buying heirloom tomatoes online
In-sanity! No ripe heirloom tomato worth having could stand even 24hrs in transit.
I was once in a tomato-growing e-mail loop that included a woman in NYC who grew her tomatoes on a ledge outside her window. I think she was called the 23rd Floor Gardener and she was celebrated in her building. There are also community gardens in NYC you could look for. And I'm sure there are growers' markets.
The only way you're going to get a tomato (heirloom or otherwise) that's worth eating is to grow them or buy ripe ones you carry home. Heirloom tomatoes are wonderful when they're ripe but they're also very fragile. If they're not fragile they're underripe and you won't like 'em. Frustrating but true.