When are plants mature enough to start the 12/12 cycle for flowering? Can you tell by height? Idk how old these are so im assuming they are about 3 weeks. Sorry about the slightly blurry cell phone pics.
Those plants are stretching too much. Move the light source closer or get a better light source. As stated, alternating nodes indicate the plant is ready for flowering. If those plants really are 3 weeks old from sprout, you have a long veg time ahead of you if you're expecting halfway decent results. At that rate, expect to start flowering in late June.
LOL,....literally.......that's some funny stuff. [Those aren't ready....] lol.....good stuff. I was expecting the same thing you were. A plant that obviously was ready to flower, but....might still be a lil too small to get any worthwhile yield. Those pics.....were funny. To answer your question with a question. What? Those plants look like they broke ground last week. You might need better light. Are you using incandescents? Do you have them near a somewhat sunny window. What's up?
you can technically break a seed from 12/12 and flower from the start but it order to make it worth your time in seeing a yield i would wait till the plants were about 12 inches and had some nodes before i flowered unless you were just checking the sex