Hi Kim, here are a couple of links to help you manage your new tomatoes. https://catalog.extension.oregonstate.edu/em9128/html

https://extension.psu.edu/tomatoes-from-seedlings-to-fruit

Generally, new seedlings do not need to be fertilized before they have 3-4 true leaves on them. Often times gardeners will wait until they either transplant tomatoes into a 4" nursery container or into the ground before fertilizing them. Using a low nitrogen fertilizer is best for tomatoes. Nitrogen is the first number on the fertilizer package. For example, 6-4-4 means 6% N. It is up to you what fertilizer you choose. 

For future reference when sowing seeds indoors I thought you might be interested in this publication. https://extension.oregonstate.edu/gardening/techniques/when-start-seeds-indoors-oregon

Have fun with your tomatoes

Hi Kim, these plants are pretty small for the size of the container you have them in. Normally when you transplant seedlings you put them into 4" container (or small pot) them as they grow to 4-6" they are ready for the large pot. 

I cannot say for sure what the issue is other than it is likely they are being overwatered in the large container. I am not sure what you used as potting medium in the large pots but it looks very woody and not really like a potting medium for small plants. 

You can use a pelleted, slow-release balanced fertilizer (10-10-10) and mix into a light potting medium or use a liquid fertilizer diluted by half until the plant gets at least 6-8" tall. Follow the product instructions except dilute it when the plants are still small. 

It looks like you may have the plants near a window. If the window gets sun coming through it the brown on the leaves may be sunburn from too much direct sun. This is hard to say for sure from photos. 

I hope you can nurse the plants back to health but it may be wise to get a couple of plants from a store or local sale to ensure some success for this year. You can use the knowledge gained this year to try growing from seed again next year. 

Toni

Hi Kim, the yellowing looks to be on the lowest/oldest leaves. This is usually an indication that Nitrogen is needed. It can also be that the oldest leaves are starting to die out but these plants are too young for that to be the problem. Nitrogen is a mobile nutrient and if the new growth needs it the oldest growth gives it up (so to speak). Time to fertilize. When plants are in containers the Nitrogen can also be leached out so using a liquid fertilizer when you water (according to instructions on product) helps keep N available.