Transplanting.

it depends. if you want to keep them small just let them sit.

Hey Jibby Jack, indeed you have transplanted to late, assuming these are Autos ? Better next time start in the final pod. Good luck!

i saw the plants are already showing white pistils you should transplant immediately

yap, your little bit late but its probably still worth to transplant

I'd say yes you waited too long and they got root bound. When any leaves edges reach the diameter of the pot its time to pot up to the final container.

Hey JibbyJack! To be completely honest with you, yes, you have indeed waited a bit too long to repot. Here’s why the situation is urgent based on your photos: 1. The beginning of flowering It’s clear from your pictures that the plants have already started producing pistils (the little white hairs at the top). When a plant begins its flowering phase in a container as small as a cup, it risks becoming "dwarfed" because its roots send a signal to stop growing due to lack of space. 2. Rootbound Given the size of the above-ground part of your plants, the roots have most likely already colonized all the available space in the red cups. They must be starting to curl at the bottom of the pot (the phenomenon of root circling), which will significantly hinder nutrient absorption and the future development of the plant. 3. What you need to do immediately Repot now: Transfer them directly into their final pots to avoid a second repotting stress later on. Be very gentle: At this stage (beginning of flowering), even the slightest root stress can block the plant for several days, which would be disastrous for your final yield. Transition watering: After repotting, water with pH-adjusted water and possibly a bit of root stimulator to help them explore their new space. In summary: Your plants look visually healthy, but they are screaming for more space. If they are autoflowers, every day counts because their biological clock doesn’t stop. The sooner they are in a larger pot, the more they can stretch a bit before focusing solely on the flowers. I hope I could help you. Have a great day!