• Come join us as we welcome Horticulture Lighting Group to the Autoflower Network!

    We have an official representative from HLG that will be active on the forum to answer your questions, several units that are coming for our official product testing (grow and show's,) and we'll be working together to provide better information on lighting in general!

    Come say hello!
  • Do you LOVE AFN?? bighug We do too!! But we need your help to keep the servers running!

    If you feel like AFN has been useful in your journey and would like to help us pay some of the bills, we have a gofundme page setup for donations.
    Any amount that you can spare will be gratefully received

    Click [HERE] to donate to AFN

Let's discuss pH range in soiless/hydro setups

YouDon'tKnowMe

Auto Warrior
Joined
Apr 28, 2013
Messages
101
Reputation
0
Reaction score
1
Points
0
So I'm sure the vast majority of us are familiar with this image (just without my pretty lines)



Now the vast majority of growers I've seen in soiless/hydroponic setups use something between 5.6 and 6.2, myself included (I always strive for 5.8). But after staring at this chart and doing some long overdue in depth reading about nutrient/nutrient uptake in general (spurred on by my issue with a UV sanitizer), it would seem that the ideal pH range would be something closer to 5.5. There is nothing on this chart that isn't absorbed better at 5.5 than 5.8, and at 6.2, only potassium and manganese appear to be have a slightly higher rate of absorption.

However, as all the charts I look at are slightly different from each other, and leave off a lot of other minerals our plants require/desire, I was wondering if anyone has a more complete chart or one that can be declared properly definitive.

Along with that, I know I've seen some growers who keep their solution at 5.5 and I've read about others as low as 5.2 even. However I'm wondering if there are other risks/benefits involved at lower pH's, such as the acidity maybe doing bad things to materials in contact with the solution (though I assume such a small change from say 5.8 to even 5.2 couldn't make much difference, even if the scale is logarithmic), or if it created a climate better or worse suited to beneficial or infectious bacteria/pests.

So what do you guys think of all this hoo-hah?
 

Muddy

Proud deplorable!
Joined
Jan 7, 2011
Messages
8,674
Reputation
0
Reaction score
1,694
Points
0
Currently Smoking
OG Kush, Deep Cheese, Key Lime
In Pro Mix, which is considered semi soil less, I've found the best pH range to be between 6.2 and 6.5. Below 6.2 I start to see nutrient lockout, mainly P and K. The starting pH of Pro Mix out of the bag is usually 6.9 - 7. I done a lot of experimentation looking for a good way to lower the starting pH. After trying sulfur and cottonseed meal, I've found aluminum sulfate works best. Four grams of 17% aluminum sulfate per gallon of soil mix and feeds of 6.5 have shown that the pH will drop to 6.2 the day after feeding, then slowly rise to about 6.6 as the soil dries out. This cycling through the pH range seems to work best and is much easier to accomplish than trying to get to a set pH and staying there. Same applies to hydro. Cycling between about 5.6 to 6.2 allows the plants to uptake the whole range of nutrients. This cycling seems to be a fairly new "concept" among mj growers. My experiments are on going but at this point, I'm seeing some good results.
 

Bigc

Auto Warrior
Joined
Aug 31, 2013
Messages
102
Reputation
0
Reaction score
15
Points
0
I've been thinking that ph cycling could be beneficial aswell, might give it ago, I'm in coco aswell so could alternate every feeding
 
P

phoenix rising

Guest
I'm about to tier transplant into final pots of pro mix box, like the pro mix but always seem to have ph trouble. I'd like to try the aluminum sulfate addition as an experiment but can't find any in the local shops
I found some epsoma soil acidifier which is sulfur would this work? Package says 1 tblspn per 4 inches of pot diameter.how did sulfur
work whenu tried it muddy?
 

Muddy

Proud deplorable!
Joined
Jan 7, 2011
Messages
8,674
Reputation
0
Reaction score
1,694
Points
0
Currently Smoking
OG Kush, Deep Cheese, Key Lime
Sulfur does work but it takes too long to become active. If you're going to use it I would suggest you mix your soil at least a month ahead of when you plan on using it to give it time to become effective. Keep it moist. That's the reason aluminum sulfate works better. It starts to work as soon as you water the soil. You won't likely find it in the big box stores. Best to look at green house supply stores, garden centers or nurseries.
 
Top