Help! Acidic soil causing a nute lockout even after a massive flush.

[Eschyz]

Hello everyone!

I'm currently in the middle of my first grow, and oh boy is it a ride. I made multiple mistakes, but was seemingly able to get everything under control. Most of those problems arised because of bad gestion of my pH level, which resulted in an acidic soil. My runoff currently read around 5.5/5.8 (I use two different kind of strips. One goes from 3.0 to 5.5, the other from 5.5 to 8)

Sadly, last thursday one of my plant suddenly catastrophicaly turned yellow on almost half of it's leaves mostly the lower ones. The yellowing is still advancing, albeit rather slowly, on others leaves. Just before that I had what I identified as a cal deficiency, beause rusty spot started to appear. I tried to flush my medium, but even after dumping 20 gallons of plain water in my 5 gallons bucket nothing changed runoff wise. Still at 5.5 and both of my strips give me the same results. I did this 2 times in a 2 weeks notice. Right now a lot of my leaves are dying, some are yellowing and others seems fine, the buds also lok fine, as they are even getting fatter (I'm chronologically 8 weeks tin flowering, but I stunned the growth and it's probably more around 4 weeks development wise).

I did not use any nutrient except a 4-4-4 gaia green powder fertilizer that I mixed with the soil. Since the 24 september I've started to use the grow, micro and bloom serie from General Hydroponic. I don't use cal-mag since I've read everywhere that my tap water should have enough in it, and since my soil is so acidic I figured it was a lockout.

My questions now. First, was I correct in my diagnosis of calcium and nitrogen deficiency. Second, is it normal to not have noticed any difference in my soil pH after flushing with 4 times my soil volume in plain water. Third, what the hell am I doing now, how can I get that soil pH under control ?

I don't remember the soil I'm using because this was my friend setup that was transfered to my place because of a lack of space in his new place. We use a 1000 kingled, from a quick search online the true wattage is 185W. As I said I use the GH basic serie and I used the schedule provided by this website. We are growing an Ak-47 autoflower.

Some picture to help you guys helping me out.

Ps : English ain't my first langage bla bla

Edit : I have checked for bugs. I have few fungus gnats, but I highly doubt they are the problems. I water maybe once every week(when the top inch is dry) and I don't see that many even when I'm looking for them.

[Tersky]

What is the ph of the water going in? Ph your water higher to get a higher runoff.

[az2000]

That may work for the OP. But, I just want to say that ph up typically contains salts. It's basically a fertilizer. It doesen't have a NPK label on the bottle because it's not sold as a fertilizer. They aren't required to list it as such. So, what tends to happen: people overfeed, which acidifies the soil. They add more ph-up, which adds even more salts to the nutrient solution, causing stronger nutrients, more buildup, etc. (It happened to me when I was new. It's like a spiral. I was pouring hydrated lime into my soil to reduce ph -- when the whole time I was overfeeding. It's funny to think back on that. Monitoring runoff ppms is what helped me untangle all that. The soil ph probe, Accurate 8 Control Wizard, also was key. I saw the soil ph drop as the runoff ppms rose. It was like clockwork. Lockout occured at 2500ppm, and the soil ph was around 4.0. As long as I reduced the nutrient strength when it was in the 1800-2000 ppm range, and didn't let it go higher, I never had a problem. I was even able to stop ph'ing my nutrient solution. It was all related to each other.).

Note: Not all ph-up/down products are synthetic nutrients. Some are organic and don't add salts. But, since the OP is using hydro nutrients in soil, I assume they're also using the typical ph-up product (potassium nitrate, or something like that. I forget.).

Since he's already flushed, I think he should just wait and see. Runoff ppms might reveal something. (I should say that my runoff ppms mentioned above could be specific to my soil and nutrients. I think it's the kind of thing a person has to develop a *trend* with their own grow. I don't think it's a universal number that applies to all grows. It's best to watch it for awhile. But, it may be insightful to know what it is right now. After all that flushing, if it's in the 800-1200 range, I'd probably ride it out, hope for the best.

The problem with chasing ph in soil is that the OP (or at least this is what I did) will water sooner, trying to correct the ph. Holding the soil too wet will keep the ph low. I would step back at this point. But, I could be wrong!

[Tersky]

Yeah I forgot he said soil and was thinking coco. I am still learning the soil side lol. Yeah i agree with you completely. I think i skipped the part where he said he added fert to the soil. that changes things. Good catch. Maybe i shouldnt comment right after a bong hit lol.

[Eschyz]

Damn, I almost didn't see that comment. I am definitly using a synthethic ph up, potassium hydroxide to be exact. The thing is, when I saw the first sign of a nutes problems I started to pH my water and it kinda resolved everything for a while, so I didn't think anymore of it. I'll try to slack away from it or maybe find an organic solution. I can't thank you enough for those advice!

[az2000]

Sadly, last thursday one of my plant suddenly catastrophicaly turned yellow on almost half of it's leaves mostly the lower ones.

Since the 24 september I've started to use the grow, micro and bloom serie from General Hydroponic.

I don't use cal-mag since I've read everywhere that my tap water should have enough in it, and since my soil is so acidic I figured it was a lockout.

My questions now. First, was I correct in my diagnosis of calcium and nitrogen deficiency. Second, is it normal to not have noticed any difference in my soil pH after flushing with

GH Flora 3-part is for hydroponics. It may work in soil, but you're basically bypassing the microbes and treating the soil as a medium. It just seems a stark contrast to Gaia Green (which is intended to work with the roots/microbes to make nutrients available as the plant needs them). Not saying GH 3-part won't work, or is the problem. But, this happened a week after you switched to hydro nutrients. Some "tea" r fish emulsion, or guano, etc. might have been a better choice for soil (especially when you started with juicy stuff in the soil like that.).

Which soil are you using? Does it have a brand name? They look overfed to me. IMO, acidity typically comes from overfeeding & salt buildup.

I think soil ph is overrated because the soil ph rises a point as it dries. All you see is the wet ph. And, measuring runoff ph, you're only seeing how the liquid was affected by the soil as it passed through. In other words, if you water in one sitting, it won't spend much time in the soil to acclimate to the soil's ph. If you pour a high volume, you're diluting the sample too.

If you google for "NCSU Pour-through extraction method," you'll find a PDF describing a university ag department's method for measuring runoff. When you think about how tedious that process is, you get an idea why just random runoff is dubious (as an indicator).

Some growers suggest a slurry test. But, that just samples a small part of the soil. I use a relatively expensive soil ph probe. I see different pockets of ph. (Like I said, I see the ph change between waterings, from wet to dry. It's not a static thing like a hydroponic reservoir. I'm not saying you can't fine tune it. But, I think most people chase it more than is warranted. I haven't ph'ed a nutrient solution in 5 years. I just pour it in and never have any ph problems I can identify. Unless I overfeed.).

How much GH 3-part did you mix? How much of each bottle (per gallon or liter?). I can tell you how strong that was. Typically you want to use half the label strength. But, since your soil was amended with organic nutrients, you might not need to suppelement them much. The problem with GH 3-part is that it's immediately available. If the soil just needed a touch up, suddenly they're getting a direct supply of synthetic nutrients. Perhaps at a strength that is for *hydro* (which has no background nutrients in the water). I bet something like this happened. You overfed for a week.

[Eschyz]

I really can't tell you which soil I used. My friend bought it and I just didn't really paid attention. It could be the Foxfarm Ocean Forest, but I'm only basing this on the color palete of the bag,

The first problem to arise was a burning that started from the tips and the edgse, and every documentation I found pointed to a lockout and the runoff pH I read was also concluant with this. The reason I switched to the Gh 3-part was because since I was going to flush my medium, I wanted some nutrient to feed my plant, as of the guide on grow weed easy. I also read that those could be use in soil there. I mixed 1/2 tsp of Micro and 3/4 of bloom in a gallon of water for this particular plant.

The flush I did 3 days ago was plain water only, no nutes and the plant is still slowly dying off.

[az2000]

2.5ml/gal Micro & 3.75ml/gal Bloom isn't very strong. (I was expecting you to say 10 and 15ml). What you mixed is about 200ppm. It creates an NPK ratio 1-1.45-1.36. That's not bad.

If it were me, I would stop, let the soil dry/recover. If you chase this too much, you'll never know what's working. To some extent, plants will fall apart later in flower. You may have accelerated that some how (cutting N too soon.).

If you started with Ocean Forest amended with Gaia Green... that would be some strong oil. OF is reported to be significantly strong by itself. (It's not labeled, but government regulatory sites show: 0.30-0.45-0.05). That's pretty strong. By comparison, I mix my own soil and use a product that is 0.30-0.10-0.10. But, I only use that for 22% of the volume of the soil I make. The rest is soilless. I feed about 200-250ppm each feeding. (So, if you fed 200 on top of 100% OF, *and* had Gaia Green added into it, that could still be too much. Especially when the 200ppm are entirely synthetic nutrients, available for uptake. Not like a tea or something.).

Maybe your friend could confirm the soil?

If it were me, I would stop. Let the soil/plant recover after flushing. If you chase it too much, you won't know what helped. You may cause more problems keeping it too wet (because you're eager to help, and do something else to help it. I've done that.).

Everything sounds like overfeeding. The burnt edges/tips. You can have burn without salt buildup. Nutrient lockout is different than nutrient burn. Burn will cause the burnt tips and things. Lockout will often accompany burn. But, it ends up looking like deficiencies (the Ca def spots, etc. Yellowing.). You could have both.

Salt buildup will cause ph to drop. But, as I said, the soil ph will rise as it dries. Assuming the flush got rid of the buildup, the plant will consume more of the remaining salts as the ph rises (and is in a better range). The next time you water, the runoff ph should reflect this. It takes a little time for things to swing back the other way.

Something you can do is aerate the soil. Get a 1/4" diameter aluminum rod. Put one end in a drill bit, spin the other end against a steel file to put a rounded/pointed tip on it. Bend the opposite end 90 degrees to make a handle. Gently poke that into the soil, all the way to the bottom. That can help the soil dry faster, which will get the ph up higher (faster) so the plant has more access to the nutrients. It can help things swing back faster. Don't go crazy perforating your soil. In a 3-gal container I would do 4-6 plunges.

[Eschyz]

az2000 I've confirm that the soil we are using is Foxfam Ocean Forest. I'll try your rod trick right now and try to do nothing for the next few days, It doesn't sit well with my anxious personality, but I'll manage haha.

Thanks a lot!

[az2000]

Maybe someone else has some better ideas. But, after flushing with 20 gallons... I think I'd leave it alone for awhile and see what happens. If anything, I think there will be a risk that the plant will be hungry after all that flushing. I'd suggest that you look into "teas." Things that will recharge the soil. I think people bubble guano and worm castings in water or a day or two, and pour that into the soil. If you think it needs N, Pennington Fish Fertilizer (5-1-1) is good, and relatively gentle.

You said the runoff ph was 5.5-5.8. I don't think that's bad. As I said before, the ph rises as the soil dries. Maybe you've been keeping it too wet, killing it with kindness (eager to try something else). That can exacerbate overfeeding/salt buildup.

Now that you've flushed so much, I'd make sure it dries well. Do another wet dry cycle. In the future, if you think there is salt buildup occurring, you can pour enough water (each time) for 20% runoff. Instead of one big flush, you can do mini flushes each time. But, with organic nutrients amended into the soil, I don't think you should have to do even that.