Critical Auto Feminised First Outdoors

My first outdoor grow since many years, and the first grow in my current location. I got 3 "Critical Auto Fem" seeds from Blimburn Seeds as a freebie from Seedsman, only 1 of them germinated. I planted it in a little peat pot and kept it indoors for the first week because outside temperatures were still too low

Moved the plant outside into an Airpot 9l filled with Plagron Batmix that I first flushed

Getting decent sunshine hours but we still have very cold nights with cold northern winds

Entering week 5, we got a lot of rain recently and only little sunshine. The plant develops well but she is the only one that is a little yellowish