I think SoOrBudGal has it right...you have a bit too many nutrients happening. It sounds like you're growing organic (so do I) and you really only need to add nutrients to organic soil once every 7-10 days and sometimes even less than that. So step 1 would be to get that part under control. Of course, if the manufacturer recommends something different than that, follow their instructions, they're way smarter than I am.
Next would be the lights. If they're autoflowers, feel free to keep them on 18/6. However, if they're photos, you have a miracle on your hands because photos only start flowering when the light schedule changes to 12/12. So step 2: if they're autos, keep them on 18/6. If they're photos, switch the light to 12/12 otherwise twisted tips are going to be the least of your problems. Also, is it Day 38 since sprouting or since flower? That could change advice as well but makes me think that it's autoflowering.
Finally, and most importantly, is to know that just like
SoOrbudgal mentioned, it's critical to remember that advice and 'rules' are only rules of thumb and the best results come from understanding the plant and thinking like the plant. What stage is it at? What metabolic processes are happening at what stage? What is the larger environment like (temp/humidity/ventilation/circulation/watering/lighting/nutrients/etc.)? Sure, you can ask a question and get 50 different very specific answers likely none of which will be perfect for your situation. But the better and more 'educational' answers are always: Get back to the basics and make sure that you understand them intimately. You've been growing for 3 years and you have more knowledge than you know. It's good that you're looking for advice, but trust yourself - you'll find that most often, you already either know the answer or have a hunch as to what you may have forgotten or done differently from your grows over the past 3 years. If you don't already, keep a grow journal. Make notes every day or two or three about how the plant is doing - how tall/wide is it? How has it reacted to different inputs (changing distance or intensity of lights, changing watering regimes, adding or reducing nutrients, etc)? How is the plant reacting to any 'corrections' you've made to prevent/stop a pest or problem? I go back to my grow journals all the time - like I said, I'm not so smart and I have a memory like a sieve so it's super helpful and helps make sure that I am continually learning and becoming more in tune with the plant as opposed to following a set of rules or a schedule that, although they feel like they're hard and fast, cannot possibly cover every situation or environment that a living thing like a plant might experience.
Good luck and keep us posted!
