Promix soil from a local nursery this spring that was a coco coir and rice hull mix.
I used it for tomatoes peppers and basil. I was surprised at how it compacted and solidified in the containers. For seed starting it was fine, but I wouldn’t use it for long term growing. Rice hulls are attractive as an organic amendment as they will eventually breakdown in the soil but my feelings are that they just dont work as well as perlite.


Hummert soil, peat compost and rice hulls.
It is 11 bucks a bag. But I was not impressed.

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Hey much appreciated. I will look into it. From everything I can gather its easy to bring the pH up in a medium, but not so easy trying to go down and stay down without constantly adding something. I even read that the pH of a soil medium is what it is and not matter if you try and up the pH of let’s day your nutes, it will buffer that number to what the medium pH is. I kind of belive that, because, not knowing any better, I pH’d the nutes on 1 of the plants down to 5, and it STILL came out 7.2. And I water/feed VERY SLOWLY so it doesn’t run down the sides of the bag and throw off the true number. Im baffled at this point. Someone earlier said that every time they used silica it pushed the pH up. I didn’t use the liquid silica, but I used the Silica Soil conditioner which is 86% silica and the rest are trace minerals (zinc, calcium etc). Thats why, I figured maybe if I pot up 5 gal to a 10 gal, I may be able to set a good enough area of soil that IS correct for the roots to reach into. Thats just my best guess at this point. These girls are getting big though and I AM vertically challenged at just 6 ft, so I REALLY wanted to flip them in the next 10 days, but I just can’t if they aren’t healthy. I could monster crop them or super crop, but again this is my first grow and that’s probably something I won’t want to mess with right away I would assume. Sorry for the rant- got sto while typing and started rambling :rofl: Thanks again (tried to send last night but there’s obviously a limit to how many messages a newb can send out there first day lol)

I had no idea. I actually keep some around the house. I had planned on giving them compost tea today thats been brewing (Boogie Brew compost tea). Can I still add the Epsom salts?

Ok gotcha. Yes thats why I got them, for the potential of improving my soil over time. Thanks for sharing your experience. So far, my soil consistency has been great and the drainage has been on point as well, but who knows whats going on in there since the last replanting.
@Covertgrower I flushed them thoroughly when they were overfeeding a few weeks back. Is it ok to flush again? I just got my 10 gal bags today. They seem to be getting a little of their color back today after the last feeding. I pumped up the nute concentration a bit (as I had been underfeeding, using on 30 % of the recommended feeding schedule) and pHd that to 6 in most cases and 5.85 on one of the plants. I also read that compost tea can help acidify the medium, so I planned on giving them that today, and then replanting Saturday into some fresh FFOF, with just perlite and some Worm Gold Plus (which is worm castings, with kelp and rock dust)? Should I just skip the compost tea and go ahead and reset instead?

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I ran into some issues like this with an auto in soil but not using silica (yikes). Someone posted using soil acidifier. While I have a bag of this, it won’t work because it usually takes several months for the sulfer to bring the pH down. By then you’ll be dead in the water. What did help me was using spaghnum peat moss as its inherently acidic and should help bring your pH down in conjunction with a flush. Be warned, the peat seems hydrophobic to me - if you top dress water will just move around and take hella long to absorb into the medium, so you can either mix it into what u have or top dress which I don’t reccomend. But…if you do, just spray it with a water bottle first cuz that will help with the absorption rate. FYI a big bag of peat is like $12 or something at lowes.


Is there a reason to flush?