Yellowing bottom leaves

@JreyBudz Hi mate the odd bottom leaf yellowing isn't anything to worry about it's just a natural dying off because it's unable to get adequate light ec. However keeping your ph within the optimum range at all times is essential to allow uptake of nutrients . Good luck mate

It is quite normal when the lower leaves are shaded by the top ones, since they can no longer get light, they die.

More Nitrogen my friend ! you have written that the Temperatur is 10 ! this is too low, warm Temperatur helps the Plant to abosrb nutrients better and helps the Bakteria in the Soil to grow properly to feed the plant , your Plants are little bit small for week 4,cheak the temperatur and Humidity level ,keep us updating :D