week old clones still have no roots whatsoever.

so a week after cloning, i checked the girls yesterday and they had absolutely no root system with them exception of 1 from the 13. i realized that the concrete floor was decently colder than the air surrounding so i put em on a platform. some of the plants also have some yellow spots on the leaves so a moved the lights a bit further from the plants as someone had told me to do. i also recut the clones cuz it looked like the guy who gave em to me didnt really cut anywhere aside from where he detached it from the plant. i was wondering if took care of em correctly. thanks in advance

cuts can take weeks too root.

I got different strains, and on some, I get roots in a week, and others 2 weeks, some three weeks, after that, i'll just throw them away.

If the cuts are stress, they can take sometime.If that's the case just start over?How they look?

well now that you recut them it will take longer and the yellowing is probably from using the stored nutes. you may end up with a problem there if plant runs out of stored food before roots grow. cuttings need very little light to root.

Do they have good contact with the medium? I use a heat mat.

Just wait longer. Some of them are stubborn bitches.