You can make your own hanging tomato plant quite simply, and you don't have to try to figure out how to grow the tomato upside down. Indeterminate tomatoes are vines that will grow up and over the edges of your plant pot, bearing tomatoes that will hang as bright red lobes out of the reach of any slugs or rodents found at ground level. The key to this whole project is keeping everything as lightweight as possible.
Prepare your hanging pot. One simple container that is sturdy enough to hold the weight of a large tomato plant but not too heavy to hang is a simple metal paint bucket. You can pick them up in home improvement centers for a couple of dollars. Hammer a large nail into the bottom of the bucket, then remove it to form several drainage holes. A 2 1/2 quart bucket should have about 6 holes in its base to allow for slow drainage without any soil loss.
Mix up your soil by using equal parts of potting soil, perlite, sphagnum peat moss and humus. You can use soilless potting soil for making the mixture even more lightweight, but then you will need to make sure your fertilize the plant weekly. Use a large enough container so you can mix it with water until the whole mixture has been moistened and there are no dry spots.
Turn the bucket right side up and fill it up with damp soil mixture. Poke an indentation into the soil as large as the root section of your tomato plant, but at least an inch deeper. Remove the tomato plant from the container and set it into the hole. Firm the soil up around the stem, leaving at least an inch of space from the top of the bucket for watering.
Use S-hooks to connect the chain to the handle on the bucket and to the hook from which you are hanging the plant. Make sure you are hanging the tomato in a place where it will get full sunlight for at least six hours a day.
Allow the plant to grow until it gets tall enough to start hanging over the sides of the bucket. It will continue to grow until the hanging branches are able to reach the ground. You can prune the end of the vines to keep them from growing further.
Water your hanging tomato plant everyday, if possible or at least often enough to keep the soil damp. Fertilize it with a commercial tomato plant fertilizer diluted with water once a week to make sure it gets enough nutrients.