Coco Coir pH issue - input water runs of a couple degrees pH lower than it goes in

boyblako

New Member
Hi, let me begin by saying I'm a new grower. I'm experiencing some issues with my medium (coco coir/perlite 70/30 mix), and I cannot seem to find any good answers on how to fix this problem. My setup goes as follows: 4 plants, coco coir/perlite mixed, watered every 1-2 days using the "Coco Coir Nutrient Schedule" provided by GrowWeedEasy website (will show up in a google search). It is CURRENTLY (per gallon):

Week 3: FloraMicro, 1/2 tsp - FloraGro, 1/2 tsp - FloraBloom, 1/4 tsp - CalMag, 1tsp

(DO NOTE I am watering with plain every other day as recommended). I use tap water, mix General Hydroponics Flora Series Nutes + CaliMagic Sup. 3 gal vol following the guide, then adjust pH to correct levels (5-5.8 sometimes I hit a little further out). Watering enough to runoff 10-30%, then waiting till top inch or so begins to feel dry and pot is light (I use aeration pots, tend to water every 1-2 days).

I began in solo cups first week, no issue. Transplanted to aeration pots once leaves stretched to edges of the cup. No issues first 1/2wk-1wk of watering. I always pH before watering and then test runoff. I recently noticed the water is going in at correct pH then running off couple degrees lower, can't know exactly as I am using the liquid pH tester and the current shade is comparable to the entire lower range of pH shown on the Color Guide. I'd say runoff was about 3-4.5 pH. Not good. So I water at around 6-7 pH next two waterings in attempt to correct issue. It does nothing. Yesterday I flushed with plain pH'd water ~ 6 to the top of the soil each plant, and let them drain thoroughly. I tested this runoff and things looked OK. Until two days later (today) I water them with the Nutes again, and the runoff is back very acidic. Not good.

AS FOR THE PLANTS, no pictures but they honestly look very good, vigorous growth with deep green leaves. Leaves aren't droopy, they point up slight and look very healthy. Although they seem to be lightening in shade, which is concerning me, I am afraid this pH issue is causing some nute deficiencies. I've read some things stating that General Hydro Flora Series tends to spike the pH lower as it builds up, potentially causing some lockout, but what ways could I fix this problem then?
I want to nip this in the butt quickly, and ensure more healthy growth, but I can't find any advice besides flushing over and over, which seems harmful to the plants. I need legitimate advice from a seasoned hydro/coco grower. I have considered buying a new batch of top quality coco and perlite, preparing it and transplanting, but I want to know if the current situation is salvageable or if I am perhaps doing something wrong.

Thank you for all help in advance!
 

boilingoil

Well-Known Member
Don't trust run-off as an accurate measure of you root zones pH.
You should be feeding every watering, no plain water feedings. ( At least a light nutrient strength even when flushing.)
Depending on the plant to pot size, It's hard to go 2 days between feedings in coir. Drys out and then you have problems with nutrient build up in it.
Your running tap, do you have an idea what's actually in it ?
pH should be 5.8-6.0
So if your going by info from that site it's just bad info.
 

boyblako

New Member
@boilingoil I do not know whats present in the water, no. I will take your advice in tow. As for watering, I only waited two days one time, every other watering has been within 30 hrs of the last, you're right about coco needing water pretty much daily. I understand that runoff in coco is very variable and that its better to test a slurry obtained from the root-zone, however I don't (at this time) have proper water to get an accurate testing. That being said, the problem remains, if my water is coming out so acidic, isn't that an indication of highly acidic medium? And if that is the case what steps do I take to resolve? I will try and get more info concerning the root zone
 
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