I agree that the seedlings were overwatered.

Why not try again, but buy a packet of potting mix (not soil). Punch some holes in the bottom of the OJ container (or you could use individual yoghurt containers).

You could also prop the plants up so that they are about a foot away from the light, or find a sunny window.

Linda

Second :

--- wrong soil ( Take the out and put in Soil less) potting mix.

-- Not enough light ( Your lights are too far away ...)

--- Wrong light ( Use CFL and keep within 2-3" from seedlings , min. 12 , max 18 hours/24 hr. )

--- Probably over watered.

I suggest starting them in seed trays. Use a well draining mix, I create a mix of mostly compost. But depending on the quality and type of the compost you use it may smell while in door, so you can find a good potting mix instead. I always make sure it have good drainage, but seed trays can get dry fast too depending on your grow mix. I water the seedlings with diluted molasses which give them quick
minerals while small, this is much more cost effective than buying
fertilizers. I keep the lights closer to the soil, but depending on the intensity you don't want the mix to heat up too much. I think tomato grows well when the soil is at least near mid-70*F.

Don't grow in containers that have standing water and can't drain. Be careful growing in peat-based mix, they can be very water retentive and rot the roots. Also peat by themselves do not have nutrients, so you would have to add additional through liquid fertilizers, which is why I prefer compost + molasses.

After 2-3 weeks (after germination), I transplant the seedlings from the seed trays into those plastic red cups. I have 2-3 holes under the cup for it to drain. After about 4 weeks I'm ready to transplant the tomatoes (some people wait to 6, it depends on the growth rate and climate situation).

Or you can grow directly from the plastic cups and skip the seed trays, they're pretty affordable. Don't try to save unhealthy seedlings since they will not grow well and won't be productive. It's better to start over.

There are stuff in tap water, like Chlorine to help disinfection, but they are not in strong enough concentration to harm your plants or prevent germination. I do prefer to use filtered or rain water when I can.

If you're in a dorm, tomatoes, at least normal ones may not be the plants for you. Tomatoes get huge and need tons of light. You don't have the space or windows. Why not spring for a dwarf tomato or something better suited to your situation, like spinach or lettuce? They're good beginner plants, don't take up tons of space and you'll get to eat them by the end of your term.

Dear all, thank you very much for replying. Now I know where the issue is. I have lowered the light and stopped watering for now, and will only water when the soil become dry enough. Hopefully this will solve the lighting and watering problem. As for the soil, I have asked stores around and there is no store nearby that sells potting mix. Is it too late to change into potting mix? If not too late, can someone recommend some potting mix which I can buy online, preferably from Amazon where I always buy things?

Some people asked why I choose to plant tomato in my dorm. Actually it was because of this: one day I was eating tomato in a bowl, and afterwards I left the bowl filled with water, intending to wash it later. But due to laziness I did not wash the bowl for a few days and there were 3 tomato seeds inside the bowl, which started to germinate. I could not bear to throw them away since they are now living things. I also found it amazing because I microwaved the original tomato that contained these seeds for 2 minutes in my microwave oven before I ate it. Thus I decided to grow them. I know the difficulties of growing them in my dorm but I decide to grow them anyways and move one step at a time and see what happens.

Likely if you eat tomatoes from the store they are production tomatoes. 1. They won't have the taste like a good gardener hybrid or heirloom tomato (in other word they tastes like cardboard). 2. They are hybrid, when you replant a seed from a hybrid plant, it won't be exactly like the original plant, it will have different characteristic and may not taste as good or have desired traits. I would rather order some seeds online and grow some dwarf tomato instead.

If you intend to grow indoor you will need some good lighting and space. Something like this is minimum I would recommend for full size tomato indoor: https://www.1000bulbs.com/product/8256/FC105-S50OD.htm. So as you can see, tomato need lots of light which isn't not going to work in a single room dorm. Not only that, they need lots of soil, at least a 5 gallon container. So it's better off growing something like lettuce or basil indoor, or look for a dwarf or microdwarf tomato variety. Some variety to consider are: Red Robin, Tiny Tim, Silvery Fire Tree.

For indoor potting soil, make sure you ask question and find the right potting soil that does not smell and perhaps pasteurized for indoor use, otherwise it will be an unpleasant experience. I don't buy potting soil, but I know "FoxFarm's Potting Soil" have good reputation so you may want to check them out, but I don't know how it'll smell.

In my bedrooom I have an "AeroGarden Extra LED" that let me grow vegetable hydroponically, and it's LED light is bright enough to provide light for some extra plants in smaller container next to it. It is full spectrum and would be adequate for small dwarf tomatoes. It have a timer and shuts off after 12-16 hours. It is also very easy to make your own affordable indoor hydroponic setup. However, considering you live in a dorm, I don't know if you may have issues with campus authority who will be concerned with cannabis growing which is quite popular with hydroponic growing (not that I'm trying to give an idea).

The pots are way too big too. They will be chronically overwatered in such big pots. I also suggest you research "potting up". I chronicled a good portion of my seed starting this year... http://forums.gardenweb.com/discussions/2993293/tomatoes-and-eggplants-growing-fast

They were started in seed starting trays, in Nature's Promise seed starting mix (organic Miracle Gro), which was great. That light is not going to work either... I strongly suggest at least a cheap grow light.

Also it is way too early to start seeds in Philly! Around April 1st was my plan. In Philly mid March maybe.