How to test water ph without ph meter

I was recently looking into information on how to grow cannabis and I was just wondering if I needed a ph meter or if its another way. Also is there a way to lower and increase the water ph without ph up or down.

Welcome to the forum @WeedGuru
If you want to grow good weed you will need a pH tester. You can muddle through most everything else but without the tester you will eventually have problems.
There are test strips which are cheaper but far less accurate for growing.
There are alternatives to pH up/down. However you can buy small containers of it and it lasts a long time. You literally just use a few drops in most cases.
You could use Lemon juice or citric acid or vinegar for down…(think acidic)
I believe Baking Soda for up


Thank You.

I heard citric acid works for down i use hydrated lime from ag store for ph up. I put a spoonful in a jar of water and shake, let the heavy stuff settle and the water is now ph 12 so works great for me.


Welcome @WeedGuru! If you grow your weed in a living soil, and you have good clean tap water, you won’t need to worry too much about pH and PPMs and all of that on a daily basis. You’ll check and adjust the pH of the soil to begin with, but after that as long as it stays healthy your water won’t change it.

But, it’s still important to have these tools on hand to check things from time to time. I’ve used my pH meter to check on batches of my hot sauce to test for shelf stability and things like that.


The pH of water comes from the charge of the dissolved ions of the minerals it contains. When you’re watering with plain water and it’s clean, it doesn’t really “have” a strong pH of its own.

Now if you use the fertigation salts, like the bottled nutrients, because of the dissolved solids it will have a stronger pH, and you need to test to make sure it’s not having a negative effect in your substrate.

Dont skimp on the PH meter Aprea make a good one they are around $50 maybe less if you look around.

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A ph pen is a must if u want ur water to be right on par but if u sont want to use ph up or down there are some things u can use lemon juice to bring ur ph down and bicarbonate solution to raise ur ph

Cut up or grate a red cabbage and place it into a clear glass bowl. Boil about two cups of distilled water in a separate pot. Pour the boiled water over the cabbage. It should just cover the cabbage. Stir occasionally with a wooden spoon and leave the cabbage in the water for about 30 minutes.

A chemical reaction in the cabbage causes the pigment molecules to change the color of the distilled water. Next, strain off the liquid which has become a purplish red color. This liquid is now your pH indicator solution

Pour a small amount of the water you are testing into a separate clear plastic or glass container. Put a few drops of your indicator solution into the water you are testing.

The watercolor will change and give you either an acidic (red or pink), a neutral (purple), or a basic alkaline (greenish-yellow, blue, or bluish-green) color measurement. Match the color of your water against a color chart to determine the approximate numerical value on the pH scale.



Great tip @Caligurl for making a home made pH indicator solution, search for pink for a good plant pH of between 6.0 and 7.0… :grinning::nerd_face::mag_right:


Recently, while reading all available forum postings, or some link, I read a mention of supplementing SEA-WATER into the watering/feeding. Any similar postings/readings/thoughts?

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Hmmm, I have not heard of that. Except maybe asparagus plants. It kills the weeds and the asparagus tolerate the salt. Roundup alternative so to speak.

I do custom aquariums in offices and I think that high ph and high salts would quickly become a problem on canna plants. In sea water the ph is pegged (buffered) at 8-8.2 by saturating the water with bicarbonates. And almost 3/4 a cup dry salt mix. There are lots of sodium and chloride ions released from the plethora of ionic salts in sea salt. It’s literally the sump of the earth. No bueno. I think there are better ways to take advantage of the oceans trace elements plethora. Like green sand or kelp. Azomite or bentonite would both have similar trace elements make ups. The only reason I could think to add sea water would be for all the trace elements. But I humbly feel those other alternative would give the same results without all the salt and extra bicarbonates in seawater.

That said, I often quick rinse spent aquarium carbon (charcoal just like can odor filters) to remove the salinity. Sea water is loaded with calcium and magnesium and tannins and nitrates that all concentrate in the char/carbon. As a matter of fact live coral devour Ca and Mg faster than cannabis plants and it has to be supplemented daily on dosers sometimes. Anyway, that spent aquarium carbon is officially preloaded char, especially heavy with cal and mag.

Speaking of kelp, I don’t get why people buy expensive jugs of predigested kelp as enzyme boost and trace elements. Dried kelp is like 15$ for 600g of dried kelp food grade. Cheaper for bulk. Personally it’s about an hour drive to the coast. Whenever there’s a big storm and I want to take the kids to the beach in the winter I throw 4-5 buckets in the back of the truck. The beach is covered with ripped up kelp floats and eel grass trimmings. I cram them into the buckets and let them become kelp goo before I pour them out on the raised beds in a rain storm. Yummy stinky goo. The plants seem to dig it.

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The trace mineral was the factor for use.
All you mention is correct.
“Law of the Minimums” was taught to me in 1973.
Beach not far on this island.
Thank you

Nice, I see you are in the PNW. I am just a little N of seattle. I am an avid diver myself. Nice to meet you. I was an ochem major at UW in the 90s and I tend to over explain things out loud in my head. Happy growing and diving. Are you a commercial deep diver or just for fun?

This works for me no calibration, always accurate.