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Ph for promix

joe fresh

Active member
Mentor
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i was just wondering, i have always used promix and mixed in compost, and watered at 6.5 and everything was ok.



this time i decided to use just pure promix, and was watering at 6.5ph, but im noticing some def's. some ppl were telling me to water at 5.8 because its a soiless mix.



so my quetion is...what is the real water ph you should be using when using promix?
 

geopolitical

Vladimir Demikhov Fanboy
Veteran
Promix tends be a little on the low side both micro-nutrient and pH wise in my experience. If the only difference between your mix is the lack of compost that's most likely what's at fault here. Regardless of all the soil mixes on here, if your old mix was doing great, go back to it. It sounds simple as you can get. Don't mess with what works.

I personally add compost, dolomite, perlite and a handful of whatever else I have around that looks fun to my promix, but really it's mostly promix & compost. It works great, the plants love it, and I have few if any nutrient problems with it.
 
L

Lloyd_Christmas

I've been using the stuff for a very long time (with only perlite added) and always keep the ph right around 6.0 with great results. Promix is a very forgiving medium ph-wise, keep it right around 6ish and you will be fine I promise.
 

joe fresh

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thx for the quick response guys.


well heres the problem with adding compost and dolomitic lime, my grow is much bigger than it used to be. i have 160 7gal pots to fill. and i dont have much room to mix the compost and promix together.

last run i used the compost and dolomitic lime, but added too much lime and raised the ph of the soil too high, so i had ph problems through out my grow.

so i thaught that if this time i used only promix i would skip right over that problem.

but once again i have problems...
 

SOTF420

Humble Human, Freedom Fighter, Cannabis Lover, Bre
ICMag Donor
Veteran
Problems watering so many plants? :)

Those are big numbers man, in 7 gal's too? Nice.
 

SumDumGuy

"easy growing type"
Veteran
I've been using the stuff for a very long time (with only perlite added) and always keep the ph right around 6.0 with great results. Promix is a very forgiving medium ph-wise, keep it right around 6ish and you will be fine I promise.

I transplanted all my small plants into 5 gallon pots using ProMix. I just dialed it in at 6.0 and they are very happy..
 
L

Lloyd_Christmas

With a grow of that size adding anything besides maybe perlite seems like a chore. These days I mess with coco and what not, but straight promix is by far the easiest medium I've ever used.

Good base nute + pH 6.0 = :plant grow:
 

joe fresh

Active member
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yeah i think i just figured out my problem, now to figure out how it got like that and how to fix it.....


heres what is going on ...just did a runoff test


PH---- going in 6.1---------comming out 4.7


ppm----going in 150(tap water)-----comming out 2000+ppm (meter dont go any higher)


this test was done on the worst looking plant, the one i posted below.


so if you could tell me whats going on to make this happen.....and how should i go about correcting the situation?




ps...for the runoff i made sure to collect atleast 1 Gal of runoff before i tested it
 

joe fresh

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here they are....
 

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L

Lloyd_Christmas

Definitely overfed, you are probably just giving them a bit much food. What nutes are you using and EC/ppm are you feeding at?

If they are burning bad quickly I'd go ahead and flush em if at all possible, don't expect it to be fun though. A couple of gallons of florakleen will help you bigtime. Plain water for a while with decent runoff at the very least if there are just too many. That's a lot of plants.
 

joe fresh

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was watering with jacks pro k-trate, and AN big bud.....1/2--1/2 feed @ 650ppm every second watering and always watering @ 6.5 ph

i just dont understand how the ph dropped, and how to get the ph back up....


as for flushing im gonna have to make some sort of makeshift floor with drain.....aaarrgggg:(
 

kaskar

Member
I use promix with added perlite feed dutchmaster gold once aweek .never ph .works good .my tapwater is around 7 ph
 
I

Iron_Lion

thx for the quick response guys.


well heres the problem with adding compost and dolomitic lime, my grow is much bigger than it used to be. i have 160 7gal pots to fill. and i dont have much room to mix the compost and promix together.

last run i used the compost and dolomitic lime, but added too much lime and raised the ph of the soil too high, so i had ph problems through out my grow.

so i thaught that if this time i used only promix i would skip right over that problem.

but once again i have problems...

With 160 plants with ph probs you must rip your hair out. pH problems are the worst, its such a bitch to fix it once they are planted and growing.

They sell soil test kits, I know this time of year you can get them at kmart and stores like that. It comes with a few little viles, you put in a little of your soil mix and a few drops of solution, wait a few mins and it will turn a color telling you your soil ph, it also comes with test solutions to measure the approx NPK of your substrate.
This kit might help you relieve some of these headaches before you plant. they also sell direct soil contact ph meters.

http://www.google.com/products/cata...TP2uHaLgwwW_zYQh&sa=image&ved=0CBAQ8gIwAjgA#p
 

ogsunk

Member
what pro mix do u all use.i have promix bx and it holeds 70% of the water and then my ph goes up to high like 7.5 or higher.win it drys out its at like 6.2 wtf i add lime&Big and Chunky Perlite.not to happy
 
E

emerald city

the way you water and fert in pro-mix makes a BIG differance...A continous feed program of 500ppm will add up differantly depending if you water to leach or not....
I like to run a low continuos feed regime then some dry cycle,in week 3 or 4 ,test run off to see how numbers are looking,adjust fert strength accordingly.
pro-mix hp,gh ferts,1 Tbls lime per gallon=ph 6.3 at the end of run
 

SumDumGuy

"easy growing type"
Veteran
Well I think 6.2 is the buffer zone for promix. I needed to flush all my for plants soon for flowering to begin and I've already poured 30Gal of water at a pH of 6.0.

Water going in was pH6.0 70PPM
Water coming out pH5.8 4100PPM (maybe mix was a bit dusty) as per my meter

After 30 minutes on the pot
Water going in was pH 6.0 70PPM
Water coming out pH6.0 2400 (pH where I want it)

After an hour flushing that one pot
Water going in was pH 6.0 70PPM
Water coming out pH6.2 260PPM (Went up by .2)

I flushed the crap out of that pot and I'll do it one more time as to bring the TDS into the 100's but that pH isn't moving anymore. I think thats their buffer line.

Btw I have the BX with Micorise. The BX if for general purposes and does hold moisture but I'm happy with ProMix. The HP is high porosity which may have been better suited.
 
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iSMOKE.KUSH

Active member
Veteran
i use pro mix, and i was having problems with my plants too. honestly i think something is up with pro mix because i never ever ever had a problem like this before with any of my grows with it. anyway. i used plain water for a weekish and it all cleared up.

good luck.
 

joe fresh

Active member
Mentor
Veteran
Hey Joe,
Do you get good drainage on your HP?


if i water enough, then yes...but because i have no drain in the floor i try not to have too much runoff when i water, as it will soak into the floor in the cracks and spaces between the plywood
 

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