Never grew them before. The plan is to get seeds from organic tomatoes from Meijer Store, then put them into double plastic cups with soil. Add compost in 2 weeks. Give them some light and water. In 4 weeks put them outdoors in pots with soil/compost a lot of sun. Fertilize/water them.
Is that a sound plan, please?

Plant the young plants out when the weather warms in your area. You'll need minimum 5-gallon pots or buckets and a stable support system installed at time of planting. Most cherry tomatoes are indeterminate and grow into long sprawling vines.

Organic isn't the issue, your Meijers tomatoes may not be carrying seed that will reproduce the same fruit as the one you gathered seed from. F1 seeds mean they come true from the parent ( if I remember right). You have a 50/50 chance of what you might have. Now if Meijers carries Heirloom tomatoes, those seeds stand a greater chance of being what you need to be growing. Organic in a tomato 🍅- well, they haven't been gene manipulated to be resistant to Roundup, so that isn't an issue. Organic is a growing method that I can't see affecting seeds anyway.
A brick of coco coir is maybe 5bucks and found in many stores and is 100% better than sand to start them in ( a brick dissolves into 2 gal of coir) mine in sand this year are struggling- the sand closes up and tightens around the seeds too much.


2nd washing of coir

See?

Ah, missed the part about getting seeds from store-bought tomatoes...thought OP was just buying the seeds at Meijers. Agree, heirlooms will work. Where did sand enter the conversation?

Zoe. @Maple11 raising description in original thread
My sand tends to not allow moisture to penetrate to roots, nor does it wick in those tall cups, I considered adding a paper towel wick to get moisture up but didn't

Kat, I'm totally confused. What original thread?

I'm unfamiliar with starting seeds in sand.

I am digging in the garden today with a 2 yr old great grandson, we have relocated at least 9 - 5 gal tubs of dirt today, forgive the exhaustion, but I meant the thread starter and changed the directive. Zoe you are in NM when the sand dries out and a cloud bursting gully washer comes thru, the water doesn't penetrate the sand, because the particles repulse moisture. Works on small pots and under Cumulo Nimbus towering cloud bursts exactly the same.

I still don't understand where sand came into the discussion either, the OP indicated "double plastic cups with soil."

@Maple11 , if you literally meant "soil," as in garden soil or whatever, I would suggest using a regular potting mix instead. Also, buying a packet of the type of seeds you want to grow would be more reliable than using any type of store-bought tomatoes.

After 4 weeks your seedlings will likely still be quite small, as well as the beginning of April seems like it might be early for planting in your area; wait until you aren't expecting any more freezing temps before putting the plants outside. Be sure to give your plants plenty of light while they're indoors so they don't become "leggy" and weak, and once you move them outside you will need to gradually acclimate them to the sun and wind.

Ugh, I read soil and thought sand, my life is comprised of sand right now.

OK, I will find the seeds at the store. I will concentrate on determinate tomatoes instead: Early Girl and Good Boy, right? I will mix the Top soil with the 40% compost and some perlite to retain the moisture. Last frost in my area is May 8, so I will start seeding around April 8. BTW, I never intended to use sand.

Both determinate and indeterminate tomato's can be non F1 seeds, if you are planting in 5 gal buckets then yes, determinate. I would send you seeds for a good cherry tomato but we just had a swap and my spares are gone, chuckl. THIS is my soil-

Maple11 said: OK, I will find the seeds at the store. I will concentrate on determinate tomatoes instead: Early Girl and Good Boy, right? I will mix the Top soil with the 40% compost and some perlite to retain the moisture. Last frost in my area is May 8, so I will start seeding around April 8. BTW, I never intended to use sand.

Did you mean "Early Girl" and "Better Boy" ? Neither of those varieties is the best for container growing (they are both "indeterminate" types), and definitely not "cherry tomatoes." I've grown "Red Robin" and "Patio" in the past and been quite happy with them, but there are LOTS of different varieties; mainly, look for the word "determinate" in the description and also the typical height of the plant, if given on the packet (some determinate tomatoes get tall enough that they need good support, others stay quite compact). Happy gardening!

I'll ask the same question Weedwhacker asked: by "top soil" do you mean soil from your garden? With added compost in a pot, I see drainage and water retention problems in your future. Use commercial potting mix, add perlite to that if you want, use compost only as a top mulch, not mixed in. Feed regularly throughout the entire growing season.