dark spots and leaves curling upward

[MisterAvocado]

Recently some dark gray spots appeared on a few upper leaves of my 6-week old shishkaberry mother plant. By the next day (when attached picture was taken), the gray spots had turned brown on the affected leaves, and these leaves had yellowed and curled upward. Plant is 18-inch tall, got it as a clone. Growing in FFOF, 2# pot. I administered humtea and hygrozyme (soil drench) a couple days before this, doubt that it's related. Also, I may have over-watered slightly, a few days prior to this. New growth (since photo was taken) appears normal.

I don't usually add cal-mag, should I?

other info:
- Water: I use with carbon-filtered tap water, pH 6.5.
- Food: FloraNova Grow. PPM 600-800. feed-water-feed-water. no foliar feed yet.
- Lights: 3x1000w HPS. 4-feet above top of plants.
- Room: 70-75 degrees, 55% RH, 1400 PPM CO2.

thanks for any advice.

 

[Go Big]

Dont need CO2 on a mother plant, save it for those in flowering after week 2......... Good luck!! (This isnt the cause of your problem, just a suggestion based on your stats)

 

[Seamaiden]

I would try a foliar of MgSO4 (Epsom salt) @ 1/4tsp/gallon, see if that stops the progression. Otherwise, I'd give a foliar of Botanica's MaxSea for acid-loving plants and see what happens (again, stop progression).

If it were on lower leaves then I'd feel more certain, as that would indicate immobile element deficiency or uptake problem. Since it's not, I would use a foliar to see if I can nail it down a little better, as described above.

 

[MisterAvocado]

another photo

here is another photo showing the progression of an affected leaf. I think the new growth looks ok.

 

[MisterAvocado]

burn from lights maybe?

I'm starting to wonder if maybe this was caused by burn from lights.. due to its place in the room, this plant was getting hit with an assload of lumens.. I've moved it back to its old room, which has only a single 1000w MH.

 

[altitudefarmer]

It's not light burn unless the tops are fried worse than the bottom. Try the epsom foliar, as Seamaiden suggested. If that slows the damage, add cal/mag to you nutrient regimen. I've always thought FloraNova was mg deficient for cannabis. Is your runoff pH 6.5? Test that before you change anything with nutrients. I'd be willing to bet your FF is getting more acidic every time you feed. However, lockout or no, the foliar will help.

 

[supercharged]

i get the same thing bout 25days into flower, think its a magnesium def bro but as seamaiden says try foliar feed with sum epsom salts2sort the problem
hope everything turns out ok4u bro, peace out

 

[MisterAvocado]

more pics

Seamaiden et al.,
thank you for the diagnosis. I did the espom salt foliar feed yesterday per your instructions.

A correction from above: this is not a shiskaberry. It's actually a Mr. Nice Guy. Sorry about that.

I'm attaching some more pictures of this plant (taken right before yesterday's epsom salt foliar feed).

thanks again for all your help.
-ma

 

[MisterAvocado]

lockout?

Two days after the epsom foliar feed, I saw progression of the symptoms (maybe slower than before, not sure). So tonight I decided to flush.

Flushing with pH 6.5, PPM 100, the initial runoff was pH 4.7, PPM 1800. I flushed with 4 gals, and runoff eventually went to pH 6.3, 400 PPM.

Does this suggest that lockout was preventing Mag uptake? Should I continue with the epsom foliar feeds?

 

[Seamaiden]

Only if you see an improvement. Know that the damaged leaves won't come back (some folks expect that, can't remember how much growing you've done, so just sayin'), but that your goal is to stop progression of symptoms.

I am not well-versed in the hows of how all these minerals work together, but if magnesium is out of whack then calcium uptake can be borked, which can kludge up phosphorous uptake, which can mess up the magnesium uptake, which can... you see how circular it is?

I would continue with foliars of Epsom, or, if you have it on hand, I'd do a good Ca/Mg foliar.