Do you have a solution to stop the growth of stems?

As your buddies are telling you, you have a significant lack of direct light, which is causing the stretching. My advice: - Transplant to tall pots of 2 or 3 liters. - Bury almost the entire stem when transplanting. Leave only two or three centimeters of stem above the substrate. - Give them light! Two options: 1 - If they are going outdoors and the ambient temperature does not exceed 25 degrees Celsius, take them out to the light while ALWAYS avoiding the central hours of the day (from 12 to 16). 2 - If you can't control this, get a basic 50w LED light (you can find them for 20 euros on sites like AliExpress) or get some growth CFL bulbs. Good luck and ask whatever you need!