The Grow Awards 2026 🏆

Back to Grow Questions

Black spots under leaves

DegenMJstarted grow question 3y ago

What are these black spots? I recently released some ladybugs in my grow room and saw them crawling on the plant this week, so is this possibly from them or from something else?

DegenMJ

Open

Leaves. Color - Black or grey

likes

Answer

GrowingTrannyanswered grow question 3y ago

High Bro, The cause for these black dots is a calcium deficiency. Instead of writing a long story about everything that could have caused it and the solutions possible I can better send you a link from the growweedeasy website with an article about everything you need to know about solving and preventing this deficiency. This article contains pictures that make it extra clear and you will see that the calcium deficiency is the problem because you can compare the poctures with your own plants. Here is the link: https://www.growweedeasy.com/cannabis-plant-problems/calcium-deficiency Enjou your grow!

1 like

Complain

Similar Grow Questions

Solved

Coco grow problem Hi Guys! I have issue in my grow. Girls are in 9th week from seed, 2nd week flowering. Coco substrat pH 5.8 EC 1.0-1.1 temp 23/24 humi 50%. Water EC 0.1 + calmag up to 0.2-0.3, Coco a/b up to above value 1.1-1.2/ph5,8. I believe that are deficiencies by too low ph for bloom stage

Leaves. Color - Black or grey

5y ago

1

2

Solved

Light distance and power I have lumatec Zeus pro 600w 2.9 Plan is to have it 50cm away 25% power 1st week veg 50% power rest of veg 75% power for 3 weeks of flower 100% power till the girls are finished In the 1st grow I’ve made mistake in the light management. Am I correct in my thinking this time?

Leaves. Color - Black or grey

4y ago

1

4

Solved

Otherland_Wildspice

Bugs/Spiders in Lower Canopy - Black spots on leaves I found some small bugs that were making Nets in the lower canopy. I removed the net all the leaves that were infected. Does anyone know what kind of bugs they are and how best to fight them?

Leaves. Color - Black or grey

Other. Bugs

Plant. Other

5y ago

1

1

Solved

Demande de diagnostic Bonjour, je suis actuellement en semaine 7, mon problème dure depuis la semaine 5 et je n'arrive pas à l'identifier... Quelqu'un à déjà eu un problème comme celui la?

Leaves. Color - Dark-brown

Leaves. Color - Black or grey

Feeding. Deficiences

4y ago

2

2

Solved

Black poison is starting to show her colors.What can i do to speed up or enhance this process.See photos.This is a outdoor grow .

Leaves. Color - Black or grey

5y ago

1

Solved

My dwarves are sick, issue with leaves Issues with my dwarves leaves, can you help me to identify them ?

Leaves. Color - Black or grey

4y ago

4

10

Solved

Yellow leaves with grey/dark outline I have some yellow leaves with grey/dark outline. Do you know the cause? Could be the humidity level too low? or K deficiency?! I'm not so sure about the last one. Help me guys please.

Leaves. Color - Yellow

Leaves. Color - Black or grey

5y ago

2

3

Solved

Problem with plants in the 3rd week of vegetation.I'm posting again because I accidentally marked it as resolved. I was using BioBizz CalMag from the beginning, but when I switched to Advanced Nutrients, I stopped because Ph Perfect Sensi Coco Grow A and B already contain CalMag.

Leaves. Curl up

Leaves. Curl down

Leaves. Color - Black or grey

1y ago

1

2

Solved

Old leaves , black spot Hello , today i cutted some leaves lowest who were yellow , on the plants. these leaves do not have much light. but i found some black spots and i don't know if it's lack of sun and simply died ? Can i just cut them ? What do you think about that ? Thanks

Leaves. Color - Black or grey

5y ago

1

2

Solved

Nutrient Burn, Leaf Septoria, Nutrient Deficiency? Or something else?I have been having issues with the Purple Haze. I've tried adjusting the Temperatures, adding additional Cal-Mag, changing lumen intensity etc. I believe this may be nutrient burn? Added an old image of leaf before mainlining, the plant is 1 week old after mainlining was done.

Leaves. Color - Yellow

Leaves. Color - Black or grey

Roots. Too few

5y ago

3

3

Solved

Still cant figure out what's going on with this plant. EC was over 2 for a couple of days but has since been taken care of, last reading was .83.Is this a deficiency or some other kind of issue? Some have suggested a p or k deficiency, but I feed Jack's 20-10-20 peat-lite so I would be very surprised if it was a P problem, and the problem seems to be all over the leaves, but a lot of them start from the base of the leaf.

Leaves. Color - Black or grey

Other. Mold

5y ago

3

Solved

Leaves turning funny Hello can anybody please tell me what this is and the cause plese for the leaves to be discoloured and dying ogf

Leaves. Color - Black or grey

2y ago

1

1

Solved

Blackening leaves on 2 week old seedling.Any ideas what has caused the blackening on the leaves? More effects of the overwatering? Hope it's not a lost cause but I'm losing hope.

Leaves. Color - Black or grey

6y ago

2

1

Solved

greyish leaftips and dieing branches after topping the highest branches died after topping. It looks to me like they had the same symptoms like some new upper branches are developing now. It looks very dark & feels soft Temps were 17-19°C & Humidity was 90%+ Water should be PH5.9, think ph reader might be wrong and ph is too low?

Leaves. Color - Black or grey

1y ago

1

1

Solved

Please see the 2 photos marked in the diary. Is this a classic PK burn? Did a feed with no MegaCrop, no cal-mag, just PK boost at diluted dosage. The coppering and yellowing has come sudden. Leaves are crispy where burnt. I hear its easy to burn with PK boost. Did I do that?

Leaves. Color - Black or grey

6y ago

5

2

Solved

dark discolouration developing in flowering wk 3 howdy growbuds, noticing the pictured discolouration. hope someone w more experience/knowledge might recognise what's happening to my gals before it develops. advice/opinions welcome on if maybe nut burn/def, temp or ??? a heap more detail in entries to help diagnose. cheerz 🙏

Leaves. Color - Dark-brown

Leaves. Color - Black or grey

Feeding. Deficiences

5y ago

2

4

Solved

Organic peat control I think my plant is being eaten but gnats and it looks like nutrient damage on it but I haven’t given ANY nutrients to it. What should I do? Can you diagnose my plant? Any remedies? I heard cayenne pepper can be used for a pesticide is there other things? Does Neem oil work well?

Leaves. Tips - Burnt

Leaves. Color - Yellow

Leaves. Color - Black or grey

5y ago

9

8

Solved

Leaves burn Hi! Is this nutes burn? Damage is on the upper/middle part of the canopy on very few leaves, but many more have black tips. I’m puzzled because during veg I was feeding the plant higher ppm than now and never had a problem!

Leaves. Edges burnt

Leaves. Tips - Burnt

Leaves. Color - Black or grey

5y ago

2

Solved

What Deficiency?What deficiency does this plant have? I have 15 plants inside this tent, all get the same nutes, all look great but only this one has these grey marks on the lower leaves

Leaves. Color - Black or grey

5y ago

1

3

Solved

what is this?1 plant has grey interveinal leaf spots and grey wilted edges. never seen this before. its only on top of the plant. my temps dropped to 17°C last night. light intensity is about 500ppfd. im guessing that it is a ph issue or overfeeding the other 2 plants are fine

Leaves. Twisted

Leaves. Color - Black or grey

21d ago

4

7