This is my first year trying to grow plants from seeds and I've been having a little bit of trouble the last week or two. I planted tomatoes, bell peppers and basil. The tomatoes were planted about 2 weeks before the bell peppers and they have since taken off fairly well. The bell peppers took about 5 weeks to finally poke above the dirt and for the past two weeks or so they looked like they were doing fine until the last 3-4 days. Since then some of them started falling over and shriveling up, others have leaves curling (both up and down), and some look just fine.
Here are pictures: https://imgur.com/a/7J6yn
The first picture is the group of seedlings that seem to be doing the best. The next 4 pictures after that have examples of the curling or falling over I was talking about. The final two pictures are tomato plants (both roma and 4th of july varieties).
I live in NH, which I believe is zone 5. I planted 3 seeds per cell about 1/4" below the soil level. I've been watering the seedlings twice a day with a spray bottle when the soil dries out. I usually give about 3-4 "sprays" per cell. All the trays of seeds are sitting on a window that gets a massive amount of sun during the day (usually from 9-10am to 6-7pm the seed trays are covered in sunlight and the windowsill is very warm). The house stays right around 70 during the day and night.
I've done a bunch of research before posting this and found out that I definitely didn't use the correct soil to start the seeds. I think I ended up using a regular garden soil which apparently is a big no-no Could that be the culprit?
I'm just a little confused how the tomato plants are doing so well but the bell peppers seem to be struggling so badly as they were both done the exact same way. Is there anything I can do to save the seedlings that seem to be struggling? The bell peppers look like they are just starting to sprout their first set of true leaves but it's almost like they have been stunted for the last 3-4 days.
Anyways, thanks a ton for the advice in advance!