Speckled leaves - what now?


I noticed some brown speckling appearing on the lower leaves of one one my plants this morning (my healthiest one until now :cold_sweat:), as well as some light specs on some upper leaves. Searching online for similar issues, I found spider mites, nutrient burn, and magnesium deficiency as some possible causes.

Can anyone help me narrow down the cause and fix?


The 4th photo (one from the bottom) favors the calmag deficiency. Im no means an expert do wait for other votes of confidence. But doesnt look like bugs imo. Have u been supplementing calmag in waterings?


I haven’t been supplementing with calmag specifically, just Biobizz nutrients mixed in tap water. My district’s annual water quality report notes about 0.6 mg/L of magnesium in the tap water, but I don’t know if that is an adequate amount for cannabis plants.


Me neither :joy::rofl::joy: wait for the pros regardless. Im still fairly green myself.


After more research, I suspect CalMag deficiency. We have very soft tap water here, low in both magnesium and calcium (and probably iron too). I’m going to try some Sensi CalMag Xtra and see if that helps, unless anybody else chimes in with different advice.


Im only on 4th grow but i do know cannabis Loves calcium & mag & potassium! My girls scream for more & think thats what shes foing.Think the calmag will fix her up if not fill out support ticket & lets see whats going on.


I’ve been adding calmag to my water since noticing this issue, but it almost looks like the older, larger leaves are getting more speckled:

Maybe it’s just the same leaves becoming more visible, as they grow taller and are easier for me to inspect, or that they’re in starker contrast to the newer leaves around the buds, which are a very dark green, without any speckling.

For folks with more experience, does this look like calcium or magnesium deficiency? Our tap water (and the BioBizz nutes I’ve been using) are very low in both, so it seems like a logical explanation. Odd that it would only affect one of three plants treated identically, though.


hmm, just noticed similar speckling on leaves of a birch tree in the yard, as well as some holes in the leaves on that tree and on a variety of other trees and bushes. Maybe I’ve got a bigger problem than just my MJ nutes… :thinking:


Im not so sure that looks like calcium deficiency. Have you looked for bugs?


Looked for them but haven’t seen any.


@Countryboyjvd1971, does this look like calcium deficiency to you? Im not sure.


Ot doesnt look like calcium to me my initial reaction was bugs also
@raustin and one of the leaves looks like something waas munching on it a good bug inspection may be wise

Other wise fill this out

COPY/PASTE the below list into your forum post.
Answer these simple questions the best you can.
If you do not know, or do not use something; Just say so = NA

  • Strain; Type, Bag seed, or NA
  • Soil in pots, Hydroponic, or Coco?
  • System type?
  • PH of runoff or solution in reservoir?
  • What is strength of nutrient mix? EC, or TDS
  • Indoor or Outdoor
  • Light system, size?
  • Temps; Day, Night
  • Humidity; Day, Night
  • Ventilation system; Yes, No, Size
  • AC, Humidifier, De-humidifier,
  • Co2; Yes, No

If you can, upload a picture of your plant. It helps the diagnosis, if needed.

Add anything else you feel would help us give you a most informed answer. Feel free to elaborate, but short, to the point questions and facts will help us help you :slight_smile:


  • Strain: Cheese Autoflower
  • Soil in pots: Biobizz Light
  • System type? ???
  • PH of runoff or solution in reservoir? Unknown
  • What is strength of nutrient mix? EC, or TDS: Unknown. Biobizz nutes diluted per instructions
  • Indoor or Outdoor: outdoor
  • Light system, size? Sunlight, ~ 5 hours direct, 8 hours indirect
  • Temps; Day, Night : 80s - 50s
  • Humidity; Day, Night: Anywhere from 30% to 100%
  • Ventilation system; Yes, No, Size: N/A
  • AC, Humidifier, De-humidifier: N/A
  • Co2; Yes, No; N/A


@Countryboyjvd1971 I filled out the questions as best I could in my reply above and posted a couple pictures of the plants. I also took a closer look and noticed some more small holes on leaves of the two plants that aren’t showing any of the speckling/discoloration. Here are pictures of those:

I still can’t see any bugs on or under the leaves, though. When one of plants got some bigger holes in them earlier in the grow, which I suspected were from slugs, I sprinkled some Sluggo around the base of the affected plant and also sprayed some Dr. Earth Final Stop Snail and Slug killer spray around the base of the all the plants a couple hours after each watering for a while. I sprinkled some Spinosad dust on the affected leaves too and didn’t notice any more holes for a while.

I’m still not sure what exactly is causing these holes though, so I’d appreciate any insight you have. What, if anything, should I be doing at this point to keep it from getting worse? I’m reluctant to get any insecticides, even “natural/organic” ones around the buds, as I really don’t want to be ingesting that stuff.



I had one bug chewing on all my plants last grow. Im indoor and luckily i was able to dispose of said bug. I definitely see chew marks and im with @PurpNGold74 i have seen the same thing in early grows at this stage and a more progressive stage and cal/mag was my answer. The diagnosing is a tough game, so many variables. Hope this helps One LoVe


This definitely looks like bugs. Keep a close eye out and maybe invest in food grade de. Its a white powdery substance that is a lovely preventative measure against many types of insects. Sorry i missd earlier. Didnt see and bite marks. But the last photos show something chewing. Look around daybreak/sunset. U may catch something. But ull need deterrence regardless


I had the same thing this past summer. It was spider Mites.