Low Soil PH.........How can I raise it ?

[chelsea69]

Hi guys, I was hoping someone could help me this, I've got two plants about fours weeks into flowering. Both are are yellowing rapidly and have been for about two weeks now, apart from that they seem fairly healthy, buds developing nicely and the fan leaves sticking straight out. I know the leaves start yellowing during the flowering cycle, it just seems its happening a bit too soon. They are 18 inches tall, 1 gallon pots in FFOF, I know my pots are a bit small and that could be contributing to my problems, I've been following a tight nute schedule using AN, micro, grow and bloom. I gave them a flush last week using 6.5 ph water, measured the run-off ph and it was 5.0, my question is how can I raise the soil ph?? could i just put water in at say 7.5-8.0 to balance things out, or should I use something else to do it. I'm thinking that the soil being so low is causing lock-out or some other kind of problem.
I'd really appreciate some help with this.
Thank you.

chelsea69 Reviewed by chelsea69 on 03-21-2009. Low Soil PH.........How can I raise it ? Hi guys, I was hoping someone could help me this, I've got two plants about fours weeks into flowering. Both are are yellowing rapidly and have been for about two weeks now, apart from that they seem fairly healthy, buds developing nicely and the fan leaves sticking straight out. I know the leaves start yellowing during the flowering cycle, it just seems its happening a bit too soon. They are 18 inches tall, 1 gallon pots in FFOF, I know my pots are a bit small and that could be contributing to Rating: 5

[Rusty Trichome]

What kind of ph test did you use? The liquid test kits (color-coded results) are skewed by using tinted water, and those cheap soil probe meters are pieces of crap that are not trustworthy. Were you really getting 5.0 readings, all leaves would start to turn bright yellow...and it would happen fairly fast. Are you using any other additives? (CalMag, Superthrive, Sweet, molasses...) Spraying them with anything?

What size pot are they in, and when did you last transplant? (how long have they been in that same soil? Four weeks is a tad deep into flower, but if they're rootbound, transplant carefully...right now, using care not to harm the roots too much. Sometimes you gotta do, what you gotta do. :jointsmile:

If above questions are not helpful, fill-out the troubleshooting form as completely as possible. The more info you provide, the better the possibility of an accurate diagnosis. :thumbsup:

[chelsea69]

Hi Rusty, thanks for the response.
I am using the liquid test kit, when i tested the run-off water i filtered it through kitchen towel first, the water looked clear before i tested it, but i do realise they are not the most accurate way to go.
They've been in 1 gallon pot for 5 weeks, too small and too long in one place i know, but the plants are quite short and i was hoping to finish them in these, though i know i'll have to repot them if i want to keep them really happy. The thing is i've got 6 clones nearly ready to flower and if i go for bigger pots i'm gonna struggle to get them all in my space, so i'm kind of torn about what to do, also i can't get anymore FFOF for a few days.
I haven't used any other additives, just my nute regime, which i've been following rather strictly.
I tested my water run-off again last night and it was just as low as before.
What would happen if i didn't do anything ? would it seriously harm my plants ? would it affect my yield ?
Thank you very much indeed for your help.:thumbsup:
P.S my plants are white widow, so i've got at least 5 more weeks to party time.

[Rusty Trichome]

I am using the liquid test kit, when i tested the run-off water i filtered it through kitchen towel first, the water looked clear before i tested it, but i do realise they are not the most accurate way to go.

Bleach and detergent residue will also skew results. Doubtful it's the soil ph that's out-of-whack. :thumbsup: Have you tried ph'ing plain water through the towel? Just curious...

They've been in 1 gallon pot for 5 weeks, too small and too long in one place i know, but the plants are quite short and i was hoping to finish them in these, though i know i'll have to repot them if i want to keep them really happy. The thing is i've got 6 clones nearly ready to flower and if i go for bigger pots i'm gonna struggle to get them all in my space, so i'm kind of torn about what to do, also i can't get anymore FFOF for a few days.

Going to have to make a decision. Save the time and effort already invested in the rootbound bunch (transplant the adults)...or focus on the new. Or, a combination of both. But in the future, might help to remember that 6 weeks of root growth is 6 weeks of root growth...regardless of size of pot. Plus, a more-confined rootball means less organics (soil) in the pot, so they're freaking-out. Got any old soil you can flush and re-use for transplant? (emergency measure only...not intended as an everyday technique)
Likely this is a major contributer, along with any (incorrect/inappropriate) corrective measures that have already been taken. Not saying that there has been, but thought I'd throw that out there, see if anyone catches it. :thumbsup: It's painful culling a perfectly good plant, but if you can't make it work, they all suffer. Perhaps keep one or two adults, (but keep canopy as even as possible) and concentrate on the clones. This keeps your adults going for earlier consumption than you'd get keeping only the vegging clones. Plus it's a great learning experience, taking them from the plant problems forum, to harvest.

What would happen if i didn't do anything ?

Likely the same thing that's been happening.

... so i've got at least 5 more weeks to party time.

Stress can add weeks to total time to harvest. Fix the situation, and they may finish fine, but late. Doesn't take roots long to realize there's fresh meat available. :thumbsup:

[chelsea69]

Hi Rusty, thanks for the wise and knowing advice, this is only my second grow, so i've much to learn

Bleach and detergent residue will also skew results. Doubtful it's the soil ph that's out-of-whack. Have you tried ph'ing plain water through the towel? Just curious...

I used clean paper towels for the filter, so i reckon my test was semi accurate. i have got some soil left over from my first grow, in that one i used 3 gallon pots and the plant got ridiculously big(lots of nice bud though!!) and hard to handle, so this time i wanted to keep them more manageable, guess i didn't quite plan it out right with pot size, maybe 2 gallon's the way forward for me. As for the clones, they are still in their small pots, i'm thinking i'll go 1 gallon first then move them up into 2 gallon and not flower them all at the same time, keep one as a mother perhaps, i'm already experimenting with a few of the clones, i've topped one a few times and i'm trying out LST on two. i'm still trying things out to see what works best for me, the space i'm using and the plants needs and its all very enjoyable i must say.
Thank you again for your expertise, it's very reassuring to know the fine people on this site will help you out when problems are encountered and do it nicely, without judgement on our own stupidity. Many thanks. :jointsmile:

[Rusty Trichome]

... it's very reassuring to know the fine people on this site will help you out when problems are encountered and do it nicely, without judgement on our own stupidity. Many thanks. :jointsmile:

Yeah...I don't know what got into me. Must have caught me on a bad day. :jointsmile:

[Loafyboy]

Yeah...I don't know what got into me. Must have caught me on a bad day. :jointsmile: