Frank wrote:

Thanks a lot for all your encouragement. Looks like I do have to pot
on to a muuuuch bigger pot. The 10 seeds are currently in the 6"
diameter pot. I put it by the southeast facing kitchen window and
anxiously waiting for its sprouts. oh, sounds like I have to keep only
the strongest one in the pot eventually. Do you just discard the other
ones or pot them somewhere else? Just a little hesitate to "kill". :-P

Yeah, this is my first year of gardening. And poor me, I don't have
any ground space, only have a balcony facing northwest. After I pot
the tomato to a bigger pot, I have to put it to the balcony. I'd be
very happy if I can get 2 tomatoes. :-) Finger crossed!

Normally you sow all your tomato seeds into a pot or box or whatever and
keep them warm (25°C). As soon as they get their fist 'real pair of leaves
you take the healthies ones and plant them into new pots, about 10-15cm
diameter. Plant them deeper than they were before. Give them much light.
After two or three days you could keep them cooler (about 15-16°C) with
much much light, they would flower earlier. If you can only keep them at
home between 20-25°C, no problem, they will just flower one or two weeks
later.
Here where I live, we can plant our tomatoes outdoors mid-may, when there
will be no late frost anymore. We plant them deeper again, they will get
more roots then.
You can plant them in a 10 liter pot or bucket. Did I mention that tomatoes
need lots of light...?
Don't give them a fertilizer with too much nitrogen, they will grow too
vigorously, but won't set more fruits. Use a fertilzer with more potassium
than nitrogen.
Professionels grow them without soil at all, just fertilizer solution. But
they have to take great care about the solution, hobbyists can't afford
this kind of analytics.

There are several hundred kind of tomatoes: 'normal' red ones, yellow ones,
almost black ones, tomatoes with stripes, pearshaped tomatoes, eggshaped
tomatoes, one pounders, two pounders, cherry-sized tomatoes...

If you have one of the cherry-sized cultivars, 200 tomatoes might be
possible, if there's enough sun for the plant. Tomatoes don't like too much
moisture, but don't let them dry up completely too often.

Use Google, there should be plenty of advice concerning tomatoes.

Bye,
Robert