Hi, buy the tomatoes you want to grow in the supermarket. Cut it, and take out the seeds, take away most of the gel around the seeds. Fold the seeds in paper towels, and let dry completely in the sun, one day is enough.
I cut the paper with seeds in strings (but you can carefully the seeds of the towel) and put all in the soil. When they sprout, I just keep the plants that looks the best.
I have done this many times with success with cherry tomatoes.
Careful with the green/red tomatoes, the birds love them too :-)
Have you tried using the using the 'hot' water tap (which is now turned off) instead of the cold? In our old apartment, the turned off hot tap was colder then the cold tap.
Ha ha, hope this makes sense :-)
