3 weeks growing auto seeds bottom leaves going yellow?

3 weeks growing auto seeds and bottom leaves going yellow and my il divalo starting to gain strange purple patches>

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What is the medium you are using...those girls need fed

im using multi purpose compost. do i need to change the soil?

use 30% perlite in your soil it helps your roots breath and get stronger and helps with drainage which it what you need by the looks of it there drowning

ya, perlite will help as well but they still need fed.

the cotledons which are the first 2 round leaves will yellow and drop off anyway its nothing to worry about. back off on the watering and let it dry out between waterings, a heat mat under your seedlings will help. also add a very light soloutin of feed on next watering but let it dry out and let the roots do some work.