Lets discuss container runoff PH

FourOaks · January 18, 2017

Alrighty, here we go.

For those of you growing in soil-less media, and using such fertilizer as Masterblend and Chem-gro, do you, or have you measured the PH of the runoff?

I have ran across this topic as I research growing in straight Coco Coir. The problem is that limited info seems to exist and its limited to those who grow "herbs". If you catch my drift.

The idea is that the soil media will/could/maybe affect the PH of your nutrient solution. So, you compensate by adjusting the PH of your nutrient solution, sometimes beyond what would seem "normal".

Example:

Lets assume you want a PH of 6.0 for your nutrient solution. Supposedly, for Hydro, this is the ideal PH, from what I can find. Lets assume that everything aligns when you mix your nutrient solution, and you have exactly 6.0. You feed your plant, and measure the runoff. Now depending on the media, peat, coir, promix, whatever... your PH runoff could be, say 5.0.

At this point you would have to increase the PH do to the media dragging down the PH. at the root level.

Thats my take on the situation at the moment. The only thing I know to do, at the moment, is to do some samples. Maybe Coir and my homemade mix leftover from last year.

Anyone have thoughts on this. Also, what do you usually PH your solution to?

AKmark · January 18, 2017

I have checked mine, but I do not check it on a regular basis, I was looking for a change in pH as well as rising EC in runoff. All was pretty stable. My solution is 6.2

FourOaks · January 18, 2017

Thanks AKmark.

I might run some test samples in the next few days. Im really curious.

Nematode · January 19, 2017

Unbuffered solutions can swing a lot in the root zone and cause problems.
Chem gro is buffered. I send it in at 6.2-6.5 and don't worry about the drain ph.

Ricky Shaw · January 19, 2017

I also keep the incoming nutrient mix at 6.2 and 6.5 pH and did not sample run-off. I'd felt salts/fert build up could be a problem with evaporation here and off-set that with a larger size container than probably needed. (15gal fabric mainly)

As a control I planted a Sungold F1 in a 20gal, 15gal, and 10gal fabric. All were unpruned and all grew to +7 ft. All pots had about the same amount of solution run through them, even though differently sized becasue evaporation rates on smaller bags is higher. That little fact was somewhat surprising. The 10gal Sungold would lap up 2 gals of feed water just like the 20 gal pot.

I note that, because in essence the 10gal pot was having twice the nutrients run through the media to no detriment of the plant that was apparent. The 30+ pots all had between 160 to 200 gals of solution run through them and they were healthy to the end, with exception of pest damage.

I used promixHP and chem-gro tomato formula,and these are my simple observations. I'm sure results will vary tremendously with different growing medias and fertilizers.

tsipgolf12 · January 19, 2017

Ricky I intend to try chem-gro this season myself and was attempting to figure out how much
nutrient I would need per plant. Is 160 to 200 gallons per plant what you normally see regardless of container size and is that full strength per their instructions.

Thanks RWg

Ricky Shaw · January 19, 2017

First season in containers for me. You seen pictures of the grove? I pull these out like grand-kids photos where ever I go.

So the 160 to 200 gals is an estimate, probably a little on the low side. I hand watered in 2 gal container, they pretty much took 2 gal every day. On a handful of +95F they took 3gals, but very early and very late in the season, 2 gal every other day was adequate. So basically 2gal day X jun/jul/aug = 180gals

My season is pretty short here, a lot of folks probably grow strong 4 months or more and will use more on that account. However, evaporation is high here, and that's a big factor.

Ricky Shaw · January 19, 2017

And yes, full strength per instructions at every watering. With some exceptions for control and observation.

tsipgolf12 · January 19, 2017

Quote:

Originally Posted by Ricky Shaw

And yes, full strength per instructions at every watering. With some exceptions for control and observation.

Thanks Ricky....I would love to have a tomato forest like that myself. Maybe this year

RWG

January 18, 2017	#1
FourOaks Tomatovillian™ Join Date: Mar 2016 Location: NC Posts: 511	Lets discuss container runoff PH Alrighty, here we go. For those of you growing in soil-less media, and using such fertilizer as Masterblend and Chem-gro, do you, or have you measured the PH of the runoff? I have ran across this topic as I research growing in straight Coco Coir. The problem is that limited info seems to exist and its limited to those who grow "herbs". If you catch my drift. The idea is that the soil media will/could/maybe affect the PH of your nutrient solution. So, you compensate by adjusting the PH of your nutrient solution, sometimes beyond what would seem "normal". Example: Lets assume you want a PH of 6.0 for your nutrient solution. Supposedly, for Hydro, this is the ideal PH, from what I can find. Lets assume that everything aligns when you mix your nutrient solution, and you have exactly 6.0. You feed your plant, and measure the runoff. Now depending on the media, peat, coir, promix, whatever... your PH runoff could be, say 5.0. At this point you would have to increase the PH do to the media dragging down the PH. at the root level. Thats my take on the situation at the moment. The only thing I know to do, at the moment, is to do some samples. Maybe Coir and my homemade mix leftover from last year. Anyone have thoughts on this. Also, what do you usually PH your solution to?

January 18, 2017	#2
AKmark Tomatovillian™ Join Date: Jun 2013 Location: Wasilla Alaska Posts: 2,010	I have checked mine, but I do not check it on a regular basis, I was looking for a change in pH as well as rising EC in runoff. All was pretty stable. My solution is 6.2

January 19, 2017	#4
Nematode Tomatovillian™ Join Date: May 2012 Location: massachusetts Posts: 1,710	Unbuffered solutions can swing a lot in the root zone and cause problems. Chem gro is buffered. I send it in at 6.2-6.5 and don't worry about the drain ph.

January 19, 2017	#5
Ricky Shaw Tomatovillian™ Join Date: Aug 2015 Location: Zone 6a Denver North Metro Posts: 1,910	I also keep the incoming nutrient mix at 6.2 and 6.5 pH and did not sample run-off. I'd felt salts/fert build up could be a problem with evaporation here and off-set that with a larger size container than probably needed. (15gal fabric mainly) As a control I planted a Sungold F1 in a 20gal, 15gal, and 10gal fabric. All were unpruned and all grew to +7 ft. All pots had about the same amount of solution run through them, even though differently sized becasue evaporation rates on smaller bags is higher. That little fact was somewhat surprising. The 10gal Sungold would lap up 2 gals of feed water just like the 20 gal pot. I note that, because in essence the 10gal pot was having twice the nutrients run through the media to no detriment of the plant that was apparent. The 30+ pots all had between 160 to 200 gals of solution run through them and they were healthy to the end, with exception of pest damage. I used promixHP and chem-gro tomato formula,and these are my simple observations. I'm sure results will vary tremendously with different growing medias and fertilizers.

January 19, 2017	#6
tsipgolf12 Tomatovillian™ Join Date: Feb 2013 Location: Western North Carolina Posts: 79	Ricky I intend to try chem-gro this season myself and was attempting to figure out how much nutrient I would need per plant. Is 160 to 200 gallons per plant what you normally see regardless of container size and is that full strength per their instructions. Thanks RWg