PH pen mistake, any help appreciated

I accidentally hit the calc button on my PH pen instead of the power button. I won’t have calibration solution for a week. I have PH up and down. Could someone make calibration solution with distilled water and post the recipe? Or would anyone have any other ideas as how to recalibrate? I watered once and the plants are already showing bad signs. 4 Jack Herer Autos week 6 of flower. 4 Bruce Banner Feminized going to flip when autos are done. Buffered Coco and perlite mix using tps complete calmag and fox farm trio nutes. Any help would be appreciated.


@Urbanartgang there are multiple methods to make calibration solutions at home. Unfortunately, they do require a calibrated pH meter to make them successfully. Without a calibrated meter you’ll just be flying blind trying to make them because even if you follow every step 100% reactions and pH swings will almost always vary without using lab grade equipment and chemicals.

That being said, your best bet is to wait for your calibration solution and just use plain water for a few days. If you know your water pH and the amount of pH up or down you usually use for watering you should be OK just measuring it out.

I wouldn’t suggest feeding though until you calibrate your meter because even just slight over or under measuring with liquid nutrients can cause pretty big swings that will need correction.


Ok thank you. Do you think they will be fine with no food for a week. The ones in flower are in 3 gallon pots and I have to water 1-2 times per day

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@Urbanartgang it depends on how often you feed. Do you feed weekly and water daily or do you feed and water daily?

Feed and water daily. High frequency fertigation style

@Urbanartgang oh man. Yeah. They’ll definitely need to be fed then. What pH do you try to feed at and what are the measurements of each nutrient in the solution? Do you use ml/l or tsp/gal?

I can do some math to get you close but no guarantee it will be in the exact range because of how many variables there are.

I use 2.5 gallons per watering. 5ml of calmag total, 10ml tiger bloom total( tried upping it to full strength but kind of burned them so I keep it half) And 10 ml of of big bloom. Verging ones I use 3.5 ml calmag and 10ml of grow big. De chlorinated tap water, ph around 8.2. I feed the vegging ones at 5.8-6.0 and flowering one 6.0-6.2. Was using 8ml ph down during veg, the flowering nutes must be more acidic so I’ve had to use less. The problem is I didn’t write that down…

@Urbanartgang are you using the hydro trio or soil trio?

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Pretty sure its the soil trio. The two smaller plants 22-25 inches and the bigger one is 33. The small ones look to be about a week ahead of the big ones was going to cut off nutes next week. Should I cut the big bloom out.

@Urbanartgang no. I wouldn’t cut the big bloom out. I would cut back a little on the tiger bloom though because that plant in the back left corner has phosphorus excess. It looks like calmag deficiency but you can tell it isn’t because of the darker brown splotches and the potassium deficiency.

So maybe 5-7.5 ml of the tiger bloom and keep using the big bloom.

Forgot fox farm uses an acidic solution for all of their products so pH up might be needed instead of pH down.

I’ve been fighting high ec runoff with the big one for some reason. In ec is 1.6 and out is 1.1 for the other 3. The big one ec runoff in 2.6

Thanks alot for taking the time to help me out, I’ve really tried to keep an eye on this run. I’ll pick up hydro nutes this week sometime

@Urbanartgang that’s because the big one is locked out so the nutrients it isn’t using are salting up. That one needs a flush. I’d tell you to slurry test your coco but your pen is out of commission. Any litmus strips?

It seems you’ll be OK with the others though just feeding your normal schedule. Cut the pH down to 5ml or just a teaspoon and you should be OK until you can get your pen calibrated.

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I have pool and spa test strips but they only go to 6.2. . Ill cut it down and limp through this week. Watering now so ill flush big one as well. Thanks again

@Urbanartgang you can use the litmus strips for your feed then because you can feed coco up to 6.5 so they’ll work for your feeding until you get your pen going again.

You’re welcome man. Have a good one. Happy growing.

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In a pinch. You can test against rain water.
It should be 6.86 to 7.0
Will tell you how far you are off.

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Well that would be but milk.has pH.of.6.4 so mwbey u could. Try using milk.celebrate. 6.4