PH problems in soil, help a newbie out

[jacklebee]

Hi, so this is my second grow in a grow room and I keep having soil pH problems. I need some help from professionals, let me start with some backstory

Background as follow:

I completed my last grow with various issues. I was using local peat soil for tomatoes, with a pH level of 6.2 at the beginning.

I gave them one course of generic tomato fertilizer, which I might have slightly overdone with due to reading the package wrong and then immediately got the HESI brand complete package and added that as per instructions on their booklet. measuring the HESI added water gave me a pH reading of 6.4-6.5sh, so very nice, but it seemed that the plants were only getting worse. pH in runoff dropped to as low as 4.9 in on pot and 3.9!!! in the other. Leaves yellowing, calcium, nitrogen deficiencies, etc. Full flower at this point, week 5 or so into flowering.

What did I do? Got a water pH meter, registered the low pH which confirmed my concerns. I also measured my tapwater, which came in at around 7.7pH, so I flushed my pots with the tap water, about 2-3x as much tap water as the pot can hold, whilst removing the runoff water from below.

This didn't do anything to the soil runoff pH (which stayed the same), so I got some pH up from my local grow store. I waited a week for the soil to dry out, whilst the plants were getting slowly more yellow. I added the pH up (biobizz) to the water, raising the water pH to around 8.7, added some Canna calmag once (I thought it would help) and added it to my plants. This actually corrected the pH of the runoff to around +1pH, so 5.9 (mind you I was currently dealing with the first pot), but the plants hated it, probably because the pH of the input water was so high. A week goes by and the first plant starts getting green again, better than before, and I only added regular 7.7 tap water at that point, because lowering that with phosphoric acid seemed like it would further lower the soil pH? The first one was actually fine, after correcting the runoff pH to 6.2sh and having kept feeding it with HESI fertilizers once weekly and the 7.7 tap water otherwise.

The second plant I started correcting later, because it started yellowing later, but I never could correct it, before the end of flower, because the pH had gotten so low.

In my clones room, every new plant, that I start with peat soil would start yellowing pretty quickly. It seems that the pH is kinda getting lower, not higher, as I would guess from the 7.7 tap water? Adding pH up, so the water is 8.0-8.5pH would first really hurt the plant, but then the runoff pH would rise to about 6.0-6.5 range and then watering it with my normal tap water of 7.7 for 1-2 weeks - the plants would actually get better and greener again.

Question that I don't really understand --- Why does my soil pH keep lowering so much when adding any nutes? I am certain, that I am not overdoing it with the nutes. I have phosphoric acid 60% on hand to lower the tap water to 6.4, but it seems illogical to me that when I have low pH problems, I will have to lower the tap water pH, which seems to me that it should in turn be lowering the soil pH as well. But adding any pH up to the tap water, will raise it to an absurd pH, which corrects the soil, but hurts the plants in the short term and then further non-altered tap waterings would make the plant happy, because the soil has an OK pH.

My tap water seems to lower it's pH dramatically very fast, is my gut feel, so it doesn't seem to have much minerals/etc in it, so very low in buffering capacity. Does this seems correct?

So how do you guys do it, when your tap water is above 7 and your soil pH keeps lowering?

My tap water analysis is as below

EC - 420 μS/cm (haha)
pH - 7.4pH on paper
Ammonium - <0.05
Nitrates - <0.010
Iron - 17 μg/l

PS. I just started with my second grow, with the Canna Terra Professional+ soil and after the third round of HESI TNT 50ml/10L (I use 4L, so 20ml per my pretty huge, I guess 30-35L? soil pot) the runoff pH is already at 5.6.

 

[GNick55]

Hi, so this is my second grow in a grow room and I keep having soil pH problems. I need some help from professionals, let me start with some backstory

Background as follow:

I completed my last grow with various issues. I was using local peat soil for tomatoes, with a pH level of 6.2 at the beginning.

I gave them one course of generic tomato fertilizer, which I might have slightly overdone with due to reading the package wrong and then immediately got the HESI brand complete package and added that as per instructions on their booklet. measuring the HESI added water gave me a pH reading of 6.4-6.5sh, so very nice, but it seemed that the plants were only getting worse. pH in runoff dropped to as low as 4.9 in on pot and 3.9!!! in the other. Leaves yellowing, calcium, nitrogen deficiencies, etc. Full flower at this point, week 5 or so into flowering.

What did I do? Got a water pH meter, registered the low pH which confirmed my concerns. I also measured my tapwater, which cam in at around 7.7pH, so I flushed my pots with the tap water, about 2-3x as much tap water as the pot can hold, whilst removing the water from below. This didn't do anything to the soil runoff pH (which stayed the same), so I got some pH up from my local grow store and waited a week, whilst the plants were getting slowly more yellow, the soil dried out. I added the pH up (biobizz) to the water, raising the water pH to around 8.7, added some Canna calmag once (I thought it would help) and added it to my plants. This actually corrected the pH of the runoff to around +1pH, so 5.9 (mind you I was currently dealing with the first pot), but the plants hated it, probably because the pH of the input water was so high. A week goes by and the first plant starts getting green again, I only added regular 7.7 tap water at that point, because lowering that with phosphoric acid seemed like it would further lower the soil pH? Second plant I started correcting later, because it started yellowing later, but I never could correct it, before the end of flower, because the pH had gotten so low.

In my clones room, every new plant, that I start with peat soil would start yellowing pretty quickly. It seems that the pH is kinda getting lower, not higher, as I would guess from the 7.7 tap water? Adding pH up, so the water is 8.0-8.5pH would first really hurt the plant, but then the runoff pH would rise to about 6.0-6.5 range and then watering it with my normal tap water of 7.7 for 1-2 weeks - the plants would actually get better and greener again.

Question that I don't really understand --- Why does my soil pH keep lowering so much when adding any nutes? I am certain, that I am not overdoing it with the nutes. I have phosphoric acid 60% on hand to lower the tap water to 6.4, but it seems illogical to me that when I have low pH problems, I will have to lower the tap water pH, which seems to me that it should in turn be lowering the soil pH as well. But adding any pH up to the tap water, will raise it to an absurd pH, which corrects the soil, but hurts the plants, but corrects the soil and then further non-altered tap waterings would make the plant happy, because the soil has an OK pH.

My tap water seems to lower it's pH dramatically very fast, is my gut feel, so it doesn't seem to have much minerals/etc in it, so very low in buffering capacity. Does this seems correct?

So how do you guys do it, when your tap water is above 7 and your soil pH keeps lowering?

My tap water analysis is as below

EC - 420 μS/cm (haha)
pH - 7.4pH on paper
Ammonium - <0.05
Nitrates - <0.010
Iron - 17 μg/l

sorry but i can’t read all that at the moment just post a bunch of pictures of plants, close ups too, from above looking down etc

 

[jacklebee]

sorry but i can’t read all that at the moment just post a bunch of pictures of plants, close ups too, from above looking down etc

I repotted this 1 week ago into canna terra professional and gave it HESI TNT, since it started yellowing, it's getting greener now, but the soil pH dropped to 5.7.

Main issues on all plants - purple stems and yellow leaves

This gets better initially with nutes, but then gets way worse, when the soil pH drops lower.

 

[GNick55]

I repotted this 1 week ago into canna terra professional and gave it HESI TNT, since it started yellowing, it's getting greener now, but the soil pH dropped to 5.7.

View attachment 2049983

firstly give it a chance to grow.. geez.
secondly what light you got and how far?
thirdly, i have no clue about ph etc i do everything by eye..

 

[jacklebee]

It's a revegged 6 week flower, I'm just trying to do a SCROG build with this one, so training it horizontally. Lumetek professional 300w,

 

[GNick55]

It's a revegged 6 week flower, I'm just trying to do a SCROG build with this one, so training it horizontally. Lumetek professional 300w,

how far light away?

 

[jacklebee]

same light was 80cm away in the clone closet, just moved it into the grow room, now it's 30cm away.

 

[HerbalEdu]

look like your soil isn't buffering pH like it should ...

you need to search google for what you can add to help the soil buffering pH.

 

[jacklebee]

I have the same thought, but what do I do about it? pH down to water to correct it to 6.4pH? That seems illogical to add pH down to a low soil pH.

Conversly adding pH up to 7.7 tap water seems as bad. And since the tap water seems to have super low buffering capabilities, then it will not raise soil/runoff pH at all.

CalMag agent?

 

[HerbalEdu]

i m not a specialist of soil preparation but i know there some stuff that could be added to the soil that will help the soil buffering and stabilize pH. May be someone more experienced with soil prep will chime in.

"How do you stabilize pH in soil?

Overly acidic soil is neutralized with the addition of limestone (available at garden centers). Powdered or pelleted agricultural limestone is most commonly used. Don't overdo lime - it is much easier to raise pH than to lower it."

"Which is one way to increase the buffering capacity of soil pH?

The most common option for increasing pH in soil is calcitic lime, which is available in most nurseries. The amount of calcitic lime you use depends on the soil in your garden or on your farm."

"How do you maintain pH in soil naturally?

Compost and aged manure naturally have a relatively neutral pH, and adding these products to your garden can balance out your pH levels. Compost works more slowly than some other soil amendments, but it creates a long-lasting effect that can improve your garden's health for many years to come."

 

[jacklebee]

I researched lime myself as well, which I have some in my closet, but I guess I can't add it to already potted plants? Plus it seems like overkill, since the soil already states that it has lime in it. I guess I thought I might be doing something else completely wrong and I didn't want to add more variables into the mix.

Thanks for the tip tho!

PS. The CalMag agent I have has 6.8% CaO, which Google refers to as

According to chemical definition, lime is calcium oxide (CaO). In agriculture, lime is usually defined as calcium or calcium-magnesium containing compounds capable of reducing harmful effects of an acid soil by neutralizing soil acidity and raising the soil pH.

So adding that CalMag to my tapwater would possibly be a quick way to buffer soil pH, without waiting months for regular pebbled lime to take effect?

 

[wakey123]

You don't need to check the ph in compost.
Look under the leaves for mites

 

[jacklebee]

I removed the spider mites with neem oil a week ago, the plants doing better now and don't seem to have any left.

Do you think I don't need to worry about pH in this soil? Is it any different in buffering capabilites than peat? This is my first weeks with this specific soil brand, so I maybe I should just wait and see and not worry about the same issues as the last grow?

 

[Imzzaudae]

Hello Jack.
Welcome to the forum. ( Why does my soil pH keep lowering so much when adding any nutrients )
In soil, this can occur when your plants take up particular nutrients, leaving a deficit of others that would lower the pH, or when fertilizers or plant matter break down, releasing Hydrogen ions into the soil.
In an organic grow the plant will take care of it's PH. You need to stop worrying so much about runoff PH.
PH up or down your watering solution after nutrients are in if you like.
If you are using tap water, you must off gas the water at least 24 hours 48 would be better. Your potting soil is living, even a small amount of chlorine will kill off the micro biology in the soil you are trying to feed.

I'd like you to put 1 small potato and 1/8 teaspoon of pink salt in a pot with 3 cups off gassed water and boil it until it is soft.
Let it cool in the water.
Dump the potato and the water into a blender and blend smooth.
Find a plastic coffee can.

Into the coffee can put 2 nice handfuls of the best garden soil you can get.
Real nice black stuff.
Then dump in the potato mash fill the container with off gassed water and mix well.
You are making a 2 Liter batch of this. Don't worry about the tea bag. You can strain it.
Put it in the sunshine or someplace nice and warm for 2 days or so check on it.

When it is ready.
Water your soil with this mixture 9 parts water 1 part microbe solution.
If you strain it and stick it into a bottle and keep in a cool fridge. The microbes go dormant and will keep for a couple of weeks.
Water with this once a week for the next 4 weeks.
After the first watering with microbe solution. Give it 48 hours and water it with this.

Do not feed the plant anything else. Just give it this once a week for a month.
I use Musky fish fertilizer in this solution.
You don't need to make a tea bag just mix and strain it.

You will see a dramatic change in your plant within a day or so.

Your soil is lacking enough microbes. You have been feeding it but there are not enough microbial life in the soil to eat the food your adding to the pot and it's fomenting rather than producing nutrients for your plant.

Adding microbe solution will kick start this process.
Adding the boosted seedling mix will feed all of the microbial life in your pot, add some new life and your plant will love it.
She will green up and start growing for you.

After 30 days you won't believe your eyes.
All the best Ron

 

[Halboy]

sorry but i can’t read all that at the moment just post a bunch of pictures of plants, close ups too, from above looking down etc

Yes, why does soil runoff PH mean anything? It doesn’t. If you’re using soil mix from you back yard you’re going to get bugs in your grow room, your soil may not be loomy enough at some places in the pot, and the soil itself may be way out of PH balance which can’t be fixed through adjusting watering PH. Start with a good PH balanced soil, then water and feed them with PH balanced water, and ALL of your PH problems should go away, leaving you more time to perfect farming skills in other areas, like deciding which terpene profiles are your favorites.

 

[Kamisama]

Maybe carbon can help stabilize PH, I ve used that in water tank (blackjak nutrient) and PH was quite same after a week.

 

[GNick55]

Yes, why does soil runoff PH mean anything? It doesn’t. If you’re using soil mix from you back yard you’re going to get bugs in your grow room, your soil may not be loomy enough at some places in the pot, and the soil itself may be way out of PH balance which can’t be fixed through adjusting watering PH. Start with a good PH balanced soil, then water and feed them with PH balanced water, and ALL of your PH problems should go away, leaving you more time to perfect farming skills in other areas, like deciding which terpene profiles are your favorites.

geezus