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Newbie, trying to grasp Ph levels when feeding

OK so growing photos in FF Ocean Forest soil and the runoff Ph after regular water is reading 5.3 - 5.5 on most of the plants. I'm about 3 weeks into veg and started feeding Cal-Mag every feeding. About 3-4mL per gallon of distilled water for each plant. The distilled water Ph itself is around 8.2. But after Cal-Mag the runoff is still only around 5.6 or so. Never in 6's. Shouldn't it be around 6.5 to even benefit from the nutes? Should I be using Ph Up to get the water + nutes to read around 9 Ph to start to get around 6.5 at runoff? Or am I figuring this the wrong way?

And second, should I even worry about using Cal-Mag or any other nutes at all using Ocean Forest during veg stage, or does it have everything I need to get to Flowering?

Plants do look good overall.

Thanks

4 comments

Comments (4)

Cap Stone

May 26, 2021

Hi, if you are using distilled water then adding CalMag is a good idea since distilled water contains no minerals.

Distilled water has a PH of 7 that gets lower the longer it is exposed to the air and adding CalMag should not affect the PH as far as I know.

Do not PH Up your water higher than 7 in an attempt to raise your soil PH. If it really is an issue then you should flush your soil with water PH'd to 6.8-7 but I don't think you need to do that just yet. I would first recalibrate your PH pen and double check everything.

Are there any actual problems showing up on your girls? They look good from the picture.

With just FFoF soil, Distilled water and CalMag you should not be having PH issues. Just keep an eye on the PH going in and don't stress about the runoff unless you start seeing problems with your plants.

Kc-JT

May 26, 2021

Replying to

Awesome, great info and much appreciated! My Ph stick could very well be off. It was a cheaper one. I need to test it if a newly opened distilled water is reading 8.2. And possibly invest in a better one.

I did top dress some dolemite lime in too a couple times to bring up Ph levels. Good to know about using Cal-Mag with distilled. Thank you!

Mr. Grow It

Jun 06, 2021

Replying to

@Kc-JT It's best to try to avoid large pH swings since they can do significant harm to the microbes in the soil. Even though you're using synthetic nutrients (which are plant-available), it's still a good thing to try to keep your microbes happy - and alive lol. I personally haven't used dolomite lime to raise pH but many growers report it being tricky to use. Reports of the soil exceeding 7.0 pH and causing lockout issues is common. Then when they try to correct the issue by feeding in at a lower pH, it just swings back up over 7.0. So be careful when using it. Hope your plants are still looking as good as they do in the pic you posted 🙂

Kc-JT

Jun 07, 2021

Replying to

@Mr. Grow It thanks for the heads up! Actually my Ph meter was a cheapie and I invested in one you recommended on here and my levels are actually in the mid 6's now! That said, I'm gonna stop top dressing my soil with limestone at this point. The plants look great. Proud for my first grow.