Diagnostic Help Please

[jfred]

Forgive me for just barging in (my first post) with needs, but I have some and am hoping there is a good diagnostician here'bouts.

I'm a hobbyist/grower in north central Texas and have good results outside. The deadly (to pot) heat last summer motivated an indoor set-up. I did a test grow on some white widow I had and recently harvested 6 oz/plant. So I thought I had it down.

My present grow has been under the big light about 2 weeks. The seeds germed weak (40% didn't sprout) and started slow but have done well once they got going, except for this one thing that has me concerned for their overall health...

I've posted photos here - 420 Magazine Photo Gallery

Here's my set-up:

>Jack Herer Fem from seed
>Cana medium and nutrients (Rhizotonic/TerraVega) at recommended levels, pH adjusted to 5.5-6.5
>1000w Sodium in an air-cooler hood
>Temp 80F RH 50% average
>CO2 enhanced to 1500ppm

Except for the plant variety, the conditions now are essentially the same as the previous grow. But this time, as soon as they developed, the leaves have tended to curl upward along their long axis and display a pale, metallic luster. The plants are putting on weight okay, but I want to maximize their genetic potential and something is not right.

Early this week I took steps to treat it as a general lack of nutrients (thinking the CO2 enhanced growth might require more than normal) and added a TBSP blood meal to the medium and bumped up the TVega 50% for one feeding. Still pale and curled...

Does anyone recognize this?

Thanks!

 

[Fuzzy Duck]

The edges of your leafs are curling upwards big time, my first first instinct would be Heat Stress.

The 2nd pic shows signs of leaf discolouration/yellowing on some of the tips, only a few but could be signs of a defeciency on the horizon leading to a Mg problem.

 

[Fuzzy Duck]

Which Canna growing medium are you using ?

I'm only aware of a coco mix !

 

[jfred]

Thanks for responding. Mr Duck.

I'm growing in the last of my Canna BioTerra Plus. It's a soilless, organic peat mix that was recently blocked from import because of a potential (never realized) beetle threat. I love it...great moisture retention, firm and supportive but airy enough not to suffocate the roots.

About the heat stress idea -- yeah that's what it looks like but, as I said, I'm at 80F which is surely not too hot, especially with extra CO2. Is it possible the light is too close?? I have it 12 to 15 inches above the tops, and with the air-cooling keeps it cool -- I can touch the hood or lens. I don't think it's heat per se. Too much LIGHT??

Last grow I had the damn thing right down on top of them 24/7 and they just sucked up the light. So I don't know...

 

[Fuzzy Duck]

I don't think the light is to close either & as you mentioned the temperature is fine.

Its was this little extract of info which made me think of Mg def...Margins of the leaves are turned up, and the tips may be twisted. Leaves are yellowing (and may turn brown), but the veins remain somewhat green - its does not even appear to be a text book classic symptom... Yet !

Keep an eye on that discolouration tho - sorry i could not help any futher, some thing may spring to mind later.

 

[BigDog]

Maybe try giving them some Epsom salts the next feeding, but not a lot! 1/4tsp per gallon, pre dissolved before you add it to the nute solution might help them quite a bit.

 

[jfred]

Thanks. Yeah, I think it is a Mg deficiency, although I don't really understand how it developed using a nute package like I am...?

But, looking at the symptoms and eliminating other possibilities (heat or water stress) I did start 2 days ago introducing a little MgSO4 into the process, first as a leaf spray then added to nutrients.

BigDog, thanks for the info on strength of the mix. Is that your "guess" at it or is that a "recommended" concentration?

I'll keep you posted on results.

 

[BigDog]

I've seen the 1/4 tsp rate posted on here many times, and it works for me. I found I jjust needed to feed it twice and the def was taken care of.

 

[jfred]

Right. Thanks for the info on how long to continue.

As I mentioned, I started misting the leaves with a dilute MgSO4 solution two days ago and added it to nutes yesterday, so I'm going to hold off and wait for results. Actually I think results are already showing -- there is still curl (which may not go away on leaves that already have it?) but that pale metallic pallor has gone and that pale-leaf-green-vein look is disappearing as color moves out into the leaves.

The 5 most recent photos (dated 2/11/12) are from this morning.

- 420 Magazine Photo Gallery

Let me add that before I began the Mg supplement I checked soil pH to be sure it wasn't off and interfering with nutrient uptake. If you know, please check my method on this, as it was a first for me: Poured a quart of 7.0 water thru one pot and collected the 2 cups that ran out the bottom. Excess measured 6.8. Is that a reliable method, ya think?

Edit: One last query -- this is my 2nd indoor grow and the first w Jack Herer. Four of my 5 large plants are from 12 to 15 inches tall -- one was stunted and is about half that and I'm raising 2 seedlings for a friend -- Anyway, any thoughts on when to change over to 12/12?

On the previous grow I changed over at 18 inches and had 3 ft plants to deal with by the end, although as I said) I took 6 oz off each plant. So, any thoughts or guidelines on when to flower Jack?

 

[Fuzzy Duck]

I'm pleased to hear ya getting some where with the defeciency stuff, Fuzzy had a gut feeling about Mg... & that leaf curling stuff should sort it self out in due time - give it several days or so.


I don't test my own run off tho, so i can not possible comment on that stuff ?


Mmmm well plant height 'n' stuff, 5 to 8 nodes or 12 to 18 inchs is good enough for 12/12 flowering regime.

• Indica strains will double/stretch in height through the flowering phase.
• Sativa strains will triple/stretch in height through the flowering phase.

Give or take a few inchs, don't ask about hybrids tho... this may varie a lil depending on indica/sativa dominate genetics !

 

[KeepItSimple]

hi jfred

i have no experience with adding co2 to a grow so i cnt really throw in my 2 cents but to b honest lookin at ur leaves they maybe suffering humidity stress as leaves curl to hold onto water they dont look to yellow plus i think u wud expect more uniform yellowing from older growth as well i read ur rh and temp readings where about have u got the monitor is it in direct light it cud b giving u a false reading

 

[jfred]

I think the Simplest thing I did to enhance growth, both in veg and flowering, was to add a CO2 set-up.

As far as humidity, my Grow Bible says 75F is ideal, but up to 90F with the CO2 at 1500ppm (as compared to 300ppm ambient atmosphere). I'm running 78 - 82F and keeping the RH right around 50%. I don't THINK that's too dry, is it?

 

[KeepItSimple]

no 50% is optimal range for flowering was just wondering if uve got ur rh meter in direct sunlight it cud b giving a false reading just read the rest of ur 1st thread to see u use exactly the same soil and feed as me just another thing do u ph adjust ur nutrient solution before u feed because u shudnt b that can be causing u nutrient lockout

 

[jfred]

What!? Wait a minute...hell yes I buffer EVERYTHING that goes into that grow medium to 5.5- 6.5. Is that not what you're supposed to do??

When I mix Terra Vega as recommended (in RO purified water with pH 8.0) the pH drops to about 3.5. Are you saying that I should just pour than on?

Oh, and the temp/rm meter is over on the back side of the fan. The room is light-tight, so no direct rays.

 

[KeepItSimple]

What!? Wait a minute...hell yes I buffer EVERYTHING that goes into that grow medium to 5.5- 6.5. Is that not what you're supposed to do??

When I mix Terra Vega as recommended (in RO purified water with pH 8.0) the pH drops to about 3.5. Are you saying that I should just pour than on?

Oh, and the temp/rm meter is over on the back side of the fan. The room is light-tight, so no direct rays.

yea i grow in canna terra professional plus so wen i make my nutrient solution i just fill up my bucket with water and leave to stand for a day or 2 to declorinate then add the nutrients u want then add to the soil canna terra soil comes ph stable already and will last a crop cycle read my thread on adjusting nutrient ph in soil damaging your plants!! its in the indoor soil cultivation forum by adding hydroponic ph up its probably causing nutrient lockout

 

[jfred]

...read my thread on adjusting nutrient ph in soil damaging your plants!! its in the indoor soil cultivation forum by adding hydroponic ph up its probably causing nutrient lockout

Darn. I was having so much fun mixing and measuring my powders and potions that I over-did it, didn't I? Hate it when that happens.

And see, that was one of the reasons I chose that "soil"...the very thing you're talking about, I remember reading in the literature. Thanks for the info in that other thread.

Okay, so (if you'll be so kind) a couple additional Q's?

Do you think I should flush the soil to effect something of a "new start"? By this time it has plenty of nutes and some Epsom Salts in it. Or is it sufficient to just stop adding buffer when I feed? (Which btw was pH Up mostly, in my case.)

I'm ready to switch to 12/12 NOW (due to plant size) but would it be a mistake to do that before getting the plants balanced and healthier and more able to produce great flowers?

Also (related) I was planning to cut clones just before 12/12. My cloner arrives Tuesday (Wish me luck!) and the girls will have added a couple inches by then. So, I want to switch now but I don't want to clone pre-flowering cuttings. Can I go to 12/12 on Monday and cut clones on Wednesday without confusing my cuttings or making them work backward?

Many thanks.

 

[KeepItSimple]

Darn. I was having so much fun mixing and measuring my powders and potions that I over-did it, didn't I? Hate it when that happens.

And see, that was one of the reasons I chose that "soil"...the very thing you're talking about, I remember reading in the literature. Thanks for the info in that other thread.

Okay, so (if you'll be so kind) a couple additional Q's?

Do you think I should flush the soil to effect something of a "new start"? By this time it has plenty of nutes and some Epsom Salts in it. Or is it sufficient to just stop adding buffer when I feed? (Which btw was pH Up mostly, in my case.)

I'm ready to switch to 12/12 NOW (due to plant size) but would it be a mistake to do that before getting the plants balanced and healthier and more able to produce great flowers?

Also (related) I was planning to cut clones just before 12/12. My cloner arrives Tuesday (Wish me luck!) and the girls will have added a couple inches by then. So, I want to switch now but I don't want to clone pre-flowering cuttings. Can I go to 12/12 on Monday and cut clones on Wednesday without confusing my cuttings or making them work backward?

Many thanks.

yea just before i switch into flower i completly flush my media anyway as a general rule of thumb so its worked out good timing as a general rule by jorges cervantes he says to flush ur media with 3 times as much water as soil before flower so if u have a 10litre pot u want to run 30 litres through the soil but i find that personaly abit excessive especialy if uve got alot of plants and awkward to access water so 15 20 liters wud b enough then the next time start feeding nutes again also with canna terra i dont just drop the vega feed as soon as switch i build it up over the first 2 weeks so i wnt feed any flores base nutrient the first week of flower then half and half the second week by then ur plants shud have shown flowering sites and changed into flower my 3rd week is full flores base nute and no vega from then thats just a suggestion tho

on the cloning question it generally takes a couple of weeks to change into flowering so IMO 2 days wudnt make a big deal but i havent tried this but i honestly think u shud b ok but post a thread on it see what people come back with