Yellow leaves

Hi,

I have a small Lowryder growing indoors in soil.
5th week since planting the seed, watering ~2-3 times a week

The plant have started to get yellow leaves, especially the top leaves.

Picture - zSHARE - img_2341.jpg

Any ideas on what could cause this?

Thanks in advance

you might refer to Cannabis Nutrient and Deficiency Table if you have not already