Ro0k
Member
Hi folks,
So I'm working on my second grow, and today I came home and looked in my tent and saw this:
That's... not good.
Setup:
So, I consulted my handy dandy Rosenthal book. There's a whole section on nutrient deficiencies with pictures right alongside.
My first thought was the usual suspect: nitrogen deficiency. But this is a red herring, since my nutes have plenty of nitrogen, and lots of research has told me it's usually something else. Most importantly, the bottom leaves seem to be okay. My next thought was something to do with the coco coir itself. I know that the canna coco line doesn't have a lot of calcium or magnesium in the mix, since they expect you to get it out of your water pipes. So I pulled up the section on calcium and had a read.
It could be that. But the necrosis is more uniform and not splotchy. The dead stuff seems to be starting at the edges and works its way in. And there's no yellow or purple color on the new shoots. So it's a possibility, but I wanted to dig further, so I hit up the Magnesium section.
That's not happening. The dying stuff is all on the top of the canopy, but the symptoms seem similar. Then I read this:
That sure looks purple to me!
I thought it was a characteristic of the strain, and I'd noticed it before, but didn't put two-and-two together until I saw the dying stuff.
As a last check, I double-checked my cal-mag dosage. Turns out I've been using the 'seedling' dose, like a dummy. So I whipped up a batch of nutrients, added the big-boy dose of cal-mag, and I'll see where I stand in a few days.
I tell you, folks, even if I'm wrong about this, I cannot recommend Rosenthal's book enough. It is a one-stop-shop for all your gardening and plant needs. If you do nothing else, buy this book.
I would, however, appreciate a second (or fifth or eighth) opinion. You reckon I've got this diagnosed properly?
So I'm working on my second grow, and today I came home and looked in my tent and saw this:
That's... not good.
Setup:
- 315w 3200k LEC sitting ~20" off the canopy (in-line with what the recommendation is)
- 4 Dutch Passion Blueberry fem seeds (because I'm apparently a masochist)
- 3 gallon smartpots
- Cana coco coir
- Canna coco nutrient schedule (light feeding)
- No drain table, so I vacuum up the runoff
- An every-other-day watering schedule, alternating nutrients and plain water to prevent salt build-up and hopefully prevent lockout.
- I flipped to 12/12 on Oct 14th, so I'm in week 3.5 of flower (almost half-way there)
- Temps have touched 32C a couple of times, but usually sit around 27C, with a low of 18-20C overnight
- Runoff is ~720 ppm, so it's not nutrient burn.
- My nute schedule says it should be roughly 900 ppm at this point, so it's more-or-less bang-on as far as I can tell. Better to have too little than too much, according to the farmer side of my family.
- Ph of the runoff is a bit high at 6.6, but I can't trust my pen, since I'm using a shitty ph pen which was allowed to dry out and hasn't been calibrated since May.
- That's the next thing I need to fix. But since I'm running coco, and my first grow the ph was in balance, and I haven't changed anything, I'm going to go ahead and discount that for now, until I can get the pen calibrated and know for sure.
- There was a half-hour power outage at some point in the last 3 days, which I wasn't home and/or was asleep for. I know, because I re-set my timers on Sunday for DST. I was worried that would stress the plant, but since it's already in flower, I'm hoping it didn't do too much damage.
So, I consulted my handy dandy Rosenthal book. There's a whole section on nutrient deficiencies with pictures right alongside.
My first thought was the usual suspect: nitrogen deficiency. But this is a red herring, since my nutes have plenty of nitrogen, and lots of research has told me it's usually something else. Most importantly, the bottom leaves seem to be okay. My next thought was something to do with the coco coir itself. I know that the canna coco line doesn't have a lot of calcium or magnesium in the mix, since they expect you to get it out of your water pipes. So I pulled up the section on calcium and had a read.
"Large necrotic blotches of tan, dried tissue appear mostly on new growth but also on other plant parts along leaf edges. Young shoots crinkle and get a yellow or purple color... Necrosis appears along the lateral leaf margins."
It could be that. But the necrosis is more uniform and not splotchy. The dead stuff seems to be starting at the edges and works its way in. And there's no yellow or purple color on the new shoots. So it's a possibility, but I wanted to dig further, so I hit up the Magnesium section.
"The deficiency starts in the lower leaves. The veins remain green while the rest of the leaf turns yellow, exhibiting chlorosis. The leaves eventually curl up, then die...."
That seems more like what I'm seeing, but then I read this part:
"As the deficiency continues it moves from lower leaves to the middle to upper half."
That's not happening. The dying stuff is all on the top of the canopy, but the symptoms seem similar. Then I read this:
"The deficiency is quite apparent in the upper leaves. At the same time, the stems and petioles turn purple."
Boom:
That sure looks purple to me!
I thought it was a characteristic of the strain, and I'd noticed it before, but didn't put two-and-two together until I saw the dying stuff.
As a last check, I double-checked my cal-mag dosage. Turns out I've been using the 'seedling' dose, like a dummy. So I whipped up a batch of nutrients, added the big-boy dose of cal-mag, and I'll see where I stand in a few days.
I tell you, folks, even if I'm wrong about this, I cannot recommend Rosenthal's book enough. It is a one-stop-shop for all your gardening and plant needs. If you do nothing else, buy this book.
I would, however, appreciate a second (or fifth or eighth) opinion. You reckon I've got this diagnosed properly?
