Spots and Curling of leaves

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hi all,

im having a slight problemn with these spots and slight curling of leaves.

anybody and ideas?

ive been watering relatively sparingly. (they are in 5 gallon tubs and get a few litres every couple days)

the plants look healthy but some leaves, not all are affected with this problem.

english isnt my first language, sorry

i have read some things online but am a little confused.

if somebody could adivise id appreciate it.

have a great day]


this is couple of them.

they are 2 months old.

time is 1820 in spain so normal they droop a little at this time but not the curling

What soil are you using (brand and type)? If you are feeding fertilizers I would back off the nitrogen product a bit. Dark, waxy leaves with burned tips are a symptom of nitrogen toxicity. It’s not too bad, but I would take steps to get it under control. Are you monitoring runoff PPM?


hi. im using a universal substrate type of soil. it is good quality, with perlite.

i have ordered a meter to measure ppm but it hasnt arrived yet.

somebody suggested potassium deficiency? what do you think?

i have been only feeding nutrients (liquid, potassium, nitrogoen and phosforus once a week as stated on the bottle)

perhaps i could up the dose?}}

you people are so helpful

thanks for alll of your advice

Brand and type, please. It matters.

Many soils are toxic for cannabis and can cause those dark, waxy leaves. These include Scott’s products, anything Miracle Grow makes, Vigoro soils, and any soil that says “Feeds for x months.”


hi there,

its this stuff. similar id say

Your English is great for not being your first language!

thanks :slight_smile: