High ph runoff

Hi all. I’m on day 45 lsd25 auto. ive been using advanced nutrients ph perfect micro grow bloom using ro water in soil. First grow..I chose these nutes because I thought I didn’t need to check ph etc… turns out the nutes are more suited to hydro.. so.. 2 weeks ago started seeing rust spots and some ends of leaves twisting. Stopped nutes, flushed and fed only ro water ph at 6.0 run off stays 7.2-7.4.. yesterday I added 2ml/l Florakleen, today I watered and checked ph run off still high 7.2 -7.4.. I flushed again 6.0 ro ( run off still high) then after flush I added 1litre per plant mixed with Florakleen 2.5ml/l. I’m out of ideas.. no idea what to do next? Keep flushing? Add nutes? mars hydro tsw2000 led at 65% 19-20inches above canopy. 18/6, 26c day temp 21c night temp , 50 rh, Also, day 45 should autos be flowering by now? anybody experienced this before? What can I do? Any advice would be hugely appreciated

Me mates in the same boat but in different medium. Using canna Coco professional and canna Coco a+b. Putting in 700ppm at 6.2 and the runoff coming out at 750ppm and 7.4-7.6 immediately. It's strange.

It's healthy, so he's just worrying about what he puts in. Have you done a slurry test to check ph? Runoff isn't too reliable in potting mix.

VincenzioVonHook said:

Me mates in the same boat but in different medium. Using canna Coco professional and canna Coco a+b. Putting in 700ppm at 6.2 and the runoff coming out at 750ppm and 7.4-7.6 immediately. It's strange.

It's healthy, so he's just worrying about what he puts in. Have you done a slurry test to check ph? Runoff isn't too reliable in potting mix.

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No..not even sure what a slurry test is, is that the soil test? 1st timer..learning on the job.. is your friend still feeding?

goldenbags said:

No..not even sure what a slurry test is, is that the soil test? 1st timer..learning on the job.. is your friend still feeding?

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The slurry test is the more reliable method of testing mediums pH. Runoff is unreliable in potting mixes as it will wash out the buffering compounds (usually carbonate) in the mix as you go which will swing pH, and RO having less buffering compounds will swing faster than tap water, so any buffers in the medium will effect the feed in a more violent mannerbas it runs through.

Soil usually has its own buffers from the mineral content which can provide unreliable runoff readings.

I wouldn't keep flushing and adding anything tbh, as that's usually where you'll start to run Into issues. I wouldn't chase runoff in potting mix to begin with, and would rely on a decent slurry test over runoff.

Mate is still feeding as he's in Coco and feeding twice a day. The runoff is coming out as he puts it through EC wise, but the pH is rising rapidly as it runs off. It's healthy so we are just worrying about what goes in rather than out. Just keeping it at 700ppm/6.2 for as issues ways start when to try and correct something that's not there.

If you do have high pH at the medium/root level, elemental sulfur will counteract the alkine components and lower the pH.

There seems to be a magnesium issue coming along as well. The high pH could indicate a build up of calcium carbonate which will effect Mg uptake and explain the alkaline pH.

Classic interveinal chlorosis

I'd hit it with a foliar of Epsom salt mixed with water and a wetting agent. Somewhere between 1-1.5 teaspoons per L of water with a drop of dawn soap as a surfactant.

If.your medium pH is very alkaline I suggest a top dress of elemental sulfur.

VincenzioVonHook said:

There seems to be a magnesium issue coming along as well. The high pH could indicate a build up of calcium carbonate which will effect Mg uptake and explain the alkaline pH.
View attachment 5209988
Classic interveinal chlorosis

I'd hit it with a foliar of Epsom salt mixed with water and a wetting agent. Somewhere between 1-1.5 teaspoons per L of water with a drop of dawn soap as a surfactant.

If.your medium pH is very alkaline I suggest a top dress of elemental sulfur.

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Excellent! Thanks mate, really appreciate u taking the time to help!!

Sadly this is seen all too often with new growers. Many new cannabis growers have no idea how or why plants grow at all (any plant, not just cannabis). They read a little bit, watch some YouTube videos and go out and purchase all kinds of nutes and start applying without a basic fundamental understanding of how plants grow and their needs. Hang-in there, do some homework and let us know what happens. Good luck, I hope you get it straightened out. Keep it simple and stick with the basics.

Cynister said:

Sadly this is seen all too often with new growers. Many new cannabis growers have no idea how or why plants grow at all (any plant, not just cannabis). They read a little bit, watch some YouTube videos and go out and purchase all kinds of nutes and start applying without a basic fundamental understanding of how plants grow and their needs. Hang-in there, do some homework and let us know what happens. Good luck, I hope you get it straightened out. Keep it simple and stick with the basics.

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I did that well and proper with my first plant indoors. Went full canna terra line with zym, rhizo, boost and pk.

Let's just say that the pH was a little low by week 6 as I had chosen a highly pre-fertilized organic mix to begin with.

Funny though, as I grew 6-7 foot photos outdoors for three years with nothing bar a decent garden with ewc, barley and kelp top dress every six weeks under mulch.

Switched to indoors and had this bizarre idea that I had to complicate everything because it was in a tent. Add to the insane $200 stack of nutes, I threw a mars TS like 12" from the canopy as that's what the manual said for fkowering, but I was running autos at 20hrs instead of the 12 in the manual.

So, all in all, my first plant was fried from light due to not understanding DLI differences between a 12 and 20hr schedule, and fried from a $200 stack of nutes that no-one told me to buy bar hype in my head. There is never too much time spent researching, as my lack of bit me in the ass.

My previous years outdoors should have made me the wiser, but I still feel for the hype due to being an avid hobbyist and ovlbsessing with everything.

Ahhhhhh, thanks for sharing. I understand completely as I was an outdoor grower for a long time. I got tired of the pests and took it indoors. Outside it was plants in a garden and no big deal; I could tend them and walk away without another thought. Inside, it's micromanagement down to the smallest detail. They keep calling me, lol. I'm surely wiser from it all, but sometimes it just doesn't sink-in and it's like I'm a noob all over again. Then I realize what I know and I'm like, DUH!

VincenzioVonHook said:

There seems to be a magnesium issue coming along as well. The high pH could indicate a build up of calcium carbonate which will effect Mg uptake and explain the alkaline pH.
View attachment 5209988
Classic interveinal chlorosis

I'd hit it with a foliar of Epsom salt mixed with water and a wetting agent. Somewhere between 1-1.5 teaspoons per L of water with a drop of dawn soap as a surfactant.

If.your medium pH is very alkaline I suggest a top dress of elemental sulfur.

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Hey do you think I could use RO water to do the slurry? Or it must be distilled?

goldenbags said:

Hey do you think I could use RO water to do the slurry? Or it must be distilled?

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RO is fine

Drop That Sound said:

RO is fine

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Hi..do i need to ph the water before adding it to the slurry?

VincenzioVonHook said:

Me mates in the same boat but in different medium. Using canna Coco professional and canna Coco a+b. Putting in 700ppm at 6.2 and the runoff coming out at 750ppm and 7.4-7.6 immediately. It's strange.

It's healthy, so he's just worrying about what he puts in. Have you done a slurry test to check ph? Runoff isn't too reliable in potting mix.

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I just had a look at the ingredients of the "420 Super Premium Planting Soil " that I bought online, I'm in Bangkok Thailand. I didn't bother translating when I bought it. I had no idea..super premium planting soil sounded good to me...weed had just been legalized! I just translated the ingredients and
>>>Main Ingredients<<<
•• All fermented crab claw leaves, finely sifted.
•• Pete Moss Classman
•• Fermented coconut flakes without tannins
•• Perlight
•• Vermiculite
•• Volcanic rock (Sri Lava)
•• Real earthworm manure
•• old bat droppings
Compost + Compost PT Garden formula
•• Rebone (substitute for bone meal)
•• Trichoderma
Chitosan from shrimp shells and crab shells
•• Microorganisms nourish the roots.
•• Fish marinade
••Humic acid
•• many kinds of useful organic matter.





the top 2 ingredients in pic are peat moss and coco peat.. when i did the slurry i was like this soil seems kinda funny.... slurry ph was 7.2..

when i saw "premium soil" I assumed it was soil.. but..in here Thailand vodka is considered whisky... so i guess it makes sense....

so... what do you think my best plan of attack is? I really have no idea...any advice would great!

Definitely take note of what it is...

As in, don't just do a slurry test without knowing the PH and EC of the water your using

my dumbass didn't ph the water before the slurry ....

think I'll try again tomorrow... lol

Stop flushing with 6.0 pH water. Stop worrying about runoff pH. And stop wasting money on bottles of sugar water like Florakleen.

goldenbags said:

my dumbass didn't ph the water before the slurry ....

think I'll try again tomorrow... lol

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You don't pH the water. You use distilled water.

xtsho said:

Stop flushing with 6.0 pH water. Stop worrying about runoff pH. And stop wasting money on bottles of sugar water like Florakleen.

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As this is my first attempt at growing, I clearly have no idea.. what do you suggest that I do?

goldenbags said:

As this is my first attempt at growing, I clearly have no idea.. what do you suggest that I do?

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I would add nutes and feed not flush. They don't look that bad I only see some issues with the older leaves on the one plant. Nothing that would be resolved by flushing with 6.0 pH water. Is there a reason you're using RO water? Are you on a well?

xtsho said:

I would add nutes and feed not flush. They don't look that bad I only see some issues with the older leaves on the one plant. Nothing that would be resolved by flushing with 6.0 pH water. Is there a reason you're using RO water? Are you on a well?

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Yeah, ro water was meant to work better with advanced nutrients-ph perfect.