Always try to upload a clear picture of any issues you may have to allow the community to assist you.
Add anything else you feel would help us give you a most informed answer should be included. Feel free to elaborate, but short and to the point questions and facts will help us help you in a more efficient manner
You need a longer rest time you are at 20-4 drop it to 18-6 or 16-8 that’s what I like to use even if they’re autos I would drop them down to 12-12 they do most of there growing at night do you have a pic of the whole plant?
If you order the big bags of Jacks 321 the you will still need to buy some epson salt, but if you get one of the smaller kits they usually come with Epson Salt as one of the bags. It’s 3 parts A, 2 parts B, and 1 part ES.
Had a whole other post about which fert to use with my organic soil as I was going to use FF triple pack, but got sent looking for Jacks or Gaia Green as that’s seems to be what most people use with great success and I don’t want to have to flush my soil all the time.
Almost wrote “flush my soul”, but sadly I’m a ginger and KIA wouldn’t even sell me one…
Plant looks very hungry and deficient, go full strength on the Jacks (3.6/2.4/1.2) at every watering and it’ll come around pretty quick. Yeah don’t need calmag with Jacks 321, has plenty of calcium (part b - calcium nitrate) and magnesium (epsom salt) when used at full strength.