What your seeing is nutrient burn. If you must use a Monsanto product, you need to start in a starting/ seedling mix. The nute content is much more mild. I have a hard time chucking any plant that's above ground, so I'd probably try and nurse her thru. Plain water ph'd, no feeding. She might stunt, or she may grow thru it. I personally don't pull any leaf that isn't diseased, any photosynthesis at all is beneficial in getting her bigger. If she'll grow, she'll get to a size to were the nutes can be used.
Try to get some air moving directly on the plant without blowing it over. It will thicken up quick with good air movement. Also having your lights the proper distance. They'll get nice and woody. Miracle Grow has time released nutrients and is high in nitrogen so it will veg very nicely for your plants. But be ready to supplement cal/mag and PK. Miracle Grow should be avoided but regardless of what is said it has proven great results by those who chose to use it with proper TLC.