Salvageable? Or pull?

Whether or not you try to save them or pull them is going to be your decision here.... but if you want to try to save them organically, use some Langbeinite ... with an NPK of 0-0-22, it will get that K to them! Normally, when growing in soil, I use it as a top-dress (1 tablespoon once a month) throughout the grow as it is difficult to dissolve...but it IS possible to dissolve it - just needs to be ground up to a fine powder and then bubbled in water for 24 hours (I'll give a link at the bottom here)... Personally, I'd put the effort into it because this looks like it would be a great grow and there IS a lot of life left in those plants.... it's a weed, after all, and it doesn't particularly want to just give up the ghost when something goes wrong. Here's the link I promised... at the very bottom, it will tell you how to make it more quickly available to your grow in a nutrient tea: https://www.organicgardeningsolutions.com.au/products/langbeinite Good luck!