Safe fertilizer for upside down tomato

 About a month ago I planted an upside down tomato using topsoil and organic compost.  I want to fertilize it but I'm concerned about using chemical fertilizer for vegetables, especially in such a concentrated environment.  What should I be looking for at the store for fertilizing my tomato plant.  I have basil and and a patio tomato, too, I'm concerned about.  I grow nice flowers, but I've never grown vegetables.

Go to a good nursery and ask for a liquid organic fertilizer. There are many brands, as long as it says organic, you'll be OK.

If you can't find that go for Gardentone, it's organic, granular and easy to find.

Good luck, let us know how it turns out.