Dinafem cheese with problems - Phosphorus def?

[LoveTheMaryJane]

cheese with problems... Phosphorus def?

about 6 weeks into veg from seed. in Coco/perlite, 70/30 fed as per Canna Coco feed table with:

A & B
Cannazym
Rhizotonic
Magnesium added at .3gm/litre
no calcium added
Drip Clean as stated.

This is a Dinafem Cheese, i think - in the same tent as Original Amnesia, OG Kush, Critical +, Super Silver.

They all show similar symptoms, to a varying degree. This is a Cheese Mother, and is showing the least .. the leaves affected go dark green/ kinda black, then curl and wither.

This is the same feeding regime as Iv'e used successfully for a time now - apart from this grow and the last grow.
Last time, I flushed the lot, and trimmed the dead leaves - and they recovered fine, but I figure I lost about two weeks growth.

This looks like a phosphorous def to me.. the ph in has always been 5.7/5.8 (coco) and the ec on the low side if anything, but near the Canna recommended ...

Two days ago, I gave 3 of them flush, and a dose of Flora Bloom, to boost the P - but no improvement at all today - worse, in fact.

maybe I've moved too soon, but I doubt it.

So, tonight, I flushed them ALL with tap water adjusted to 5.7 with .3gm magnesium, and then an 80% dose of the recommended Canna A&B.

One thing I've always noticed is this: I'll make up the Canna feed, 70 Litres, and let it sit, bubbling, to release any chlorine, and check/adjust the ph to 5.8 or 5.7. Next day, the ph is around 6 or more. This is the reservoir, I'm talking about, and these are hand watered from the res. The ph rises as the days go by.

If this occurs in the Coco at the roots, then the plant will be unable to absorb the P. (I think P only works up to about 6)

Since the last grow, I changed from Canna Pro to Plant Magic Coco which I've used before with o problems. So - I doubt it's the Coco. There's no sign of insects or fungus on these leaves.. or in the tent.

I've used a different reservoir today, just in case there's an infection in the previous one. Unlikely.

The other possibility is that the Canna A&B is past its sell by date. I bought the large size, 5 litres, I think, and been using that for about 13/14 months.

Anyone know if Canna should be used within a certain period after opening? It's always been kept in a cool dark place.

Your comments are MOST welcome!

Nichollette

 

[BudBGrowin]

Re: Dinafem cheese with problems... Phosphorus def?

It seems to me that Phosphorus deficiency looks like a good diagnosis but I am not expert. As for the reservoir I do not run Canna but many other nutes i have used res will rise as they sit out over a few days. I always adjusted the ph back if it ever got too out of whack but I also made sure to mix up fresh nutes every few days so i only used a few gallons. What kind of res are you using and how long does it last (time wise) if you are hand watering? Is it covered?

 

[LoveTheMaryJane]

Re: Dinafem cheese with problems... Phosphorus def?

I just use an 80 litre dustbin, with a lid. I have around 6 plants usually, and I make up 70 litres. That's two waterings, 4 days between watering, maybe 3. So the feed in the res is never more than 4 days old. I do adjust for the ph changes. Back to around 5.7.
There are airstones running in the feed at all times.

If it's a P def - and this is the same feed I've always used - I wonder why it should show just on these two grows? Similar type of plants = 80/20 Sativa dominant, usually. Or there about. White Widow would be the exception, and the yield on that has never been spectacular.

600 watt HPS, intake and exhaust, temp steady at 25 C with blower fan. Humidity about 65%. All tied down, ready to scrog.

They're now in 20L Airpots.

Hope that helps, and thanks for the post!

Nich

 

[BudBGrowin]

Im not sure. from what youve said everything seems to be set up ok. Could just be the specific genetics of the strain. Even within the same strain you can sometimes have variation. Another guess could be that even though the nutes are good going in they might be coming out different. Do you measure your runoff?

 

[KingJohnC]

Your plant appears to have a phosporous deficiency.

here is a nutrient availability chart

here is a cannabis leaf deficiency chart

here is the Cannabis Plant and Pest Problem Solver and the Plant Abuse Chart

Cannabis Plant and Pest Problem Solver - Pictorial

Plant Abuse Chart

 

[LoveTheMaryJane]

Seems to me - phosphorous def right enough. Not because of lack of P, but I was keeping the ph at the lower end, say 5.7 or so. Maybe just out of reach of the P.
Ok. So, from now on, I'm going to nail that ph bang on 5.8. Watering at 5.7 and then next time at 5.9 would seem to be a pretty good idea - what you think?

I measure the ec runoff, and it's usually high. Which would indicate over fertilizing, or lack of take-up in the roots.

I read somewhere (and it makes sense to me) that all the recommendations for ec strength are based on the assumption of a 1,000 watt HPS lamp. The more light, the more ferts will be consumed.

Therefore - using a 600 watt lamp - the dosage should be reduced accordingly, to say 60% of the recommended.

If it's linear, I mean. I'd think it most likely is.

One thing I've not been doing, that I should, I think - is giving them ph adjusted water every third watering.

thanks for all the assistance guys.. appreciated.

And, KingJohn C - thank you for that wonderful combined reference there.. that's a cut out and keep, for sure.

Nich

 

[KingJohnC]

I would adjust your nutrient mixture to pH 5.8.

 

[BudBGrowin]

Are you making sure to water to runoff every time you feed? Sorry I have more I just have been slammed and need a bit to type it up.

 

[BudBGrowin]

If you have high ec readings higher coming out than what you feed with it would definitely be over feeding. How is the PH of the runoff changing? In coco you can water every day if you have good enough drainage. I water my coco plants every 2 days at least sometimes I go every 2 of 3 days. I have read that not watering frequently enough in coco can cause ph swings and lock out nutrients.
As for the light, you might not be exactly right with it being a linear equation comparing the 1000w to 600w. Probably your best bet would be to assume light with footprint. A larger light covering a bigger footprint will be similar to a smaller light in a smaller space. Also 600w lamp is the most efficient of the typical HID bulbs in terms of heat vs light output. If you compare a lumens output chart you will see the 600 scores above a line of best fit for all the lights if that makes sense, meaning more light less heat (although I’m not sure how much of a difference it makes in real life). When it comes to nutrient uptake, I find that heat is the biggest factor in determining the time between watering, not bulb wattage.
Tap water in my experience has a tendency to adjust ph as it sits out. This seems to be due to the electrolytes already dissolved into the tap water. Depending whats in it can affect the ph over days. Usually after 24 hours it will have mostly stabilized. If you put an air stone bubbling the pure water for a few days before you add the nutes it might help. Other than that evaporation can change the water to electrolyte ratio possibly affecting the ph.
5.8 is the best to adjust to because it is right smack in the middle of the ideal range for nutrient uptake. Therefore if you are off a little bit on either side due to calibration or accuracy issues you will be less likely to have a problem. If you look at the nutrient chart King posted up you will see nutes begin to be locked out not far from the ideal PH. There are a few other charts floating around the internet that indicate you have a little more leeway in how much your ph can drift acceptably, but the best bet is to aim for the middle so you have the best chance to hit a good number.

Hope this helps! sorry for the long wait Ive been slammed all week.

 

[stokesy]

I can't be the only one with this problem..which is still present. There's been a big improvement, due mainly to reducing the feed strength.

(I'm the original poster - seems I have two ID's on here... - how do these things happen, I wonder? )


Last few grows have used the Hempy buckets, with perlite and vermiculite, with just two strains - Dinafem Cheese and Dinafem Super Silver.

Things have improved to the extent that I don't have any problems with the Super Silver - but the Cheese starts showing symptoms as in the first pic I published on here, around week 6 into flower, only not as bad....

I'm feeding Flora Micro & Bloom during veg, and the Micro is dropped during flowering period. During flowering, this feed is supplemented with Koolbloom (powder), to give the plant a kick up the arse, every two weeks or so.. Seems to work. I use the equiv of Calmag (with silicon) for each feed.

This is the recipe/method touted by Dalai Hempy, (one of the other forums), and has been my most successful to date.

The grow before the current one - I cut back on the Koolbloom powder - and the results were reduced cola size, and overall quite disappointing......

Clearly, the SS can tolerate the higher strength feed - and on the current feed, I'm dropping the strength of the feed for the Cheese. I also read that the Dinafem Cheese doesn't like a strong feed... (that came from Hygrohybrid, Youtube).

I think the problem is still that the feed is too strong - either that, or there's a ph problem. The feed (hand watered) is always stabilised at between 5.7 and 6.1 - usually bang on 5.8.

Anyone got any comments on any of the above? Looking for info from anyone who's grown Dinafem Cheese...

Thanks for all your input so far..

Nich