Normal or Not ?

[Frogster]

Medium/grow method: In Autopots, with airdomes. In a climate controled tent, Soil used - Canna pro plus with extra perlite & pebbles (pebbles ph'd down).

Feed: and supplements used: Complete Ferro range, via a reservoir, measured twice a day, with a deliberate drifting Ph of between 5.6 / 5.9 and EC between 1.8 / 2.0 (see my review for additional details on the nutrients I use, if required)
A little additional Silicone, just to help protect against heat, as I like to run my temps at the higher end of the range.

Water source: standard tap water left to stand 24 hours (as per the requirement of the "Ferro regional adjusted" nutrient used - lab tested and adjusted for my local tap water)

Strain/age: Dutch Passion, "Think Big" Autos. 7.5 weeks from germination.

Light used: 20 on / 4 off, 600w 400v HPS

Climate: Constantly controlled, and measured:- Day 29.5 Deg and 55% RH. Night 24.0 Deg and 55% RH, Good, air movement from fans in tent, etc.

Problem & Additional Information:
So, Esteemed & knowledgeable peeps of the med section

I have a question.....

On 1 out of 2 plants, a few of the larger sugar leaves look like this...

This is only happening on 3 (just 3 of the normal size buds, out of loads).

However, overall, and as you will see below, the whole plant looks very healthy, she is only 7.5 weeks old and according to the seed blurb she should go 12 to 13 weeks. Looking at the bud development I would estimate 11 to 12 weeks.

Again, this is only happening on occasional leaves, on just 3 normal size buds, on outer and inner branches at mid height, under a normal light position and in every other way looking normal & healthy.... apart from just a few larger sugar leaves.

So, The question is this:-

Is she showing signs of coming to a finish?

I would normally think so, but it is very early, even accounting for pheno differences, and, why only on some of the larger sugar leaf on just a few buds ?

Also, in my (limited) experience I would expect the lower fan leaf to give up it's stored goodness to the plant First ! And as you can see, they are all still green?

Other pics...

Thanks
Frogster

 

[namvet25]

Is the plant outside the one with the problem? What nutes and npk value?Useing cal/mag?

 

[Frogster]

The plant was moved outside for the photo, it is grown in a tent.

Nutes are spot on NPK for the stage of grow (requirements vary according to the stage of the grow).

No Cal/Mag required as the nutes are regionally adjusted to take into account my hard water area (higher Cal already in my tap water, therefore less Cal in the nutrient, etc). Lab tested.

 

[KonopCh]

I would not worry about that.
I had more damaged plant at this stage, and she finished really well despite her troubles.

 

[Waira]

Frogster-- where on the plant are these leaves yellowing? ...that's an important clue,... whole leaf pics too, but the close-ups are choice! I think this is a little P defc. kicking in,... get me the NPK#'s on that stuff, you may need to up the PK ratio's now,.... it'd be wise to get an in-pot pH as well, to make sure this isn't some lockout starting up,....

 

[Frogster]

@Waira

Thanks for the reply....

The location of the affected leaves is marked in the pic below. However, it is hard to distinguish them from the normal leaf in the pic as I had to take a pic in tent with lights on so colour looks odd, but it shows the location.

Whole leaf shot as requested, shows two different sugar leaves from the same bud and almost next to each other. I think the left one looks healthy, no tip burn or other problems, the right hand one shows (what I think) is a deficiency, strange so close to each other - but so different.

Details from the Bloom A & B Nutes as requested, I am feeding as per the requirements.

Also giving PK Booster Enriched at the recommended rate, see below pics...

I am also giving (at the recommended rates) some Enzyme Plus - breaks down dead roots, Bio Crop - a bloom stimulator and Bio Roots - a root stimulator, some silicone and a dash of "superthrive".

The reservoir is measuring PH 5.8 and EC of around 2.0 at present and they are taking up feed/water well via the autopots.

Buds are starting to get sticky now, and a lovely smell.... I anticipate 2 to 3 weeks more on full feed (subject to bud swell), and then my plan is to stop giving the PK Booster Enriched in the last 7 days and stop all feed for the last 3 or 4 days, so to finish they will just get water. followed by 2 days of dark before chop.

I am ruling out lock-ups at this stage, as they normally show throughout the plant in one way or another at various stages... at least more than this, this is very localized on a few buds with otherwise very healthy looking leaf.

Hope that helps you with your analysis of the problem Bro ?
Frogster

 

[Waira]

- oh, you're in Autopots! ..I missed that.. niiiiice,... CANNA Pro is true soil, right? not coco,... .... OK, well the nute's look good, but if it's true soil, pH needs to come up into low-mid 6's...was there a pH hiccup recently in the res'? The res' is one thing mate, but in-pot is another tale, even if Ferro is "self buffering" like AN (which really only works in solution with low ppm water).... T and RH% look fine too, so it's not a bad VPD induced thing either likely,... it's pretty high up though, for it to me Mg defc.,... Hmmm, Froggers could you get me a normal light pic of the whole plant? I see other clues, but the HPS light screws up visual diagnostics.... how far away is the light? I do see pale uppers I think,... as of now, I suspect a pH issue in-pot, too low, just on the edge of some P lockout, maybe others..?

 

[Frogster]

Cheers @Waira

Yes, Canna is a true soil. Difficult to pull her from the tent to get a pic currently....

I will raise the ph a tad to low/mid 6's and see how we get on, I don't want to upset the other plant on the same res that's doing just fine.

Only a couple of weeks fattening up time to go, I think we will pull through enough to get there.

I guess I am just pushing for perfection and the max :smoking:. I could chop her at any time over the next few weeks and obtain a decent result from this plant and her sister.

Recently, I have been looking at VPD more closely, and have tools to measure and chart the Temp & Rh at 1 min intervals.... today's example below....

Below is a spread sheet calculator for VPD (not mine - found elsewhere), in addition to just Air temp, it allows for measurement of the leaf temp (taken with an "infared" thermometer) and is subsequently included in the VPD calculation.

I take a mean average leaf temp with an "infared" thermometer (over 10 or so readings, from various points around the plants) and include that.

Over the 9 hour example period (shown above), I obtained a average VPD of around 1.53 (shown below). Ideal for late stage of flowering, or so I am led to believe.

So a few things ticked of the list..... Once again, thanks for the interest, reply and advice....

Update....I ordered a in soil ph tester from Amazon (a decent one - I hope)

Be here tomorrow (with luck).

Much Appreciated, as always.
Frogster

 

[Frogster]

Update

I managed to get a couple of pics of the girls with lights off and tent door open (used a fill light), starting to look better now.... The affected plant is the one on the right.

The soil prob arrived and is reading 5.7, not sure if this is good / bad / normal ?

 

[Waira]

...yup, a bit too low mate, so time to adjust things up,... if you were in reg. pot, I'd say water with 7.0 adjusted water, including Ca-Mg, which should be partly carbonate based... it's the carbonate that directly involved with pH buffering,... In Autopot, I'm not so sure what's best (check the Autopot section out, maybe they have a solution that worked... For sure the res' needs adjustment, and watch it closely to see if it holds,... closing off the valves and letting they dry enough to water/feed with adjusted solution will be faster to treat in-pot,... to force the pH up some, you'll need to make the pH higher than usual, 6.8 - 7.0... a round or two of this to get it to stay is likely,..
Using the A8 is easy, but there's a few tricks besides what the directions say,... it's not a very sophisticated unit, but used right it can do the job well enough! I find to get the best readings, the soil should be med-moist or so, not soggy or freshly watered (I know this isn't flexible in the Autopots), and not any kind of dry,.. take readings about mid pot,... Let it sit for a couple minutes to stabilize; you'll notice it pegs out when you put it in, this is normal,... Always wipe it clean with a damp paper towel between readings, and store it fully wiped clean and dry... Buff the tip area each time you use it after storage, tarnish/corrosion will screw up readings!
All in all, there little troubles showing so far, and some of the yellowing is normal as you know,... tops do look a bit pale too, might the pH induced defc., or minor micronutrient defc. (not pH related in this case, simple lack-of most likely),... S, Fe, Zn, are the more liekly ones to start showing defc. at this stage,... epsoms can boost the S (1tsp/L), along with Mg,.. otherwise a dedicated micronute supplement is the ticket I keep some around and feed it weekly no matter what, as preventative measure,.. nearly all of them are immobile nutes, so a steady low level supply is good to have available in there....

Oh, there's some info on VPD in the Reference section here in the Infirmary!