lights are too far away and/or not enough wattage. they are stretching for light and have stretched soo much they cant support they're own weight. read the stickies
And they look a little too dry. Adjust the light like was suggested and give them a shot of Vitamin B-1.
agree with the light being to far away,and them stretching for light,and now not being able to support them, maybe its time to consider a transplant,and bury just a wee bit deeper
once you fix the lighting issue there are a couple of things you can do to save your babies. 1. like warparty sed, repot a lil deeper, almost up to the bottom set of leaves or... 2. simply lst the stretched stalks down as long as you make sure to correct the problem one of these two methods should get you back on the right track