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Riff Raff
08-09-07, 12:57 AM
Right, here's the problem.

My plants seem to be getting yellowing of the leaves pretty much as soon as they go into flower.
It starts at the bottom with the fan leaves and quickly spreads up the plant and soon starts to affect the secondry leaves.

Now i'm thinking N deficiancy.

I'm using bio-bizz grow and bloom and pk13/14.

They get fed every 3 days roughly at a rate of 1.5ml grow and 2 - 2.5ml bloom plus the pk when needed, but it makes no difference to the yellowing.

Now, the Ph of the soil is about 7.2, which i'm thinking is a little high.

Is it too high? Could this be affecting the uptake of the nutes?

Sorry no pics at the moment, will try and get some up later.

Just really need to know if my Ph is a bit on the high side and if so, what can i do about it.

Cheers folks.
RR

asci
08-09-07, 11:04 AM
If the yellowing starts at the bottom and is working it's way up then I'd agree it's N def. This could be caused by a number of reasons.

Is she roote bound? (too small pots)
Has she been over fed so the salts have built up killing off the uptake?
Have you tried applying epsom salts?

lkdj2003
08-09-07, 01:40 PM
In future why not try doing what i do and that is as soon as i start to add the PK 13/14 to the mix i drop the bloom nutes alittle. As you say it could be slightly over doing it and locking out Nitrogen. I would try 1ml grow and 2ml bloom per ltr when not using the PK 13/14. When your using the PK 13/14 for a week or how ever long you use it i would drop the bloom down to 1 1/2ml per ltr until you stop using the PK 13/14 and see how that goes.

Riff Raff
09-09-07, 12:33 AM
Cheers asci & lk.
I don't think :confused: its over feeding, I've been gradually building up to the levels i mentioned.
I've ruled out pot bound, the roots are cool.
I've given 1 dose of epsom to 4 of them a couple of weeks ago-1teaspoon/5litres (is that right?)

On a couple of the leaves the actual veins have gone yellow while the rest of the leaf surface has remained a pale green.

I'll get some pictures up but in the mean time i'll try lowering the bloom levels while using the pk and give them a drink of plain water.

About the ph. is that an okay level?

I'm trying to eliminate all possibilities cause this happens quite often to my grows.

asci
11-09-07, 07:28 AM
def need some pics matey...
I've heard of the bio bizz range being a tad short when it comes to N. You may find since giving the epsoms it should clear up.. The soil should be able to cope with the ph so I doubt that's to blame.

Diaper
11-09-07, 08:35 AM
Yellowing shortly after flowering when using Biobizz?
Sounds a tad familiar!

What soil are you using, and when/how much were you feeding in veg?
I've found that when using a multipurpose compost rather than Allmix feeding levels can be increased to 2ml grow/L before going 12/12. If you look at the biobizz schedule for lightmix you'll see the increased levels there too.

Riff Raff
12-09-07, 03:36 PM
Diaper, asci, sorry for not getting back sooner.

Yep its a familiar story all right.

Soil- J A Bowers with sincro boost(?) and to that i mix in J Innes No3. and perlite.

Didn't feed at all during veg, successive potting kept them nice and green.

Is it possible that the bloom feeds and pk13/14 could be locking out the nitrogen and as lk suggested to lower the bloom while using the pk.

This happens all the time as soon as the plants go into flower.

Feeding shcedule- Started with 1ml/L grow & bloom

Over the weeks its been raised slowly to 1ml/L grow and 2ml bloom.
I raised the grow mix to 1.5ml because of the yellowing but it makes no difference.

At week 3 i've added .5ml pk13/14 for a week
Week4 1ml pk and for week 5 1.5ml pk. I thought i'd spread out the pk feed over 3 weeks rather than 1. Is this cool?

The pk is getting mixed in with the grow/bloom.

Heres a couple of pics
https://www.thctalk.com/gallery/data/500/IMG_3223_resize.JPGhttps://www.thctalk.com/gallery/data/500/medium/IMG_3220_resize.JPG

The yellowing appears to be starting where the leaf stalk meets the leaf blades and rapidly spreading out to the leaf edges.

Thanks for taking an interest folks, it would be good to nail this problem.:D

asci
12-09-07, 04:07 PM
biobizz is famous for a lack of N. Switch to terra veg/flora bro, no problems with that stuff...

Riff Raff
13-09-07, 12:37 AM
Nice one man, will look into that.

Hopefully be starting an indoor grow after xmas so i could make the switch.

lkdj2003
13-09-07, 01:43 PM
Nice one man, will look into that.

Hopefully be starting an indoor grow after xmas so i could make the switch.

Cool, i'll be looking forward to that mate. If they turn out anything like your ladys now, well we are all in for a treat. :toke:

greengiant
20-09-07, 06:23 PM
I have found that with most of my grows the lower leaves start to yellow after about two weeks of flowering. Its mainly the fan leaves which are affected.

During flowering plants do slow down considerably on Nitrogen uptake and use more Phosphorous and Pottasium.

My Chronic are yellowing but it really doesn't seem to be slowing down bud formation at all. In fact these have yellowed more than my Masterkush did yet have much more bud on them.

The other thing is that it allows light to reach the lower buds by dropping the large fan leaves.

I may be way off teh mark, but plants defenitely slow down with Nitrogen uptake during flowering. Perhaps the levels werent high enough before you went 12:12.

I have flushed mine and then fed half strength Vega with PK13/14 and boost and they still continued to yellow slightly. Not rootbounbd either.

Next time round I'm just gonna make sure they are dark green, not light green before I go 12:12. This way I know they have a healthy store of Nitrogen that they can work off during flowering.

Good luck mate

Diaper
20-09-07, 07:57 PM
I may be way off teh mark, but plants defenitely slow down with Nitrogen uptake during flowering. Perhaps the levels werent high enough before you went 12:12.



I don't think you're to far from the mark at all;)

The plants use of N does decrease as it moves into flowering, but it's by no means imediate. Keeping N levels up for a few weeks will always help. Grow a strain several times, and you'll soon get a feel for how to best feed during the transition from veg to flower.

asci
21-09-07, 09:24 AM
I've found that as long as you give them just enough nutrient to stop the yellowing it can be controlled. Since I stopped using any nute or addative the yellowing has already begun on the wr. Madness but then you want this at the end of flowering...

Diaper
21-09-07, 05:07 PM
I've found that as long as you give them just enough nutrient to stop the yellowing it can be controlled. Since I stopped using any nute or addative the yellowing has already begun on the wr. Madness but then you want this at the end of flowering...

You see the plants are still using N in late flowering, otherwise there would be no yellowing.

Just out of interest here are the NPK readings for Bio-Canna vega & flores.

Vega NPK 3.5 - 1 - 5.5

Flores NPK 2.5 - 2 - 5

The concentration at which it's diluted will obviously have an effect on things, but it's quite clear to see that N is still being fed in flower @ similar levels to that of the vegative phase. Not having to mix grow/bloom was a definate plus when I considered replacing my Bio-Bizz knowing there'd be less margin for error without having to do so.

According to the Bio-Canna schedule it's not a straight switch to flores either, they reccomend continuing with vega for at least the first week of flowering.

what I'm getting at Riff, is it's not likely a ph issue but more a feeding one. Like I said before growing out a strain several times gives you the room to tweak your grow each time, and in turn gives you that all important learning experience.

asci
21-09-07, 10:26 PM
and all I mean't was as long as you try to control it, there's never a problem...

Riff Raff
22-09-07, 12:50 AM
You see the plants are still using N in late flowering, otherwise there would be no yellowing.

Just out of interest here are the NPK readings for Bio-Canna vega & flores.

Vega NPK 3.5 - 1 - 5.5

Flores NPK 2.5 - 2 - 5

The concentration at which it's diluted will obviously have an effect on things, but it's quite clear to see that N is still being fed in flower @ similar levels to that of the vegative phase. Not having to mix grow/bloom was a definate plus when I considered replacing my Bio-Bizz knowing there'd be less margin for error without having to do so.

According to the Bio-Canna schedule it's not a straight switch to flores either, they reccomend continuing with vega for at least the first week of flowering.

what I'm getting at Riff, is it's not likely a ph issue but more a feeding one. Like I said before growing out a strain several times gives you the room to tweak your grow each time, and in turn gives you that all important learning experience.


Cheers Diaper, asci, GG & lk

Yep, i'm still on a learning curve with the feeding, and as you say, growing is the only way to iron out any issues. The next grow is getting planned out as we speak.

Might switch from bio-bizz on my next grow and see if i'm any happier using something else.

I've read somwhere that nutrient deficiancy can occur 2 weeks before it starts to actually be visible on a plant. Something to bear in mind.

Anyhows, just discovered a little colony of mites, and bud rot is sure to rear its head soon, so its a case of limping over the finish line.

Don't ya just luv growing, i know i do :D.
Despite all the problems with bugs and mould (& illegality), i can't think of a more enjoyable past-time.
I've learnt more about growing in the past 6 months from all you good people at THC than i could have hoped.

Cheers folks
Good growing and happy toking.:joint::barmy:

Long may THC talk continue :Nice::stoned-smilie::weed:

Diaper
22-09-07, 08:57 AM
Cheers Diaper, asci, GG & lk



Might switch from bio-bizz on my next grow and see if i'm any happier using something else.

I've read somwhere that nutrient deficiancy can occur 2 weeks before it starts to actually be visible on a plant. Something to bear in mind.

Anyhows, just discovered a little colony of mites, and bud rot is sure to rear its head soon, so its a case of limping over the finish line.



Stick with the Bio-bizz unless you';re almost finished the bottle. It's not worth the extra cost of switching just for swithchings sake! Just use this grow as a strting point, knowing that you've room for improvement as far as feeding in veg goes.

The two week thing doesn't sound too far out really when you consider that it takes around a week for plants to show tell tale signs from a feed. Keeping a close eye on things is the only way to really gauge their needs.

Mites you say, well if it makes you feel any better my Bogglegum mothers got a few spots on her leaves. Your best bet will be the rubbing technique to physically remove mites/eggs.

Good luck mate;)