pH lockout....ProMix ph low from bag

I've got a few plants going that have some leaves yellowing and crisping up. Also some spotting on some other leaves higher up.
Im running ProMix potting mix....and I ran it my last auto grow and had these same issues to a point where it basically killed my grow. But I chalked it up to my mistake...thought I'd over fed to a point of no return on autos (was my first try with autos).
But tonight I noticed it happening again with this new batch of photos.
They're still in solo cups right now so I ran some water through and had a runoff ph of 4.8 and ppm of 1300. I only starting feeding them last week....twice at 225ppm and 6.0 ph. So I knew it shouldn't be my fault this time.
So...I ran some higher ph water through over and over and could only get the ph up to 5.3 but ppm came down to 240.
Then I decided to do a slurry test on this Pro-Mix potting mix that I'm using. I used 1 part soil to 2 parts neutral h2o.
It ended up being 4.8ph and 650 ppm straight out of the bag.
I'm going to re-pot tomorrow and try get as much of this stuff off the roots. I'll probably use some of the Pro-Mix HP bale that I bought.
My question:
Could I use this again.... if I amended with Dolomite lime?
And...right now...if I watered in some lime....would it increase the pH? Since straight flushing isn't working very well.

Ok, just for starters you will have the best luck with peat based mixes at 6.5 - 6.8

I think you got a bad batch of promix. It shouldn't be lower than 5.8 out the bag. I had this happen with Sunshine 4, their peat moss supplier was switched and the pH went way up.

All I can say is get a different potting mix. I wouldn't use this stuff and try to amend it, more trouble than it's worth. If you can get your hands on a bale of berger bm6, thats good stuff and cheaper.

Over time I went from pro mix hp to sunshine to berger. I have learned to test every batch. I am going to move back to RDWC anyways but thats just me.

Renfro said:

Ok, just for starters you will have the best luck with peat based mixes at 6.5 - 6.8

I think you got a bad batch of promix. It shouldn't be lower than 5.8 out the bag. I had this happen with Sunshine 4, their peat moss supplier was switched and the pH went way up.

All I can say is get a different potting mix. I wouldn't use this stuff and try to amend it, more trouble than it's worth. If you can get your hands on a bale of berger bm6, thats good stuff and cheaper.

Over time I went from pro mix hp to sunshine to berger. I have learned to test every batch. I am going to move back to RDWC anyways but thats just me.

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Thanks for the reply. I'm using coco in hempy buckets right now with my other plants...and was considering doing them again with this batch of plants. But this issue is going to force me to transplant so I might just do the grow with the unopened Pro-Mix HP bale I have in the garage. I'll be sure to test it first tho.
Do you ever amend with lime when you're growing with peat? I did on my first ever run with SS#4 but haven't since.

tst2015 said:

Thanks for the reply.

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No problem.

tst2015 said:

Do you ever amend with lime when you're growing with peat?

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I never have personally but I would imagine the manufacturer does. I would just be guessing with the lime.

Renfro said:

No problem.

I never have personally but I would imagine the manufacturer does. I would just be guessing with the lime.

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Hey...just wondering your thoughts on this. I've rinsed some coco and its ph is about 5.9
I was going to transplant into this and was wondering....should I try to rinse this crappy ProMix out of the roots before I transplant? Maybe dunking it into some lukewarmish water and loosening everything up?
I've never transplanted for this reason before so not sure.
If I leave the crappy ph ProMix in with the roots...will the transplant still work get the ph up? Or would washing the roots shock the plants too much? I'm on the fence with zero experience lol

I have never had the balls to try washing the soil off the roots. Probably damage them a lot and shock them for sure.

Renfro said:

I have never had the balls to try washing the soil off the roots. Probably damage them a lot and shock them for sure.

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Ok I'll just plant transplant as normal. Thanks

Renfro said:

I have never had the balls to try washing the soil off the roots. Probably damage them a lot and shock them for sure.

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The first DWC I ever did I unpotted a plant and using lukewarm running water rinsed absolutely everything off and it took some doing. Dropped it into a netbasket (that was too small) and filled around it with decorative stones from an aquarium supply. The sucker never missed a beat. Never drooped. Stood still about 1 day and then it was off to the races.

I would imagine it has a lot to do with how rooted it is. I have never done it personally, perhaps your method will work well for @tst2015 Thanks for sharing your method.

hotrodharley said:

The first DWC I ever did I unpotted a plant and using lukewarm running water rinsed absolutely everything off and it took some doing. Dropped it into a netbasket (that was too small) and filled around it with decorative stones from an aquarium supply. The sucker never missed a beat. Never drooped. Stood still about 1 day and then it was off to the races.

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I just plan on putting them into coco. I did two last night (before I saw your post) and tried knocking as much dirt off as possible without disturbing the roots too much. But I didn't get a lot off. The roots are pretty healthy and quite a lot of them....but not root bound.
If I wash the dirt out...do you think I should use ph'd water thats close to the current ph (5.0) to avoid some shock or would going up to 5.8 be tolerable for them? Thanks

tst2015 said:

I just plan on putting them into coco. I did two last night (before I saw your post) and tried knocking as much dirt off as possible without disturbing the roots too much. But I didn't get a lot off. The roots are pretty healthy and quite a lot of them....but not root bound.
If I wash the dirt out...do you think I should use ph'd water thats close to the current ph (5.0) to avoid some shock or would going up to 5.8 be tolerable for them? Thanks

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In coco I’m not really sure. But 5 water is a bit too acidic for most feedings of cannabis. I also don’t know if you need to be concerned about it. In hydro all organic debris needs to be eliminated.

hotrodharley said:

In coco I’m not really sure. But 5 water is a bit too acidic for most feedings of cannabis. I also don’t know if you need to be concerned about it. In hydro all organic debris needs to be eliminated.

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My coco is flushed to about 5.9 when I tested it. But my solo cups in this Pro-Mix are still sitting at 5 after repeated flushing with higher ph water. Not sure why flushing isn't working to raise it up...but I gotta transplant them out anyways because theyre not wanting to dry out. Takes them about a week to start getting dry. With the amount of roots...I would think I'd be feeding every 2-3 days. And thanks to the moisture...I was dealing with fungus gnats.
This Pro-Mix really screwed me lol

tst2015 said:

My coco is flushed to about 5.9 when I tested it. But my solo cups in this Pro-Mix are still sitting at 5 after repeated flushing with higher ph water. Not sure why flushing isn't working to raise it up...but I gotta transplant them out anyways because theyre not wanting to dry out. Takes them about a week to start getting dry. With the amount of roots...I would think I'd be feeding every 2-3 days. And thanks to the moisture...I was dealing with fungus gnats.
This Pro-Mix really screwed me lol

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Pro Mix is peat. Peat has a starting pH of 4.5-5.0. This is why new unused peat should have feed pH at 6.0-6.5.

ProMix potting soil has the same time release organic nutes that's in their Veg & Herb blend and I had nothing but burning problems using either mixed 50:50 with the ProMix HP. Went back to HP alone and had no problems unless I overfed with hydro nutes.

I'm now using the HP with some added manures, worm castings and myco and feeding with Mega Crop. They're doing great.

OldMedUser said:

ProMix potting soil has the same time release organic nutes that's in their Veg & Herb blend and I had nothing but burning problems using either mixed 50:50 with the ProMix HP. Went back to HP alone and had no problems unless I overfed with hydro nutes.
.

I'm now using the HP with some added manures, worm castings and myco and feeding with Mega Crop. They're doing great.

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Yep...I'm done with this stuff. My first grow with it went ok but maybe I lucked out...or mixed in Dolomite before I potted. I can't remember. But I just got a new bale of the HP that I'll use next time I'm doing a soilless grow.
I really like coco but hate having to water so much...due to my crazy work schedule. Maybe one day I'll build a irrigation setup

I used MegaCrop on a couple of my grows. Awesome stuff and easy to use...not to mention... very cheap.

Just an update...
I transplanted two as normal into coco about 36 hours ago. They arent showing any shock. Still some new discoloration showing but hopefully that'll slow down and stop.
I transplanted the rest of them about 18 hours ago. I used some water in a bucket and washed the old soil off the best I could without pulling the root ball apart too much. Probably got about 80-90% of the old ProMix off. Then replanted in Coco and gave them a little nutrients. They are also looking good. No wilting or anything yet.

One question @OldMedUser when you're using MegaCrop. Are you cutting back when you hit flower? Ive noticed on there wasn't as much fade as I usually get when I harvest. I was only using about 3.5g til week 7....then I cut back and was still pretty green at chop.
Now, Ive got Hempy buckets going in my flower room right now and I feed every 2 days...so I'm only feeding at about 1.5g. I was thinking about bumping it up a bit but I'm seeing some dark green leaves at the top and a little bit of cupping (could be light related...can't get my lights any higher in tent). I'm also using Massive as PK booster and its 1-2-3 NPK so I thought I'd drop my MegaCrop to account for that.
I'm still trying to figure out ratios lol