Newbie. Think my plants sick :(

has anything been sprayed on these plants?

Your plants are hungry. If you do not water enough and ANY of your nutrients are granular or pelletized then they are not getting these nutrients. Your plants need N and Calcium/magnesium for starters. Too much nutrients building up around the roots from under watering leads to leaf damage like burn. Your plants are clawing from undernourishment. If it was the opposite they would be yellowing and sizzled up at the tips.

Sooo this is where were at.. changed plant food to liquid.. fed them


First girl... dying I think..



Second girl.. now a lot more yellow than before.


Third girl that I'm not worried about for scale

I would check the ph.

Are these all the same strain? I see many new growers starting off with a multi-strain grow and I would discourage that until you have some experience. I prefer to grow a strain repeatedly until I know it well but that's a personal thing. Always check Ph first before you do anything else. Once you establish what the Ph is here's a simple a chart that will tell you what range different nutrients are best absorbed at. This will help you to relate different nutrients to their toxicity/deficiency effect, it's a learning process. Many times a deficiency and a toxicity problem will look so similar it will take experience to resolve the issue and there's only one way to get that. I've lost many, many girls over the years, it's part of the process. Keep a journal so you can spot a screw up. You can get ten different opinions from ten different people who know what they're talking about and end up completely confused. Search cannabis nutrient problems and click images. Don't try more than one solution at a time. It's better if you screw up now so you will know later. You have to be able to take a hit or you'll end up quitting. In my opinion this is the best advice because you'll learn rather than mimic something and not understand. I would use a basic three part nutrient to start with, you'll have more control and time release are hard to flush. All your problems seem to be in new growth...
Just my opinion