Plants leafs turning yellow with spots!!?

Hey guys got some plants growing outdoors in aus, in a park somewhere and I checked them today and last week, for some reason they have these yellow spots al over them, which seem to be killing the leafs..

Here we go

Anyone?

Help would be appreciated as it’s my only crop

I'm a noob too so don't take my word for it but I'm having a mild problem with mine as well. I get random green/ brown spots but that's because I'm lacking calcium. I watched a YouTube video earlier and the dudes looked like yours. His had a calcium and magnesium deficiency.