They don't look totally bad.
It's probably soil, water and light -- haha, which doesn't help, huh?

Some look like they are getting lanky (etiolated) and the soil looks like I'd expect MG to look.
Depending on when you're able to put them outside in full sun, if it's going to be longer than a week from now, I'd probably repot into at LEAST a MG+Perlite (60:40 ratio?) for now. There we so many soil posts in the container forum that would probably be even better but assuming you're looking for the easiest solution -- I would think that's it. And then get them into more light immediately. I don't use indoor lights but based on what I have read, they have to be REALLY close to the seedlings, and given the height of your other seedlings shown in the photo, I suspect you can't get them close enough to these peppers without crushing into the larger ones?

I'm curious why you used a different soil for only the Jalapeños?

The plants need to be repotted they are already too large for the containers they are in. Also what type of MG did you use? It looks like Organic choice which contain hardwood that leeches nitrogen from your soil and the slow release nitrogen from chicken manure in it, can't compete. Also as stated by Sugi_C it would be best to add perlite to the mix this allows oxygen to the roots and keeps the soil from compacting. Also have you used any fertilizer?

Mark

Looks to me like they need a shot of fertilizer and some brighter light. With fluorescent lights the lights should be about an inch or two above the tops of the plants. I have my lights set up on chains so I can raise or lower them, but you can accomplish the same result by putting something under the pots so they are higher and closer to the lights.

As for water, I think it takes the blame far too often. Cold and wet will definitely hurt peppers, but it takes time, and the results are reversible. When I add water to my tray of peppers they often sit in standing water for a day or two, and I never let them dry out completely. When peppers start to grow on the plants letting the pots dry out then I think makes the peppers hotter, but when the plants are young I try to keep the growing conditions optimum, and that means water and fertilizer.

I agree. Some sunshine and ferts should perk them up considerably.

Okay, it sounds like next year I need to add perlite to my mix and be more consistant with my lights. I have used a blooms and roots fetilizer on them occasionally-about once a week. They still have had purpling leaves/ veins and a smaller, weaker appearance than my other peppers.

Sugi C. I used the same mix as the other peppers, I just got it wetter than i intended to when preparing it for transplanting.

For these plants, I will get them in the ground this weekend. I have full sun nearly all day. What should I use as a fertilizer in the garden? The only fert my parents ever use is grass clippings as a mulch. I don't have grass, so that is out. I would like something more to the purpose anyway. What would you all recommend? What sort of n-p-k should I look for?

Thank you all for your input! It is information I need for my next run at peppers. I did better this time than my trial run over the winter. I killed all my seedlings before they got to this size :(

Lynn

They look a bit overwatered too judging by the color. Could be the lighting but I would be cautious.