Hey everyone. I’m trying to pinpoint a suspected deficiency I’m having with my grow of Wedding Cake. The girls are just starting week 4 of flower and the last few days some discolouring has showed up on the mature leaves. Seeing lots of rust coloured spots appearing. From what I’ve read it doesn’t sound like rust fungus but more like a cal/mag deficiency. Please see attached photos and give your thoughts. Any help would be much appreciated. I don’t want to just start dumping in more nutes and make the problem worse.
For more info I’m running Happy Frog soil in 3 gal pots. Plants have been in there since mid veg. I’ve been feeding during flower with the GH Flora series and following the simple drain to waste chart, as well as Cal/mag (5ml/Gal) and green planet Rezin (8ml/Gal). Using RO water Ph to 6-6.5. No signs of any bugs under leaves. I did have a Fungus gnat issue last month but treated with neem oil and havnt seen any since.
Good to see you back online, welcome back. Dont chuck more nutes at this problem, it could be nutrient burn or like you say more like a cal/mag deficiency. Perhaps start there with a simple solution and foliar spray. Maybe others have better advice @TheMadFlascher@PreyBird1@Slym3r
@hatebreed…I don’t believe that is nutrient related at all.
Let me ask you…do these spots begin as yellow and then a few days later, the center of the spot tends to turn reddish or brown?
Nutrient deficiencies will normally show with lighter leaf color or slow growth. Nutrient excesses (high EC) will usually show up as burning from the leaf tip progressing towards the stem OR necrotic lesions along the leaf margins.
What you have there going along the midribs looks to me an awful lot like Septoria Leaf Spot.
You can google the subject (there are lots of photos) and see if you find similar spots…FWIW
Chris, is this grower in SA…I only ask because our US Septoria looks a little different…obviously there are lots of Septoria subspecies but this one looks unique to me…
Well, it’s a fairly serious fungus …
I don’t think the neem oil thing is going to help you much!
My advice would be to contact local grow shops or garden shops for advice…I’m really not certain what’s readily available for you, but I’m guessing when you mention Septoria Leaf Spot, if they haven’t heard of it, you want to go somewhere else. Another possibility may be checking with some agricultural fertilizer/chemical dealers and they could tell you the most effective cure available to homeowners…Good Luck Bob
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.
another great suggestion. Thanks guys I knew this was the right place to ask. The Facebook suggestions have not been helping lol insert CalMag meme here
@hatebreed
Start a journal. Swing by every once in a while put up a post and show some pictures, show off what do you have going. We’d love to have you hang out with us.
Not really…
You are absolutely correct with WPM or rust, however a serious fungi infection like Septoria, Alternaria, Anthracnose, Pythium…do not respond to the ‘rub test’ unfortunately !
This often causes growers to revert back to nutrient issues where they waste time and money fighting the wrong issue…JMHO
Donk! That’s exactly what I did when I saw brown spots on one of my clones. Did the rub and didn’t see any orange on my fingers. Then I did exactly what you said, looked for nutrient issues. In my case, I guess I got lucky since it I found a drainage issue and once I fixed that the browning stopped completely.
But now I will know not to dismiss fungus so easily. Thanks for the info rflasch
