Runoff Ph Too Low, Don't Know How To Fix It.

[cottageman]

So I've had the same setup for about 2 years and this just started happening recently. We feed anywhere from 5.8-6 depending of the week of flower, we run in 3 gal pots with rockwool. We flush once a week and starting at week 3 we get low ph around 5-5.2. We feed at 6 when we flush and the Ppm readings are more than fine. It's causing the plants to have either a calcium or mag deficiency. What is causing this? The variables that I changed was I switched bases from an sensi to heavy 16. I also added uptake by cyco instead of diamond nectar. Maybe one of these are the causes? Any help would be greatly appreciated!

 

[UncleRomulus]

I’d say one or more of those products raise the ph only for a short time. I’d just put er in the top higher if she’s coming out too low at the bottom, but I understand there might be more to this here

 

[cottageman]

I’d say one or more of those products raise the ph only for a short time. I’d just put er in the top higher if she’s coming out too low at the bottom, but I understand there might be more to this here

Wouldn't humic or fulvic acid power the ph because it's an acid? I'd raise my ph but I'm afraid of feeding higher than 6 in rockwool

 

[chemistry]

When you say flush, do you mean with plain water or your nuit feed?

 

[madgrower]

So I've had the same setup for about 2 years and this just started happening recently. We feed anywhere from 5.8-6 depending of the week of flower, we run in 3 gal pots with rockwool. We flush once a week and starting at week 3 we get low ph around 5-5.2. We feed at 6 when we flush and the Ppm readings are more than fine. It's causing the plants to have either a calcium or mag deficiency. What is causing this? The variables that I changed was I switched bases from an sensi to heavy 16. I also added uptake by cyco instead of diamond nectar. Maybe one of these are the causes? Any help would be greatly appreciated!

Why did you switch bases

 

[4plant]

Are you getting runoff every feed or only when flushing? Humic/ fulvic will lower ph but not raise ec. They might be hanging on inside the pot until you flush them out. I’m currently having some issues dialling in feed vs runoff levels in Rockwool right now but I’m finding 10% to 20% keeps the root zone happy runoff stays almost identical to what’s going in. And I also use humic and fulvic bios. You are in 3 gallon pots filled with Rockwoll cubes?

 

[Bulldog420]

So you have low ph and low Ca?....... Add calcium carbonate. You say possible low Mg, then add Lime. I would wager you are not low on Mg. Seen hundreds of soil tests, and Mg is usually in the toxic range in cannabis grows.

 

[cottageman]

So you have low ph and low Ca?....... Add calcium carbonate. You say possible low Mg, then add Lime. I would wager you are not low on Mg. Seen hundreds of soil tests, and Mg is usually in the toxic range in cannabis grows.

Its not that I dont have enough ca or mg. I have it at max. My ph is too low so its not absorbing calcium or mg, adding more won't solve the deficiency it will just cause more buildup

 

[cottageman]

Are you getting runoff every feed or only when flushing? Humic/ fulvic will lower ph but not raise ec. They might be hanging on inside the pot until you flush them out. I’m currently having some issues dialling in feed vs runoff levels in Rockwool right now but I’m finding 10% to 20% keeps the root zone happy runoff stays almost identical to what’s going in. And I also use humic and fulvic bios. You are in 3 gallon pots filled with Rockwoll cubes?

Why did you switch bases

an sensi had way too much N for me, it was so gunky and expensive compared to heavy plus I know multiple people that grow with their base and they love it.

 

[cottageman]

Are you getting runoff every feed or only when flushing? Humic/ fulvic will lower ph but not raise ec. They might be hanging on inside the pot until you flush them out. I’m currently having some issues dialling in feed vs runoff levels in Rockwool right now but I’m finding 10% to 20% keeps the root zone happy runoff stays almost identical to what’s going in. And I also use humic and fulvic bios. You are in 3 gallon pots filled with Rockwoll cubes?

we only get runoff when we flush for the most part. we will get runoff in regular watering but not usually enough to read the runoff. I have been watering the same way for a long time and this just started happening to me recently, that's why I'm assuming its a nutrient switch.

 

[4plant]

Yeah probly because of the increase in acidic minerals, you could increase the irrigation time to wash out the rockwool a little better.

 

[3 balls]

Could you just wait until the end to flush? Seems like the fluctuations/deficiencies all stem from the weekly flush.

 

[cottageman]

Could you just wait until the end to flush? Seems like the fluctuations/deficiencies all stem from the weekly flush.

no the flush is just where I get to see what is going wrong, otherwise i would have no clue. I will get lockout if I don't flush til the end.

 

[chemistry]

Every time you flush with water you cause your plant to fast, it will show all sorts of defs, that you'll struggle to find a cause for, due to the flush. I flush only with new nuits, never flush with water until the end.

 

[cottageman]

Every time you flush with water you cause your plant to fast, it will show all sorts of defs, that you'll struggle to find a cause for, due to the flush. I flush only with new nuits, never flush with water until the end.

I don't flush with straight water and I cant just not flush, that's how you get nute lockout and kill the plants. They're not completely fasting and I have been flushing once a week for 3 years and this doesn't happen. The deficiency is already there when I flush, me flushing is the only way to know what is wrong in the medium. Not flushing til the end would 100 percent kill the plants, ive tried to skip weeks without flushing and it causes lockout. Even the an and heavy feeding charts say to flush once a week. The deficiency is already there when I flush.

 

[Surfinwstyle]

I don't flush with straight water and I cant just not flush, that's how you get nute lockout and kill the plants. They're not completely fasting and I have been flushing once a week for 3 years and this doesn't happen. The deficiency is already there when I flush, me flushing is the only way to know what is wrong in the medium. Not flushing til the end would 100 percent kill the plants, ive tried to skip weeks without flushing and it causes lockout. Even the an and heavy feeding charts say to flush once a week. The deficiency is already there when I flush.

Hey there. Great thread. Id consider this thread a very advanced one in the Rockwool world. If you can control what's inside your medium, that understanding alone can be a huge game changer. I call it medium control. I'm not sure of the science part of it, but through trial and error, I know what works. I just LOVE IT! Haha. Were you able to figure out what was going on? If not, i'd love to help.

 

[cottageman]

Hey there. Great thread. Id consider this thread a very advanced one in the Rockwool world. If you can control what's inside your medium, that understanding alone can be a huge game changer. I call it medium control. I'm not sure of the science part of it, but through trial and error, I know what works. I just LOVE IT! Haha. Were you able to figure out what was going on? If not, i'd love to help.

Thank you for the reply and I am pretty sure I figured it out, it was a combination of too much humic/fulvic acid and around the same time I brought in clones from a licensed dispensary in Sun Valley that gave everything root aphids so there is your yellowing problem lol

 

[Surfinwstyle]

Thank you for the reply and I am pretty sure I figured it out, it was a combination of too much humic/fulvic acid and around the same time I brought in clones from a licensed dispensary in Sun Valley that gave everything root aphids so there is your yellowing problem lol

 

[Surfinwstyle]

Way to go

 

[cottageman]

Way to go

ill make sure to only buy my clones from Green Dragon and not another shitty dispensary in LA lol. Not only did the clones have Aphids but i bought 2 sherbet clones and they turned out to be 2 completely different strains