Leaves getting yellowish/burned

Heya Highness! What is the pH of you water you are giving to the plants? Looks like it is lacking a little in Mg, this causes yellowing of the outer edges and as it gets worse looks more like a burn/rust. I see you're growing in soil, pH should be between 6-7 and can be measured with pH strips or a pH meter. If you are out of this range you can use pH up/down solution to fix it. If your pH is spot on I would supplement with a little calmag. I see the nutrient line you are using doesn't have calcium in it and just a little magnesium. As well as the soil mix you are using is pretty basic and doesn't offer much nutrients as well. In my opinion when I did soil I loved the basic mixes because you know exactly what nutrients the plants are getting. When using peat mixes calcium and magnesium were always the first deficiency I ran into. Goodluck and cheers!