Space Cookies Balcony Grow

I don't think this is N or P deficiency. Maybe early signs of Ca or possibly Mg. It will use up more Ca then it will Mg. Could try a CaMg supplement with available Ca and Mg, Calcium Oxide and Magnesium Oxide thats in your feed are not readily available and don't breakdown all that well. So adding in a liquid form could help. You can make a Ca supplement via eggshells and any acid. or just by one. Mg is easy from epsom salts. You can also test your mediums PH by using a slurry test if you want. or measuring some of its runoff. If its aorund 8PH it needs to be lowered a bit. Good Luck!