What is this spotting problem?

I am growing hydroponicly and have this on my leafs. What can I do about this. Thanks

Uploading: CC832A06-F6EF-47CE-B35A-9B1601FE1EDE.jpeg…

looks like either Calcium or Magnesium deficiency…???

the more info u provide about your grow the better help u can get.!

I use RO water, ph 6.0, Fox Farms Dirty Dozen Hydro fertilizers, Air stone and recirculating pump, room temp 70-77 deg. F. , humidity 50-60%, led lighting 18-6.
Last week the plants looked like this at 3-4 weeks

This week

Where has your pH and PPM been running?

5.9-6.1 at around 1200ppm

Support Ticket would give others the info they need to help you best.




I already updated my original post to add all info.


Size of the grow room?, what type of LED (actual watts, brand?), Is your pH and ppm you listed from run off or what you added, strain of the plant? Air filter, fan? How far from that plants is your light. Where on the plant was the leaf in the picture from? How does the new growth look? Just tying to help.


1 Like

Strain; Type, Bag seed, or NA… Ilgm white widow and Granddaddy Purple

Soil in pots, Hydroponic, or Coco?.. Hydroponic

System type?.. DWC

PH of runoff or solution in reservoir?.. 6.2 at SIR
Water temp in bucket is 70-72F

What is strength of nutrient mix? EC, or TDS… 1035 tds

Indoor or Outdoor… indoor

Light system, size?.. Mars hydro Pro II 256 CREE 1200 watts. 24 inches from tops

Temps; Day, Night…,…,… 77F max day, 68F min night

Humidity; Day, Night… 50-60%

Ventilation system; Yes, No, Size… yes

AC, Humidifier, De-humidifier. … yes all

Co2; yes/no… No

Fox Farms hydro ferts and nutrients

Ten gallon container

Light. 18hours on 6 hours off

5x5 tent

The leaf spot started on the lower parts of the plants and quickly went to 70% of the plant.
I trimmed all the lower branches off and cut off all leafs affected.
If you read the whole thread, I have answered all or most of the support ticket questions.
I have four plants growing but only one got sick.


What are the temps in your res where your roots are?

1 Like

This makes all more complicated. Plant have now less chance to recovery/chance to survive.

Looks more calcium than magnesium.

I’ve only grown in soil, but isn’t the pH a bit high for hydro?

Is that leaf curled because you cut it off and it’s drying, or are there other leaves on the plant taco-ing like that?


A magnesium deficiency, as manganese deficincies are mostly characterized
by interveinal chlorosis which is a yellowing of the leaves between the
veins with the veins remaining green. The browning spots is called marginal
necrosis which is usually caused by a calcuim or magnesium deficiency.

A magnesium deficiency can be quickly resolved by watering with 1 tablespoon
Epsom salts/gallon of water. Until you can correct nutrient lockout, try foliar
feeding. That way the plants get all the nitrogen and Mg they need. The plants
can be foliar fed using ½ teaspoon/quart of Epsom salts (first powdered and
dissolved in some hot water). When mixing up soil, use 2 teaspoon dolomite lime
per gallon of soil.
If the starting water is above 200 ppm, that is pretty hard water, that will
lock out mg with all of the calcium in the water. Either add a 1/4 teaspoon per
gallon of epsom salts or lime (both will effectively reduce the lockout or invest
into a reverse osmosis water filter.
Mg can get locked-up by too much Ca, Cl or ammonium nitrogen. Don’t overdo Mg or
you’ll lock up other nutrients.

Calcium deficiencies are difficult to distinguish visually as excess calcium may
produce deficiencies in magnesium and potassium.

I use RO water and it comes out of the RO tap at 8.1pH and 060 ppm.

I will try the Eason salt treatment. Thanks for the great explanation.


1 Like

I was going to cut it down to prevent any spread to the rest but trimmed it.

70-72F degrees in the bucket.

I hope it works out for you. Please let me know if it does or not … ok

Thank you. I hope they do well too.
This is my first time growing hydroponically and so far I’ve learned so much.
The water here in Arizona varies so much as far as pH goes, it’s hard sometimes to keep on top of it. One day out of the well the ph is 5.5 and the next day it’s 11.5.
I have two electronic ph testers and two liquid ph test kits. Thought I was going bonkers trying to get readings but it was the water. I’m thinking of purchasing a pH auto dosing/monitoring unit and setting it for 5.9.
The bucket temp is stable at 70-72F so maintaining the pH with better equipment will or should help.

Thanks again for all the advice and I will keep everyone posted. Plus this forum is great. Lots of good info.