Growstone pH rise

[terryros]

You don't say what the "few drops" you added were?

I agree that the benefits of Growstones for aeration/water retention, size of particle, weight of particles, and even probably addition of some silicate are nice and that it looks like the carbonates can be buffered fairly easily to control substrate pH. However, the data I have been collecting for a while says that the alkalinity effect of the Growstones is a chronic effect, not a temporary effect of new material. I think you will have to keep adding acidifying stuff long term.

[missbehavecutie]

Originally Posted by edouard1997

Hi everyone,

However the runoff water from the bottom of the pots is 8, ive used lemon juice in addition to the already acidic water which seems to help but the media gets basic again over time. Anything else I can do? I just ordered pH down hoping it will keep the pH more stable instead of it becoming basic again.

my heart is palpitating because i just found out about growstone's ph issue and i had no idea, i thought it was
just like seramis.
Anyways;
i have been doing some research on this and i wouldn't recommend using lemon juice or vinnegar i would us a sprinking of baking soda instead , using lemon juice to regulate the substrate ph will alter the mineral composition which could impede your fertilizer from being absorbed by orchid roots, because certain compositions change the ability of the orchid to absorb nutrients.

the other thing i wanted to mention was measuring run off , its better to measure the ph of the water you use to feed your orchids because that is what your orchids will drink.

good luck ,
Leah

[estación seca]

Like Ray said, this seems to me like an awful lot of work to use for orchids, when much easier-to-use substrates are available. LECA balls are now available at all finer cannabis growing shops.

Desert plants do better in pots for most people with an alkaline pH. Maybe use it on your cactus.

[Ray]

Originally Posted by missbehavecutie

Anyways;
i have been doing some research on this and i wouldn't recommend using lemon juice or vinnegar i would us a sprinking of baking soda instead , using lemon juice to regulate the substrate ph will alter the mineral composition which could impede your fertilizer from being absorbed by orchid roots, because certain compositions change the ability of the orchid to absorb nutrients.

Sorry Leah. I'm not picking on you (although it may seem that way), but this is simply bad info that shouldn't be shared, as-is, so I am taking the opportunity to correct the facts.

► Adding an acidic compound like lemon juice or vinegar - in the concentrations that won't kill the plant - isn't going to change the mineral composition of anything.

► Baking soda is going to affect the pH just as much, if not more, but will cause it to increase, not decrease - just the opposite of what you're trying to accomplish with grow-stones.

► I don't know this for certain, as I've never done so, but I'd bet baking soda sprinkled on potting media can kill roots to which it makes contact. That certainly would inhibit the plants' ability to absorb anything!

► Changes in pH within the pot only affect the orchids' ability to take up nutrients if it makes them insoluble. If you're referring to the classic "pH versus nutrient availability" graph, read this.