How much of each fert did you use? How often do you water? Also symptoms sound like what a few of my plants went through damping off fungus all leaves died and fell off or just dropped off and the top of the stem wilted. My only hope was sprinkle with cinnamon and let them dry out also the worse affected repotted with dry soil to wick away the soaked soil.

Also the mix of lime and salt could have a negative impact not sure as I use one fert at a time like Epsom salt then next week or two use fish fert then what ever else I have. I would say the extra Mag from Epsom salt if your soil was already rich with it could cause problems also. IMO if the plants look healthy don't super nute them with over fertlilization, also Epsom salt has it's place but don't see the need to use it unless necessary to correct Mag def.

Mark

Habajolokia is correct. I am assuming your plants are only about a month old and damping off or just shock from a massive or incorrect application of fertilizers and nutrients.
That being said, if you are still hoping to save the plants, I suggest you transplant them immediately into fresh soil with just a light application of a general fertilizer. Give them another week or two and if they don't start improving, then it is time to dump them. If they do start to come back, you will likely see new shoots pop out from your "sticks".

But, if you have only invested a month on these guys, it might be better just to start over and replant your seeds and don't make the same mistakes again.
Bruce

Do you know how wet your soil actually is? The plants used a LOT more water in the summer. If you haven't moderating your watering scheme, you might have caused root rot or other nastiness down there. Do you have a moisture gauge? Or you could use the dowel method to check.

Treatment right now would be to let them dry out severely, then water moderately. But it might not be worth it.

I believe an Earthbox is a self watering container. And if they were beautiful and bountiful in August, I doubt damping off is an issue..that's generally seedlings.

The way I see it, you could repot them (remove all the old medium, and replace with fresh) or possibly flush the crap out of them to try and dissolve and wash out all the extras you added. Pretty much what you said you were trying to do by not using the tube to water...but, get serious about it. Slowly flood the thing until 2-3X the volume of the container has passed through. Then, let it dry out a bit and go back to your normal SWC practices. If you flush them, you may need to add back the strips of granular fertilizer if Earthboxes use them. If the strips are still intact (again, assuming Earthboxes use them) you probably didn't flush well enough.

Thanks everyone for your replies!

Mark- they are in earthboxes, so it's hard to overwater (thankfully) but I am very careful not to overwater them regardless! What would you suggest I fertilize them with?

Bruce- they are actually about 5 months old- planted in July originally, so a lot of love had gone into them.. actually got a very good harvest from all of them until I started trying to "fertilize" them..

DMF- no I dont believe it's root rot, they survived to monsoons of summer, and now I'm pretty careful to let them dry out before watering, and again, they are in earthboxes so it's pretty hard to overwater.

tsheets- I like the flooding idea, but the cool weather makes me wonder if it's even worth it or if they'll survive!

thank you everyone- they are limping along, no better or worse.. I'm thinking it's time to just pull them all and start new next summer.

how long have your peppers lasted in containers? just one season or years? thanks!!