Before Taking out the plantlets, you should expose them at high intensity of light say more than 4000 lux for a  week or two and then in green house conditions followed by natural environment. I hope you will find some more success.

Will do this. may be it will helpful

As my experience,you should cover a plastic or glass jar on your plantlet at the begining days ,and you could try watering your cotton by MS leqiud. Hope it's helpful.