What causes soil acidification!?

mimistow said:

I use biobizz(lightmix) and for feeding biobizz tripack + bioheaven + algamic.Temp is 21-26C when ligts on and 16-18C when off. RH is around 40%. In week 5 to 6 leafs started getting discolorated and having some patches of burn on them that i assume thats its not a fert overdose cause i was very moderate with the feedings.The story goes as follows.I firstly watered too much the sprouted seeds when i put them in the soil then i waited for a month to dry out and i stated feeding them once a week with biobizz starting with 0.5 lts upscaling to 1 lt till now(week7) most of the times i only watered them once a week and let the soil dry a lot causing a bit of droopiness but thats all.After week 5 things started getting worse with the leaves turning yellow from tthe bottom to the top .so in the middle of week 6 i decided to test the soil pH which turned out to range between 5.3 to 5.7 that led me to believe that a nutrient lock out is going on considering things getting worse .Now(week7) im yet in search on how to raise soil pH and why this happened and if thats the root of the problem .The other thing that im thinking is if the tap water im using that has chlorine killed the beneficial bacteria and turned the medium into "dead soil" so it cant manage the ph at itself but even if that happened why pH is so low (below 6) when at the same time the solution im feeding them stands at 6-6.2? tap water pH without and biobizz ferts has around 7.2 pH! Thank you for instance.Ill attach some photos of their recent look(week7).

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slownickel said:

Ran out of calcium. dust with some good lime.

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Mattbho said:

You can tell they drooped more than 1x by the early yellow fan leafs .

Ride it out ..
5 is early to be getting yellow leaves but week 7 your almost done!!

If reusing the soil after this grow it will definitely need some work. How did you ph your soil?

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thailer said:

chlorine chloramine are not toxic to plants at the levels that are in drinking water. i had a different source that said the organisms are protected by the organic matter but i found this quick read article that says chlorine and chloramine are safe at the levels used for tap water. https://www.gardenmyths.com/chlorine-chloramine-plants/

i think it is mostly for compost tea and when using microbe innoculants that you should remove the chlorine because they are not protected by the organic matter in the soil.

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mimistow said:

yeah you are right ,althouhg what could cause such a low ph in the soil?

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flylowgethigh said:

The dirt I got from a pond to raise another area had a low PH like that. I tilled in a bunch of ag lime (it comes from a limestone quarry BTW), but the chemical process is rumored to take a few months. Meanwhile the growth is slow and yellow.

Would adding some baking soda to the water before watering do any good? That may fix the PH quicker, but I have no idea if it can hurt.

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G.O. Joe said:

Certain fertilizers change the pH one way or another as part of the plant/root zone nutrient metabolism. No idea whether your fert will always do this if unflushed. You need runoff when you water.

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G.O. Joe said:

It boils down to an imbalance between H3O and OH. You do not have enough buffer capacity for the acid produced by the plant under the conditions you're using. There could be many reasons.

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