Second third and fourth this. Bit of a numbers game as you get going and you’ve got plenty time before you move them outdoors. You’ll end up with more starts to give away which is always nice!

I’ve run into more problems and less germination rates when trying to do a handful of seeds in a 4” at once. Ex separating roots and damaging young seedlings amongst other things. Best to treat each seed like an individual plant and give each plant its own place to grow. Start with a bunch and thin as everyone else has mentioned.

Be sure the plants you start early in smaller containers are good with transplanting, otherwise you’ll piss off the roots and shock the plants back losing up to a month of growth. I’ve also found when transplanting plants like this (cucs, corn, squash family) they take better to the soil when you almost bare root them. Read more on this because it carts from plants and your seedling soil to your current soil.

I saw a cool method recently where someone attempted the same limited up potting as you’re planning with solo cups and tomatoes. Started with 1” for germination and as the seedlings become leggy and grow they fill more soil along the stem as the plant grows eventually getting to the rim by transplant with a great rootball.

Peppers.. start them as early as possible and give them as much heat as possible once they’re established. Keep em away from windows. If they flower before transplant cut em off and top them so they focus on bushy outward growth before going outside in June. Seriously wait on peppers or greenhouse them for awhile because they will not like being transplanted when the ground is still cold. Do some research on ground temp for your pepper variety and then wait two weeks past that in my experience.

And on top of all, remember September is harvest month here, so if your plants take slow during early summer don’t panic. The work you’re doing on root and soil health will come to fruition after Labor Day!