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Old 05-12-2009, 10:54 PM #11
Oldmac
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yo Row,

The only glass house operator I know in my area doing real organics, is not using pro-mix.
They mix up thier own medium, sterilize it then add amendents that are "live" (like microbes). They devote one house (abt 1/3 acre) exclusively to organics, for the certification process.

Not sure about charts, but I'll take your word for it. Never really thought too much abt looking at a chart, once I tried 6.
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Old 05-13-2009, 12:03 PM #12
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Yes...THAT's the better pH chart Red !

And this is a good discussion / debate topic.

Keep in mind that I'm talking about chem hydro nutes, taking into account that the solution pH will drift within a soil less medium very similar to the pH drift experienced within a recirculating hydro reservoir. I see everyones point about promix being more like a soil medium than a hydro inert medium like lavarock, lecastone, rw or even coco. But throw in the 20 to 30% perlite most folks use and it's suddenly closer to being a high drain inert soil less medium.

Yes, the added dol lime helps buffer the pH from going too low, but in that it's usually sending the pH upward within the medium giving the roots exposure to that drift in pH range. Until the lime is exhausted in the medium, the higher the pH going in will cause the higher pH drift in the medium, which will be a tad higher than what is seen in runoff pH. Or said another way, if it goes in at a solid 5.8 it's more likely to run off closer to the levels where chem hydro elements become much less available. In some ways, if a soil pH test is run the pH found is even higher than what's being seen in the run-off. Later in flowering when the plants are taking in more P than N, that drift may head the other direction, but most growers end up "treating" that by watering in more lime, turning the drift back around and upwards yet again.

Why should the grower chop in half the availability range by setting the initial pH at in the middle or near the top end of the usable range with a start at 5.8, thus letting the pH swing towards what is a danger zone if he's using a chem hydro nute package ?

Getting off more toward a chem nute solution in recirculating hydro purist thought wave..
Not much emphasis is put on Plant nutrition by "mass balance". Mass balance speaks to the fact that plants uptake different elements from the chem solution in hydro at different amounts and differing speeds, leaving behind or taking up more slowly or at lesser levels other elements on their dinner plates. Metaphorically speaking, if you give a child a daily dinner plate with several items on it...say a double quarter pound cheese burger, veggies and a big piece of chocolate cake...chances are he's going to slam down that cake first, then the cheese burger and not touch the veggies. If however, that plate has a smaller cheese burger, smaller piece of cake and the veggies...chances are alot better for him to eat everything on the plate.... Now look at the pH chart for hydro or soil less mediums and draw a line straight up from the 5.8 area to the magnesium and it becomes more clear why so many growers see mag and various other micronute and even P & K defs.

My point (very much up for discussion btw) is that...
Hydro and soil less mediums are certainly NOT flat line like the soil pH chart shows and don't buffer anywhere near the same as soils.
Chem nute packages are very prone to elements percipitating in solution and in inert soil less mediums....above 6.4 is the "danger zone"
And... "there's more than one way to skin a cat" :-)

Arrgh, I'm way over tired and have more thoughts on this but need rest...talk later.

Last edited by 10k; 05-13-2009 at 12:14 PM..
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Old 05-14-2009, 03:37 AM #13
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Thanks for that chart, red! I've been looking for it because I've been searching for the proper PH range for my coco plants. My perpetual SOG began as a soil grow and has evolved into coco grow. Using a PH of 5.8-6.2 still gives me many signs of nute deficiencies such as yellowing and crispy fan leafs and slow growth. I think I'll start to treat my coco mix as an inert hydro medium even though coco is "high CEC" mix and try to run at a lower PH...about 5.2 and see if it drifts up.
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Old 05-14-2009, 05:23 AM #14
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Quote:
Originally Posted by redgreenry View Post
It's my experience running Promix with cheap chem nutes - Shultz 10-15-10 that problems would start when the pH dropped below 6.2. Adding D-Lime and maintaining the pH 6.5-6.8 with better nutes gives me good results. So I'm doing a soil style grow currently with AN nutes.

I think if you want to run Hydro style with low pH, you will have a running battle with the D-Lime as it buffers the pH and will pull it up over time. Promix is a blend of peat moss, vermiculite and perlite with some D-Lime. You could mix your own or try a perlite/vermiculite blend or go to CoCo.
Hi Red,

Thanks also go out to you from me for the chart. Very interesting with what you have said about your experiences too, and your comments abt Pro-mx. I also think going in with a low PH creates a battle and buffering is a perfect way to describe the D-limes function.

I spoke today to a greenhouse grower, he told me pretty much the same thing. Only used different terms; promix has dolomite lime in it, that's to keep it from getting "sour", it will bring it back to "sweet", but also he added it releases calcium and magnesium to the mix. Since a majority of growers are using RO water there is no need to "meter" it into the nutient flow, it's already in the pot.
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Old 05-14-2009, 06:11 AM #15
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Hello 10K,

First I'd like to say I like it here and I think I've found a home.

But damn man, I saw your post early this AM and between reading your post, doing some research and reading more....I started my day late, all 'cause you got me thinkin'. Bothered me enough to go out of my way to see a friend at his greenhouse and ask him about pro mix. Since he used charming terms like sweet and sour I needed to ask him what PH he used. He said "shoot for 6". Told him that somene (Row) had found an info page from a nutrient mfg who recommends 5.8 - 6.5. He said to me "so how much different is that then what I told you? shit, just shoot for 6!" Well, like I said earlier, that's abt where I am now. Since this is a new grow op and we are fighting enviromental problems (growing in the basement from hell) I'm sure that I'm not getting maxium growth ATT so I am not real sure if I'm losing anything to PH.

That might change if I decide to add 20-30% perlite. Actually I hope to educate my partner and start to change over to an aero/fog ponic grow trays I have built and played with but not put into production yet. It just does away with a grow media all together. I'm having a hard time making him rethink all the things he thinks he knows abt growing, but he's comming around.

Thanks for reminding me that I can check the runoff to try and see what's going on. Years ago I had a stick in the soil type PH/mositure meter, and never saw major swings in the promix untill it was about 8-9 wks old then would sart to see a slow but steady climb, abt wk 12 it was offical....gone "sour". hehe gotta' luv it.

Last edited by Oldmac; 05-14-2009 at 06:19 AM.. Reason: forgot a thought I think
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Old 05-14-2009, 06:29 AM #16
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Hey Row,

I think maybe you really found the answer already. I'm just not sure if it's definitive.
Must sleep on it and see in the AM how I feel about this.

Last edited by Oldmac; 05-14-2009 at 02:23 PM.. Reason: should stop typing at some point sometimes
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Old 05-14-2009, 02:24 PM #17
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Eureka Row!

After devoting more then a day thinking, reading and talking about this topic with some other people, and having slept on it (for at least 4hours), I woke up and had me a "eureka moment".

Row, I think you have come up with the most definitive answer yourself, when you found the DutchMasters' reccomendation for Pro-mix. They clearly address soiless mixes, name Pro-mix and give a resonable yet short reasoning behind the recomendation. I happen to use DM products and have never had a problem with them. I use DM Gold in my personnel grow (3 stage Rockwool, drip to waste) and DM Advance with the Pro-Mix. I like and trust this company so I'd go with them on this.

Also you have seen for yourself it ran better at PH of 6 then when stated higher. Why not go to 5.8 and see what happens and if it gets better, drop it .2 more and run at 5.6, etc. Somestime we all just have to experiment a little and find what works best for us and our stiuation.

Great thought provoking thread Row, hoping it continues since I know a lot of people use Pro-Mix, maybe we can get some others to tell us what's working for them.
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Old 05-15-2009, 02:49 AM #18
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Originally Posted by Oldmac View Post
Eureka Row!

After devoting more then a day thinking, reading and talking about this topic with some other people, and having slept on it (for at least 4hours), I woke up and had me a "eureka moment".

Row, I think you have come up with the most definitive answer yourself, when you found the DutchMasters' reccomendation for Pro-mix. They clearly address soiless mixes, name Pro-mix and give a resonable yet short reasoning behind the recomendation. I happen to use DM products and have never had a problem with them. I use DM Gold in my personnel grow (3 stage Rockwool, drip to waste) and DM Advance with the Pro-Mix. I like and trust this company so I'd go with them on this.

Also you have seen for yourself it ran better at PH of 6 then when stated higher. Why not go to 5.8 and see what happens and if it gets better, drop it .2 more and run at 5.6, etc. Sometimes we all just have to experiment a little and find what works best for us and our situation.

Great thought provoking thread Row, hoping it continues since I know a lot of people use Pro-Mix, maybe we can get some others to tell us what's working for them.
Not to diss your "eureka moment"...
But I must say that the manufacturers of nutrient packages tend to recommend pH ranges that work best for their products. You mention that you're using the dm gold line for your rockwool drain to waste. If you run this product at 5.8 instead of DM's recommended 5.5, you are in essence chopping mag uptake significantly and eventually endangering cutting down several other micros, plus p &k as the pH drift goes upwards from your 5.8 start.

As for your use of dm advance line in the promix, you'll get no argument from me as your running the dm products and not the GH Flora series chem nutes, which is what Row is inquiring about here.

For their product line, in their own words, Dutch Masters says...
Quote:
"Check and adjust the pH 5.5 to 5.8 for Rockwool, Perlite, Clay, Aeroponics, Hydro or Coco users. 5.8 to 6.5 for soilless systems such as Promix or Sunshine mix."
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Old 05-15-2009, 06:28 AM #19
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Yo' 10k,

Point well taken about different Mfg may recommend different PH's to more suit there perticular product. So what does GH Flora series chem nutes have to say about promix?

But since Row stated it was better at a PH of 6, what would be wrong with his trrying to go down say .2 next run to see if he gets better or worst results. Might even to go lower in steps......and that puts it closer or even into the area you think is best. This is how I've dialed in or "fine tuned" things like PH or nutes strength. etc, regardless of the media I am using. Using common sence; just like knowing when to water soil container plants.

You mentioned my use of DM Gold in my RW drip to waste, I never said what I use for that. Again what I use there, I arrived at that thru trial and error. As for rockwool; I don't like using it, don't recomend it, pretty much hate everything about....I use it cause it fits my needs, and it fits my GI-grow. It is why I have spent some time money and effort building and experimenting with aero/fog ponic grow trays setup I hope to get up and running soon.

I'm still poking around to see what other Pro-Mix users (you know who you are) have been using with thier brand of nutrients.
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Old 05-15-2009, 07:56 AM #20
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Quote:
So what does GH Flora series chem nutes have to say about promix?
GH flora series is a hydroponic chem / mineral nute package. They say nothing about promix.

Flairform gives plentiful information about optimum pH ranges to avoid percipitation and damaged chem hydro mineral multipart nute solutions...
They advocate running a 5.0 to 6.0 range and proper mixing to avoid such solution damage.
http://www.flairform.com/hints/ph_optimum.htm
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