They should do fine in the same starter mix.I also am a newbie at growing hot peppers.I growed some jalapenos from seeds and also some mixed hot seeds from walmart and didnt have any trouble at all.I actually took many of the peppers to work as I couldnt eat them all.They were super easy to grow and alot of fun,so much in fact that Im trying some more special ones this year.So I guess we will see,anyway good luck with your peppers.

What you did is full of risk that you will get the plants confused. some seeds are very slow to germinate. Better is to use new soil for the new seeds. if you want to use the old soil then plant something different like a tomato after peppers. That way when the plant comes up there will be no confusion.

What you did was poor discipline. It might work once but it will backfire on you in the future. Too much risk for too little reward.

potting soil is so cheap. you only need a penny worth to germinate the seed.

Pepper seeds should be started 2 weeks or more before tomato seeds. Lettuce seed is very fast. etc.

I mark each 6 pack with seeds. If I reuse a 6 pack then i leave the old marker in the pack and add the new marker. I can tell the difference if an old seed comes up. But in general it is not worth the risk. I will usually just give the first ones more time. Even an extra month at times to germinate. Then discard the soil.

You might be confused if these two peppers get mixed up but as soon as they show peppers on the plants you will know the difference. There is an enormous difference between a bell pepper and a jalapeno. but not until a pepper forms especially for someone new to growing from seeds. With a little experience you will probably be able to tell sooner. Some Jalapeno get purple on the stems more than a bell. The flowers should be different and the thickness of the stems should be thicker on the bell. the bell will probably grow a little more upright and possibly taller. the leaves on the bell will probably be larger.

But just relax for now and stay with what you have. Just try to be more disciplined in the future.

If the only concern is that I might be confused, then I am in great shape. As I said, EVERY seed I planted germinated, so there were no seeds left in that medium. I planted 9 seeds, and all 9 came up. I only need 4 in my garden, so I am in good shape.

I appreciate your advice, and if I had not had ALL of the seeds germinate, I wouldn't have done it. But, I figured that set-up was so good for my bells that I would just re-use it for the jalapenos.

Hopefully it will work out as well, but I have no concerns about being confused. There are no bell pepper seeds left to confuse me. :-)

I've done the same thing before if a seed is a no show(I'll pick the unsprouted seed out) or after I transplant the original seedling. As long as you didn't have any signs of mold or fungus on the medium, don't worry about it.
And "so what?" if you're not sure if your new seed turns out to be a jalapeno or a bell pepper...its no big deal unless your growing them to sell. There are always going to be mix-ups and surprises. Gardening is a constant learning experience. It was not a big risk and it was not poor discipline. Relax and ENJOY your gardening!

Thanks noinwi. There was no mold that I saw. I did moisten the added seed starting mix to the container with the chamomile tea solution, so I was feeling very confident that there was no damping off risk.

I also watered in the "pricked" seedlings with the chamomile tea solution, just to be safe.