Caelian, I have one tabasco plant that has one curled leaf just like yours pictured above. My plant is in a 5-1-1 soil.

Hi Jifjifjif, thank you for the post. So many hours I have been looking for information about this problem by Googling but I cannot get much useful information. I have three plants have this problem.
Caelian

It looks a calcium deficiency to me, try some cal-mag+ in your nutrient solutions.

Here is a link that might be useful: youtube link to calcium deficriency

Tyle6, thank you for the link. I think so, it would be calcium deficiency. Today I gave fertilizer + super thrive and tomorrow I would like to spray Epsom salt.

Caelian

Epsom salts really only contain magnesium, unless the problem is calcium uptake lockout due to lack of mag. in the soil they wont really help. you could try washed and ground eggshells or ive heard of people using dissolved tums even.

eggshells won't break down fast enough to make a difference.

Agreed that it appears to be a calcium deficiency. Took me a bit to figure that out on my superhots as well last year but supplemented with Cal-Mag and they thrived. That's all I really needed to give them once in a while. I agree that eggshells won't break down fast enough and won't provide enough for superhots. Anyone know of a more "natural" supplement like boiling eggs in vinegar water, grinding shells and watering with that? I thought I had read about something similar.

Had this discussion last season.

My plants grew out of it without eggshells, tums or any other calcium supplements.

Just good old Tomato Tone and some patience.

Here is a link that might be useful: curled leaves

Thank you all for your suggestions, opinions and very informative links.

Caelian