pH down question, tap water question

[qpwoeiruty]

1. When you use "pH down", does the plant uptake the "pH down" with the water (and so it would need to have more added with every watering) or does it remain in the soil (and so will acidify the next lot of tap water)? Or to look at it the other way, if you keep using "pH down" will there be a buildup of "pH down"?

2. If you live in an area where the tap water is about 7 (7.14) do you bother adjusting the pH at all or just rely on the compost being the right pH?

I'm trying to learn more about the pH because I still get puny little calyxes on my plants. I get a reasonable weight 20-50g depending on strain and luck from autos but it's not dense. My temps seem marginally high (28ish), my light is a decent brand and spec and I use a load of fresh multipurpose compost with a touch of ericaceous soil to bring down the pH a bit and I use fish/blood/bone in the soil for nutes. I see other people with rock hard nugs and I get weed envy...

[Rwise]

If you dont PH the water then what? The PH rises out of value, right, so PH the water to ~6.5. Many use lemon juice for PH down which I just found that Vitamin C kills chlorine and chloramine in our tap water. The tap water (chlorine and chloramine) can kill all the good living things in the soil.

[qpwoeiruty]

Thanks, I'm using phosphoric acid

[Tedtheclown]

Would you recommend adding lemon juice to your water? Whats the benefits or harms from it? Sounds interesting

[Rwise]

It's organic which some folks go for, I find lemon juice to be temporary. It does not hold the PH level very long. I just used banana peel tea for PH down, dont know that I'll do that again, inside LOL the living stuff in the soil farted up a storm for a bit over 24 hours.

[RetiredGuy]

I am only on my second grow but am a retired chemical engineer so will try to answer.

1) The pH down I use is phosphoric acid. In water you are adding both positive charged H+ ions and negatively charged phosphate ions. The H+. Ions are what decreases the pH. The phosphate ion is a nutrient and will be taken up by the plant. That is why PH changes over time in a DWC reservoir. It is not the PH down that builds up in the plant, although the phosphate might. That is why you should always adjust your pH when watering and also monitor your runoff pH to make sure there is not a nutrient buildup in the root zone.

2. The pH of your tap water is ok, but you also need to be sure that it does not have too much chlorine in it. I use RO water to be safe.

i too want dense buds and lots of them, good luck!

[qpwoeiruty]

A retired chemical engineer who is breakinng bad? Thanks for the info,

[RetiredGuy]

I wouldn’t have anything to do with the shit that Walt made, but I consider growing weed as “breaking good”

[YYCannabis]

Don’t worry about pH down build-up....won’t happen.

But i gotta ask....why do you want tight rock-hard nugs?

[YYCannabis]

Would it make a difference if you knew that small tight nugs are a product of the black market (aka illicit street weed) vendors?
Drug dealers needed to keep packaging small for easier transportation/distribution, and took advantage of the naivety of consumers. They sold people on the notion that tight buds are the best buds, because we consumers didn’t know any better. There was no internet in the 60s and 70s to fact check our dealers, so we bought into their sales pitch.

I know some growers feel that the small, tight nugs have more to offer in terpines or flavor or something....but I haven’t seen any proof of that in my research.

Just some food for thought 😉

[Rwise]

Some strains will simply make lite airy buds, its in their genes, and there is absolutely nothing wrong with them.

[qpwoeiruty]

YYCannnabis, I still think I would end up with the same number of calyxes, just bigger ones which would fill out the space increasing density with the side effect of producing more weed... Is that incorrect?

Rwise, It's all the strains I have grown, too many to be just down to the strain and they are from a variety of different seedbanks. The only thing they have in common is that mine are autos... but even then, I also helped set up a friend in his greenhouse with a couple of freebie photoperiod seeds I had and they came out with undersized calyxes too. It's not the temp because a different friend who I helped set up has a near identical indoor setup (runs at 26c) and he gets undersized calyxes. The two remaining things it could be are related to the nutes and soil... We all used the same nutes and soil, which is 10l erricaceous (pH 5.5), 10l multiupurpose (pH 6.5), 5l vermiculite, two handfuls of fish/blood/bone and one handful of epsom salts. I'm setting my indoor friend up with some pairs of plants because he wants to run a side by side to see if it's the nutes. I on the other hand have confidence in the nutes and think it must be the pH somehow. The pH levels I gave for the two soil types are based on what they should be... I am just trying to generate enough distilled water to do a soil test to make sure.

[dphipps1020]

So your buds are fluffy? What kind of light are you using? Have you tried dropping the light closer during flower? That honestly may be all they need, just a little more light. I just recently started getting fatter, denser buds but I had to upgrade my lights to do it. I was getting good weed before but it was really fluffy because of the lack of light.

[qpwoeiruty]

I have a Mars Hydro SP-3000 @ 45cm from the canopy in a 120x60cm space which I believe is the space it was designed for. It's a decent light by all accounts, upgraded from 3 x unbranded 60w blurples I was previously using. I have seen no improvement from the Mars light though! More leaves for sure, but the bud is consistently loose.

as above - "I also helped set up a friend in his greenhouse (direct sunlight) with a couple of freebie photoperiod seeds I had and they came out with undersized calyxes too. It's not the temp because a different friend who I helped set up has a near identical indoor setup (runs at 26c) and he gets undersized calyxes. The two remaining things it could be are related to the nutes and soil... We all used the same nutes and soil, which is 10l erricaceous (pH 5.5), 10l multiupurpose (pH 6.5), 5l vermiculite, two handfuls of fish/blood/bone and one handful of epsom salts. I'm setting my indoor friend up with some pairs of plants because he wants to run a side by side to see if it's the nutes. I on the other hand have confidence in the nutes and think it must be the pH somehow. The pH levels I gave for the two soil types are based on what they should be... I am just trying to generate enough distilled water to do a soil test to make sure. "

[Rwise]

Pictures may help
45 cm I think is on the high side and could go as close as 31cm (~12"), try letting the plants grow closer or drop it a bit.
What does the soil PH end up at? PH is the most common issue I see posted here. This alone can explain a lot of things, if the cant eat they are not going to grow fat buds.