Whats the real optimum PH?

[Strictly_Kush]

This is very confusing to me, I saw a ph chart that says optimum PH is 5.8, the advanced nutrients website says optimum is 5.6, and the overgrow faq on this site says optimum is 5.2..

5.2 ph is 60% more acidic than 5.8 so that is a big difference to plants.. What is the optimum it seems like there are different opinions here...

 

[Captain ChroniK]

That depends my friend...
IMO 5.8 is ideal for hydro and 6.2 for soil.

 

[Strictly_Kush]

Well with soil that I have grown in for 5 years I kept it 6.8-7.0 anything under 6.8 and my plants got mad at me... But Im not talking about soil here.. This is the hydro section :)

5.8 in my hydro grows hasnt been doing the trick, it seems like they like a lower PH than that but now Im confused there is info on this everywhere but its all different numbers...

 

[Venom818]

5.6 to 6.2 works for me but i aim for 5.8

 

[revolutionseeds]

Personally, 6.2-6.3ph in soil. When I do clones in oasis, I water at 5.8-6.2. It depends on the strain.

 

[negative 1]

yeah it really depends on your plants bro. for a generalized multistrain grow i like 5.7 for a week and 5.8 for the next week....hydro. i should also mention that his is my first run in coco / hydro though but after switching to these ph levels the plants look sooo much better. soil....organic i always liked a higher ph at like 6.7. other than that i never really grew any other way but the two mentioned....basicly let the plants tell you what they like is my advice.

 

[Strictly_Kush]

Ok fair enough :) I am growing Blueberry kush cuts and they seem to be happy at 5.5-5.7 range... This is my second hydro grow, my first run with different strains 5.8 was right on.. Its crazy how much difference a few points can make...

 

[PureSugar]

Ok fair enough :) I am growing Blueberry kush cuts and they seem to be happy at 5.5-5.7 range... This is my second hydro grow, my first run with different strains 5.8 was right on.. Its crazy how much difference a few points can make...

What style of hydro are you using? Different mediums and nutrient schedules can effect the pH @ the root level. If you are using a method that allows you to capture some runoff from a plant does the pH level vary from the intial level to the reading of the run off? If it varies by more than .2 then you may want to consider flushing with water pH'd to 5.5.

If your plants keep requiring you to lower the pH of the nute solution to keep them looking happy then most likey your medium isn't properly buffering the nutes and you will run into salt buildup issues.

All that said 5.5 - 5.7 is certainly within the "normal" range for hydro.

 

[~xO Kakalak Ox~]

Just remember if the difference from 7 to 6 is 100 the difference from 6 to 5 is 1000.

For most strains I like 6.0 in veg and 5.6-5.8 in flower.

 

[Strictly_Kush]

What style of hydro are you using? Different mediums and nutrient schedules can effect the pH @ the root level. If you are using a method that allows you to capture some runoff from a plant does the pH level vary from the intial level to the reading of the run off? If it varies by more than .2 then you may want to consider flushing with water pH'd to 5.5.

If your plants keep requiring you to lower the pH of the nute solution to keep them looking happy then most likey your medium isn't properly buffering the nutes and you will run into salt buildup issues.

All that said 5.5 - 5.7 is certainly within the "normal" range for hydro.

Im using ebb & grow 12 site system with hydroton, My runoff goes to a reservoir and Im using Lucas Formula for nutes.. With my last grow DWC 5.8 - 6.2 was fine, with this grow Im seeing that anything above 5.8 and my plants dont like it..

I changed my reservoir today and adjusted nutes down to 5.5 and over the next few days Ill let it drift to 5.8 then adjust it back down again..

 

[WilliamsWonder]

I like 5.5-5.8.

 

[Xceptional]

i'll give you the best advice about ph you can find. set your ph to the lowest possible within the acceptable range for your growing type and let it drift to as high as possible within the acceptable range for your growing type. the reason is at different ph levels different nutrients uptake is optomized. logic tells you that if you let your ph drift from the bottom to the top of the range then knock it back down to the bottom more nutrients get maximized

 

[Xceptional]

to prove what I'm saying take a look at a nutrient uptake at different ph leves as indicated in this chart.

you can see that each nutrient acts different at different ph levels so if you drift from the bottom to the top everything gets a chance to shine plus you are not fucking with your res as often. this is my theory and I'm no guru but again it's just logical and never been challenged when i said it.

 

[PureSugar]

Im using ebb & grow 12 site system with hydroton, My runoff goes to a reservoir and Im using Lucas Formula for nutes.. With my last grow DWC 5.8 - 6.2 was fine, with this grow Im seeing that anything above 5.8 and my plants dont like it..

I changed my reservoir today and adjusted nutes down to 5.5 and over the next few days Ill let it drift to 5.8 then adjust it back down again..

Sounds like you have it under control. A little drift over a few days helps plants growing in hydro setups get the full range of nutes. The "perfect window" in hydro is tiny compared to soil.

 

[lollipopman]

i used to have mine at 5.8-6.0 but now have them at 5.2-5.5, they like it alot better

 

[PureSugar]

to prove what I'm saying take a look at a nutrient uptake at different ph leves as indicated in this chart.
....
you can see that each nutrient acts different at different ph levels so if you drift from the bottom to the top everything gets a chance to shine plus you are not fucking with your res as often. this is my theory and I'm no guru but again it's just logical and never been challenged when i said it.

That is a pH chart for soil but the concept is the same. As I stated above, the window in hydro is much smaller.

Here is a chart that shows both soil and hydro: (originally posted by DazedNconfused)
added a second chart that I find easier to read: (not sure who posted it first but it's in several threads)

 

[ugmjfarmer]

5.6 - 5.8 is my goal, using hydroton drip.

 

[Cat Jockey]

Ahh ... the two charts that do not comport with one another.

The blue chart is from St0ney off of the old HC board and the I have seen the other chart in 10k's posts from OG. I don't know where St0ney got his info and he was not the most experienced grower on HC at the time he made that chart. He was a mod, so that lent credibility to his chart and I think that chart is probably at least 7 years old. No rip on St0ney, just the origins of that blue chart as I remember it. I think the B&W came from a scientific study ... might have the pdf on my hard drive somewhere. And if I don't, I think I have seen 10k post that on icmag as well.

The B&W chart also shows more detail involving absorption rates. It also shows Mg absorption to be the absolute worst at 5.8 pH. I have a strain that shows a Mg def. when other strains in the same tub won't. Maybe I'll get off my ass and run an 'spearmint ione of these days and run two of those plants in different tubs with the same ppm and watch the Mg def as it relates to pH to see if the B&W chart is accurate in its absorption rates.

I dunno. Nutrient companies seem to agree with the blue chart. I run it a bit lower and shoot for 5.1-6.1 and float that range. I have read more than one account from a non-mj site that recommends not letting pH get above 6.2 else nutes will precipitate out. I have also found in the past that if I overshot the pH down, the plants can handle a pH in the high 4's for a few days. That comports with the B&W chart.

So, officially, I run 5.1/5.2 to about 6.1. If it sticks at a range for too many days, I will drop it just to give the plants a different range.

 

[Cat Jockey]

That is what I remember from 10k in support of the B&W chart. Apparently that chart came from a book? I am pretty sure I have read a study done by them edjamacated types that discussed ranges in the high 4's.

I'd sure like to see this discussion grow a bit as there are definitely two distinct camps - the below 5.5 and the above 5.5 folks.

 

[thefabman]

All strain relevant in my book!! From 5 to 7