Brown Spots on Leaves, Curling, and Crispy. Please Help!!

[dlev45]

Everything was looking great until right around when I switched from veg (5 weeks) to flower. Right now I’m 11 days into flower. Many of the leaves started to show brown spots and blotches. As it progressed, the leaves would curl upward and become very crispy. For a few days, I was loosing a few leaves a day, which seemed like a lot to me.

Also, newer growth near the top of the plant has brighter green outer edges with normal coloring towards the middle of the leaf.

I tested the PH of runoff water and it was showing low, around 4.0 – 5.0. Since the leaves were looking pretty bad, I decided to flush the plant with 15 gallons of fresh PH’d water. After the flush, the brown spots have seemed to slow down but they are still slowly spreading so I know something is still wrong.

When I watered again recently the runoff PH was low again, even though PH’d water going in was between 6.0 to 7.0. I upped the PH in the water going in until runoff was in a good range.
Is there anything else I should be doing? I’ve read CalMag might be needed but not positive? Any feedback is greatly appreciated! This is my second grow and I’d hate to see the plant not make it all the way. Thanks.

Setup:
- Fox farm ocean forest soil in 5 gallon smart pot
- AK48 feminized strain
- 6 CFLs, 32 watts each. 12,600 total lumens.
- Water every 3-4 days, when the top of soil gets dry. Add Jack’s Classic Blossom Booster every other watering during flowering stage.

[Bikerstonrr]

I can't say for sure but it looks like a ph problem. Here is a site for diagnosing leaf problems. http://www.growweedeasy.com/cannabis-symptoms-pictures

[Xaliuz]

Yea those PH readings you state are kind of vague. If using PH drop testing kit you should be able to get abit more accurate results. Atleast pluss/minus 0.5

[Flockshot]

I am no plant doctor but it looks like a calcium shortage to me. I had it, and that is what they looked like.

[dlev45]

Thanks everyone. I'm using the General Hydroponics pH Control Kit and still getting used to taking accurate readings. Flockshot, what did you do to fix calcium shortage when you had it?

[Flockshot]

I gave more CalMag. I doubled it at first and then came back a little.
You may already have enough calcium in the root zone and now that you have a handle on your PH it can be taken up, but an extra shot of calmah can't hurt. My 2c

[NebulaHaze]

I agree the pH might be what's causing the yellow edges of the leaves, especially if you know the pH is coming out very low. It might be helpful to give nutrients at 7 pH until it starts coming out in the 6-7 range, as that will help raise the pH slowly over time. It's possible the low pH is also causing the spots (since Calcium is poorly absorbed at low pH ranges), but a great Cal-Mag supplement is never a bad idea!

[Newf]

I had a similar problem with a cheap pH "meter" I got from local nursery. Thought I was using pH 6 water and leaves started doing this. Found out pH was actually about 4. Everything got better in about a week after fixing. Damaged leaves never returned to normal but all plants survived and doing well

[Soilscience]

Did the problem begin shortly after you began using "Jack's"?

Might be some incompatibly between products causing lockout. I don't use these products, but I noticed that the Jack's was a bloom booster and it began shortly after switching to flowering.

[dlev45]

Thanks, I'll work on giving water at 7 to bring up the pH at the root zone. Just ordered cal mag and will give that a try as well.

The problem actually started before giving any Jacks. I read FFOF has enough in it to be good for 4-6 weeks without adding anything else, just water. My plan was to veg for 6 weeks then switch, but since the leaf issues were showing up, I decided to switch to flower early (week 5) and then start with the Jacks as it was assumed nutrients in the soil have been used up.

[bubbadog]

Go to the Grow weed easy site, and go to symptom checker Id marijuana plant problems. good info

[dlev45]

Just an update, I've been adding calmag to the water and then pH to 7.0 when watering. Runoff is looking somewhat better, now around 6.0 to 6.5. The last watering was two days ago. However, the spots seem to still be spreading higher and higher up the plant and a lot of the stems are still really purple. See updated photos.

I have also been loosing leaves along the way these past days as many are going yellow and crinkling up.

Keep doing the same and stay with calmag and higher pH water? Any other thoughts? The spots spreading further up and up is super unsettling.

Could the roots be too wet from flushing and more watering? I've noticed these smartpots take quite a while to dry out at the bottom. Thanks!

[NebulaHaze]

Are you removing runoff after watering so the pot is never sitting in runoff water?

[DingusKhan]

Welcome. All that flushing may have corrected your pH, but stripped the nutrients out of your soil, and now they might need you to add nutrients early.

If you put a couple chopsticks under your smart pots, they will get a little air and dry out more quickly, and your roots won't sit in stew and rot. I found a silicone baking dish at the thrift store, it has a sort of washboard texture on the bottom. I have several chopsticks on the bottom, and the pot sitting on top of those. Or a few fistfuls of hydroton.

If I'm stoned and really tripping that I'm drowning my roots, I'll poke an air hose down into the coco. You could even poke one through the side near the bottom and aerate your roots that way. Dry that shit in minutes!

[DingusKhan]

Never mind. Sorry, I saw your using a fertilizer.

[Insight]

I find that this Egg Crate suspended ceiling tile is great for putting under smart pots. Keeps the bottom about 5/16" off the tray. One panel can make enough for at least 3, 5 gallon smart pots.

http://www.homedepot.com/p/Plaskolite-4-ft-x-2-ft-Suspended-Light-Ceiling-Panel-1199233A/202025149

[DingusKhan]

That looks cool.

[9fingerleafs]

That's gonna leave a scar. Leaves are not going to recover. Check the new growth for improvement. And give it some time.

[NebulaHaze]

Could it possibly be the Bloom Booster you're using isn't proving enough or the right kind/ratio of nutrients to replenish what the plant has used up? Is it possible to get Fox Farms nutrients and see if that helps, or even better, transplant to fresh soil? I looked up the Jacks and it seems like good stuff, but it seems like you're having nutrient deficiencies, which makes the nutrients suspect. If you live near a Home Depot or garden store, I know that a cactus or succulent nutrient will work okay in the flowering stage, and they're usually really cheap. It might be something to try.

Can you post a picture of the whole plant in the setup under the grow lights?

[dlev45]

I have it on an egg crate elevated above the drip tray with small foam blocks. I moved a small fan to blow on the bottom to help dry it & I don't let water sit in the tray after watering. Bottom still seems wet though. Pics of whole setup attached, it's a very small operation, in a wardrobe moving box! Lots of yellow leaves today.

How about Jack's all purpose 20-20-20? I have that on hand already. If not, I guess I'll have to try the Fox Farms trio or cactus nutrient...thanks everyone.

[NebulaHaze]

I personally wouldn't use the all purpose food, but it's up to you. Is the space getting lots of fresh air from outside the grow space? You mentioned you put a fan in there, was there one before? What is the humidity/temperature with lights on and off? It sounds like you're doing all the right things, and your setup looks nice.