Raising soil PH 5.5 Pro Mix - Problems in power

[georgebush]

Need some help all, think i have a lockout issue.

So I have vegged for 2 months in 15 gallon pots using PBP and some other supplements in ProMix soil. Through the veg run typical added some PH down to get the PH to 6.4-6.5 range.

Now in the 4th week of flower I'm showing some purpling of the leaves from the center outwards, and also the pistols on my buds are orange/brown and look like they are burnt but not under direct light. This is happening to about 10 percent of the buds over a multiple plants.

I was told this could be Phosphorous lockout due to leaf color. I am using Millz in flower and just started adding C4 at the recommended dose which contains Phosphorous so i don't think its because of a lack of phosphorous but maybe out of range PH.

Soil PH is 5.5 (tested with calibrated Blu Labs Soil meter)
Run off - not yet tested.
Always PHED nutes/water to 6.4-6.5 entire run. (using PH down from AN)
Week 4 in flower.
Also have added about half dosage every other water of MagiCal entire run.
Never had any other issues.

What should i do to raise the PH? Just use PH up?

 

[Emmay_Dee]

Way too acidic for soil. And even more acidic for a flowering plant. You can veg at 5.5 in soil with major Nitrogen and iron but you have to raise it once you flower to at least 6.5 and stop the Nitrogen and iron. Certain nutrients need alkalinity to bind and mineralize.

~Peace~

 

[mdgg4]

Need some help all, think i have a lockout issue.

So I have vegged for 2 months in 15 gallon pots using PBP and some other supplements in ProMix soil. Through the veg run typical added some PH down to get the PH to 6.4-6.5 range.

Now in the 4th week of flower I'm showing some purpling of the leaves from the center outwards, and also the pistols on my buds are orange/brown and look like they are burnt but not under direct light. This is happening to about 10 percent of the buds over a multiple plants.

I was told this could be Phosphorous lockout due to leaf color. I am using Millz in flower and just started adding C4 at the recommended dose which contains Phosphorous so i don't think its because of a lack of phosphorous but maybe out of range PH.

Soil PH is 5.5 (tested with calibrated Blu Labs Soil meter)
Run off - not yet tested.
Always PHED nutes/water to 6.4-6.5 entire run. (using PH down from AN)
Week 4 in flower.
Also have added about half dosage every other water of MagiCal entire run.
Never had any other issues.

What should i do to raise the PH? Just use PH up?

kinda late but lime was probably your best bet if maybe you applied two weeks ago. your in soil so moving your ph up that late will be hard seems like its locked in to that ph due to the peat, next time some type buffer in your mix. also continuous applications of ph up will have no effect on changing your rootzone ph with peat, the peat is just going to stabalize your ph back to 5.5, powdered lime.

PEACE!

 

[georgebush]

kinda late but lime was probably your best bet if maybe you applied two weeks ago. your in soil so moving your ph up that late will be hard seems like its locked in to that ph due to the peat, next time some type buffer in your mix. also continuous applications of ph up will have no effect on changing your rootzone ph with peat, the peat is just going to stabalize your ph back to 5.5, powdered lime.

PEACE!

Gotcha. Is it possible to add powdered lime as a top dressing of some sort on the soil currently or would that just be a waste of time.

Noted for next run to add lime to the promix when potting.

Thanks for the info!

 

[mdgg4]

You can try, but by time it breaks down and become available your plants will be about done.

PEAC!

 

[troutman]

Either use pH up which is a potassium hydroxide solution and/or use lime with your water and flush your pots.

Go slow with both products and don't change the pH too fast.

 

[Calyxander]

I have used ProMix BX for many years now.
I always blend in a very generous amount of dolomite lime.
Never had a problem with PH.
Good Luck!

 

[FunkBomb]

Powdered dolomite lime can be mixed into water or used as a top dress. Either way will help you get your PH back to where you need it.

-Funk

 

[Floridian]

Yea I used to use promix and always had to add at least one tablespoon of dolomite per gallon soil,I normally experienced PH drop towards the middle of flowering.You should get amounts of dolomite per gallon soil from someone that still uses promix.Also if you are not using R/O water yet I cannot tell you how drastically my erb improved,you have to experience it for yourself.

 

[heatherlonglee]

Let the flaming begin!
I don't see nutrient burn or lock out on the tips of your leaves? Not many will agree with this but this is the real truth about Pro-Mix; it's doesn't need to be ph'd. It doesn't need added lime right out the bag. The medium is already designed to keep PH in check all by itself. With Pro-Mix you need to water with RO water and use medium strength nutrient solutions. It's all about the amount of bicarbonates that you put into the mix. A bunch of wrong information around about how to use the Pro-mix. The two main points that are known as common knowledge but are wrong are that you need to PH and that you should feed with pure water; these are wrong! Feeding with pure water/low nutrient solution will cause a PH swing, don't over or under fertilize and the Pro-Mix Ph will stay in check by itself; it's posted on the Pro-Mix site even if nobody likes the info.

Check out this thread about PH and Pro-Mix.
www.icmag.com/ic/showthread.php?t=271663

Also read this from Pro-Mix
www.pthorticulture.com/en/training-...een-fertility-extremes-and-growing-medium-ph/
www.pthorticulture.com/en/training-center/what-is-cec-cation-exchange-capacity/

On to my next rule about Pro-Mix that I think may be your problem. It's looks to me that the Pro-Mix has been drying out to much? If you let the mix dry out completely you'll definitely be getting leaves that look like your photo's. Pro-Mix is designed to be kept moist, you don't need to be watering everyday or every 2 days even, this depends much on environment and pot size; the medium needs to be kept moist while still letting it dry out some but never completely dried. You don't want to let the mix dry out so much as giving the roots time to get oxygen and breathe, then you water them again. If your pots of Pro-Mix are weightless when you water you waited to long.

 

[Floridian]

I'm guessing your definition of R/O water and pure water is different?I know after using R/o my grows improved,but my soil Ph always dropped in flower regardless of nutrient solution

 

[heatherlonglee]

Sorry to take so long to answer! When I say pure water I mean (RO water, tap water, extremely low nutrient solution water below 150ppm) the usual advised cycle of feed, feed, water; that water only cycle will cause a PH swing. It should be feed, feed, medium to low strength feed as the 3rd round, but not so low of a ppm on the water that it messes with the balance of bicarbonates already balanced in the Pro-Mix. I use about 1/4 strength from what I normally use on my 3rd low strength feed. Above 200ppm and below 350ppm on that 3rd low strength feed probably a good starting point. 15%-25% runoff most feedings works for me.

From what I understand from reading through the Pro-Mix literature (lol) it says that that PH balance will get messed up by over fertilizing and or under fertilizing. It advice seems to favor a drain to waste style of growing where you flush old fertilizer (salts/bicarbonates) out the bottom, then the Pro-Mix does the rest. I'm talking about fresh Pro-Mix out the bag, I reuse about 25% from previous grows and just mix in fresh stuff every run. If you've already added lime or are using Pro-Mix from another run this advice is probably not as valid.

Then I just called PT Horticulture on the phone. I asked about 1. reusing Pro-Mix, 2. how long can it be used, 3. does it need to be PH'd? I talked to a older lady for my region.
1. She said not recommended to reuse because most likely will see PH problems.
2. She said Pro-Mix has a life up to around 9 months, can then be added to outdoor soil indefinitely.
3. She said it all depends on the alkalinity of the water that your using. Start with high quality water with low levels of bicarbonates below 150ppm no PH needed. RO water was recommended and that should stop all PH problems and the need to PH.